3,128,297 United States Patent Office Patented Apr. 7, 1964 1. 2 The various operable organo-silicon compounds, operable 3,128,297 catalysts and reaction conditions will now be defined in PROCESS FOR SELICON-HALOGEN BOND more detail. The term "halogen' as used herein includes RED STRIBUTION the elements fluorine, chlorine, bromine and iodine. Bernard Kanner, Tonawanda, and Donald L. Bailey, Sny Monomeric silanes which can be employed as reactants der, N.Y., assignors to Union Carbide Corporation, a in the process of this invention may be represented by corporation of New York No Drawing. Filed Mar. 31, 1961, Ser. No. 99,667 the formula: 20 Claims. (C. 260-448.2) (B) R (Y-R-) six This invention relates to a process for the redistribution 10 wherein R is a divalent hydrocarbon group, the Y group of silicon-halogen chemical bonds. More particularly, is hydrogen, fluoro, chloro, bromo, iodo, cyano, the invention is directed to a process for the redistribution O of silicon-fluorine and other silicon-halogen bonds, pref -COO G, -NG, G -O G, erably silicon-chlorine bonds, in organo-silicon com -V-va, pounds. This application is a continuation-in-part of our 5 or nitro, the R' group is hydrogen, the vinyl group or an copending application Serial No. 15,841, filed March 18, Y-R- group, X is a halogen, G is a monovalent hy 1960, now abandoned. drocarbon group, e is an integer having a value from 0 We have discovered that an efficient and rapid redis to 3, f is an integer having a value from 0 to 1 and the tribution of silicon-fluorine and other silicon-halogen sum of e and f is never greater than 3. bonds takes place at moderate temperatures when an or 20 The divalent hydrocarbon group R is preferably one gano-silicon compound or mixture of organo-silicon.com containing between one and 17 carbon atoms and may be pounds wherein there is at least one silicon-fluorine bond an alkylene group such as methylene, ethylene, butylene and at least one other different silicon-halogen bond is (1,4), hexylene (1,2), 2-ethylhexylene (1,6 and the like, contacted with a basic catalyst. For example, if trimeth a cycloalkylene group such as cyclopentylene (1,3), cyclo ylfluorosilane and methyltrichlorosilane are contacted 25 hexylene (1,4), 3-octylcyclohexylene (1,4) and the like and with triethylamine at about room temperature a redis an arylene or alkarylene group such as phenylene (1,4), tribution reaction takes place according to the equation: naphthalene (1,4), 2-ethylphenylene (1,4) (A) catalyst (CH3)2SiF -- CHSiCl3 e 30 (CH3)3SiCl -- CH3SiF Cl2 + CH3SiFC 1 - CH3SiF ÖH, The methods heretofore proposed for the redistribution of silicon-halogen bonds resulted in extremely slow CH CH, CH, GH, reactions even at relatively high temperatures. For ex / YoH- - /N ample, in J. Am. Chem. Soc., vol. 70, 3068, (1948), it 35 was reported that trimethylchlorosilane did not react with - ÖH, FSi(Me) CHSiMe2F to any detectable extent. When cí. , aluminum chloride, a Lewis acid, was added to the mix and the like. ture a very slow redistribution reaction took place at 40 The monovalent hydrocarbon group G is preferably one elevated temperatures. Another article in the J. Am. containing from one to 10 carbon atoms and may be Chem. Soc., vol. 72, 2091, (1950), reports that the re alkyl, cycloalkyl, aryl or alkaryl. Examples of the group distribution reaction involving SiC and SiF4 proceeded G are methyl, ethyl, isobutyl, hexyl, 2-ethylhexyl, cyclo very slowly even at 740 C. It was estimated that a tem pentyl, 2-ethylcyclohexyl, phenyl, tolyl, mesityl, cumyl, perature of 900° C. to 1000° C. would be required to and naphthyl. attain an equilibrium mixture of redistribution products 45 Typical monomers which can be employed in this within a reasonably short reaction time. It is, therefore, an object of this invention to provide process are a process for the redistribution of silicon-fluorine and silicon tetrachloride, other different silicon-halogen bonds in organo-silicon methyltrichlorosilane, compounds which is not subject to the disadvantages of 50 phenyltrichlorosilane, the methods heretofore known. naphthyltrichlorosilane, An additional object of this invention is to provide an ethyltrichlorosilane, efficient process for the production of organo-silicon com tricholorosilane, pounds containing silicon-fluorine and/or other silicon methyldichlorosilane, halogen bonds. 55 phenyldichlorosilane, A further object of this invention is to provide a process dimethyldichlorosilane, for producing organo-functional silicon halide compounds diphenyldichlorosilane, containing functional groups in the organic portion of phenylmethyldichlorosilane, the molecule. trimethylchlorosilane, A still further object of the invention is to provide a 60 phenyldimethylchlorosilane, process for the purification of chlorosilanes, bromosilanes dichlorosilane, and iodosilanes. bis-trichlorosilylbenzene, Other objects will be apparent from the following de tolydiphenylchlorosilane, tailed description and the appended claims. beta-cyanoethyltrichlorosilane, Broadly stated the process of this invention comprises 65 m-fluorophenylvinyldichlorosilane, contacting an organo-silicon compound or mixture of p-iodobenzyltrifluorosilane, organo-silicon compounds (provided, of course, that in nitrophenyltrichlorosilane, these organo-silicon compounds there is at least one sili bis-nitrophenyldichlorosilane, con-fluorine bond and at least one other different silicon cyanophenylmethyldichlorosilane, halogen bond) with a basic catalyst and heating the re 70 gamma-chloroisobutyltrichlorosilane, sulting mixture to a temperature sufficiently elevated to gamma-cyanopropyltrichlorosilane, cause the silicon-halogen bond redistribution to take place. beta-carbethoxyethyldichlorosilane, 3,128,297 3. 4. delta-nitrobutylmethyldichlorosilane, Also included in the operable monomeric silanes are 4-trichlorosilyl-N,N-dimethylbenzamide, mixed chloro-, bromo- iodo- and fluorosilanes such as di delta-bromobutyltrichlorosilane, methylfluorochlorosilane, 4-acetylphenylmethylchloro methoxyphenyltrichlorosilane, fluorosilane, phenyldichlorofluorosilane, beta-cyanoethyl phenyltrifluorosilane, 5 difluorochlorosilane, diethylchlorobromosilane, phenyl diphenylidifluorosilane, fluorobromoiodosilane and nitrophenylmethylfluoro silicon tetrafluoride, chlorosilane and the like. methylvinylidifluorosilane, Linear and cyclic polysiloxane polymers can also be beta-cyanoethyltrifluorosilane, used in the process of this invention. Operable linear gamma-chloroisobutyltrifluorosilane, 10 polysiloxanes can be represented by the formula: gamma-(N-methyl-N-phenylamino)propyltrifluorosilane, (C) R-Y R-Y beta-phenoxyethylmethylidifluorosilane,nitronaphthylmethylidifluorosilane, s -4-x. beta-phenylethyltrifluorosilane, R-Y y R-Y silicon tetrabromide, wherein R, Y and X have the meanings defined herein methyltribromosilane, above and y is an integer having a value from 1 to 10,000. phenyltribromosilane, Examples of operable linear siloxanes are 1,5-dichloro naphthyltribromosilane, hexamethyltrisiloxane, 1,3-dichlorotetramethyldisiloxane, ethyltribromosilane, 1,3-difluorotetraphenyltrisiloxane, 1,7-dichlorooctamethyl tribromosilane, ' tetrasiloxane, 1,5-dibromohexamethyltrisiloxane, 1-chloro, methyldibromosilane, 3-iodo-tetramethyldisiloxane, and the like. phenyldibromosilane, The cyclic polysiloxane polymers which can be em dimethyldibromosilane, ployed in the process of this invention may be represented diphenyldibromosilane, by the formula: phenylmethyldibromosilane, 25 s trimethylbromosilane, (D) 1–Y phenyldimethylbromosilane, -Si-O -Si-O dibromosilane, k-y r k-y s tolydiphenylbromosilane, beta-cyanoethyltribromosilane, 30 wherein R, Y,X have the meanings defined hereinabove, beta-carbethoxyethylmethyldibromosilane, r is an integer having a value from 1 to 3 and s is an nitrophenyltribromosilane, integer having a value from 2 to 10 with a preferred bis-nitrophenyldibromosilane, range of from 2 to 4. Examples of operable cyclic poly cyanophenylmethyldibromosilane, siloxanes include chloroheptamethylcyclotetrasiloxane, gamma-chloroisobutyltribromosilane, 35 chloropentamethylcyclotrisiloxane, iodopentamethylcyclo beta-carbethoxypropyltribromosilane, trisiloxane, dibromohexamethylcyclotetrasiloxane, fluoro gamma-cyanopropyltrichlorosilane, heptaethylcyclotetrasiloxane, and the like. delta-nitrobutylmethyldibromosilane, The redistribution process of this invention applies to delta-N,N-dimethylaminobutyldimethylbromosilane, mixtures of silanes, linear polysiloxanes and cyclic poly delta-bromobutyltribromosilane, 40 siloxanes, and includes the redistribution of silicon N,N-diethylaminophenylmethyldibromosilane, fluorine bonds with mixtures of silicon-chlorine, silicon methoxyphenyltribromosilane, bromine and silicon-iodine bonds. beta-methoxyethylmethyldibromosilane, The operable basic catalysts in the process of the pres delta-ethylmercaptobutyltribromosilane, ent invention are tertiary amines, tri(monovalent hydro silicon tetraiodide, 45 carbon group) phosphines and silylamines. The term methyltriiodosilane, "tertiary amine” as used herein means a class of com phenyltriiodosilane, pounds wherein all three normal valences of the nitrogen naphthyltriiodosilane, atoms in Such compounds are bonded to carbon atoms ethyltriiodosilane, of hydrocarbon moieties. Thus, the term “tertiary triiodosilane, 50 amines' includes tri(monovalent hydrocarbon group) methyldiiodosilane, amines and pyridines, for example, triethylamine triso phenyldiiodosilane, propylamine, t-butyldimethylamine, cumyldimethylamine, dimethyldiiodosilane, and 2,2-bipyridyl. Examples of operable tertiary amines diphenyldiiodosilane, catalysts are tri-n-butylamine, trimethylamine, methyl phenylmethyldiiodosilane, 55 ethylpropylamine, tri-n-heptylamine, triethylamine, ethyl trimethyliodosilane, hexyloctylamine, N,N-dimethylaniline, N-methyl-N-butyl phenyldimethyliodosilane, aniline, alpha-methyldimethylbenzylamine, tribenzyla diiodosilane, mine, triphenylamine, N-methyl-alpha naphthyl-phenyl tolyldiphenyliodosilane, amine, pyridine, quinoline, alpha-picoline, isoquinoline, beta-cyanoethyltriiodosilane, 60 2,2-bipyridyl, 2,2-biquinoly, 2,6-lutidine, 2,4,6-trimethyl beta-carbethoxyethylmethyldiiodosilane, pyridine, 2-methylquinoline, N-methylmorpholine, and nitrophenyltriiodosilane, the like. bis-nitrophenyldiiodosilane, Examples of tri(monovalent hydrocarbon group) phos cyanophenylmethyldiiodosilane, phine compounds which are operable catalysts in the gamma-chloroisobutyltriiodosilane, 65 process of the present invention are tributylphosphine, beta-carbethoxypropyltriiodosilane, triphenylphosphine, phenyldiethylphosphine, methyldi gamma-cyanopropyltriiodosilane, butylphosphine, phenyltolylbutylphosphine, tribenzyl delta-nitrobutylmethyldiiodosilane, phosphine, ethylbutylhexylphosphine and the like. delta-N,N-dimethylaminobutyldimethyliodosilane, 70 The silylamines which are operable catalysts in the delta-bronobutyltriiodosilane, present invention may be represented by the formula: N,N-diethylaminophenylmethyldiiodosilane (E) Gm-Si(NG) 4 methoxyphenyltriiodosilane, Wherein G has the meaning defined above with reference beta-methoxyethylmethyldiiodosilane, to formula B, and n is an integer having the value of delta-ethylmercaptobutyltriiodosilane, and the like. 75 Zero to three. Examples of the silylamines that may be 8,128,297 5 6 employed in this process are trimethyl-N,N-dimethyl q)=phenyl and DMF=N,N-dimethylformamide. Also, a aminosilane, dimethyldi-N,N-diethylaminosilane, phenyl figure in degrees written under the formula for a chem tri-N,N-dibutylaminosilane and the like. ical compound indicates the normal (atmospheric pres Ammonia, primary amines and secondary amines may sure) boiling point of the compound in degrees centigrade. also be used, indirectly, as catalysts for the process of In order to emphasize the principal reactions taking the present invention. When these compounds are added place, the chemical equations hereinbelow are not bal to a mixture of halosilanes they react at the silicon-fluorine anced and show only the primary reaction products. or other silicon-halogen bonds to give silylamines and By appropriate methods, the redistribution reaction of other products. The silylamines thus formed are included the present invention can be driven to completion thus in Formula Ehereinabove and catalyze the redistribution 0. providing a route for the preparation of various com reaction of this invention. pounds containing silicon-fluorine and other silicon The redistribution reaction of this invention can be halogen bonds. For example, the process shown in carried out without the use of a solvent. However, inert Equation A above can be driven to completion by using Solvents can be used if desired, and are frequently bene a stoichiometric excess of one of the reactants or by ficial when one or more of the reactants is a polysiloxane. 5 removing one or more of the products from the reaction The term "inert” indicates that the solvent does not react mixture. With silicon-halogen bonds or with functional groups on In particular, many fluorosilanes are desirable as re the organic portion of the organo-silicon compounds. action intermediates and for other purposes. Methods Examples of operable inert solvents are benzene, hydro heretofore known for preparing fluorosilanes had certain carbon-substituted benzenes, such as toluene, xylene, 20 serious disadvantages. For example, one method was to cumene and tetrahydronaphthalene, hydrocarbons such react an appropriate halosilane with an alkali metal as heptane, octane and petroleum ether and ethers such fluorosilicate such as Na2SiF6 as diethyl ether, dibutyl ether, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether and diethylene glycol (F) pSiCl2--Na2SiF6) (bSiF--SiF--2NaCl dimethyl ether. 25 While this is a convenient laboratory procedure it is The temperature at which the base catalyzed redis commercially undesirable to employ large amounts of tribution reaction of the present invention takes place is solids as required by the reaction. In addition, many not critical. The reaction generally takes place rapidly halosilanes are not normally reactive towards Nafs at moderate temperatures thus providing an exceptionally because of relatively low boiling points. efficient process. The preferred operating temperature 30 Another method heretofore used involved the reaction range is from about -20° C. to about 200° C. but higher of a halo-silicon compound with certain metal fluorides or lower temperatures may be used if desired. such as SbF3. Pressure is also not a critical factor in the process of (G) CHSiCl3--SbF-> SbCl. --CHSiF3 this invention. The most convenient pressure for carry ing out the reaction is atmospheric pressure. However, 35 This procedure is also unattractive commercially because the reaction can be carried out under pressure, if desired, of the cost and inconvenience of handling metal fluorides and it is also frequently advantageous to use sub and because of the low reactivity of volatile halosilanes. atmospheric pressures when it is desired to carry the By driving the rapid redistribution reaction of the redistribution reaction to completion. This feature of the present invention to completion an efficient process for process will be discussed in more detail below. 40 the production of a wide variety of fluoro-silicon or other The reaction times necessary to effect redistribution halo-silicon compounds is obtained. For example, the of the silicon-fluorine and other silicon-halogen bonds redistribution of phenyltrifluorosilane with silicon tetra according to the process of this invention are likewise chloride readily goes to completion because one of the not critical. The exact length of time required to form products, silicon tetrafluoride is extremely volatile and an equilibrium mixture of redistributed products varies, leaves the reaction mixture as a gas as rapidly as it is of course, with the temperature, the nature of the organo formed. silicon compounds and the particular catalyst present. It (H) GN can be stated in general, however, that redistribution to bSiF3 - SiCl, -}. (bSiCl3 -- SiF4 an equilibrium mixture takes place within relatively very GN represents a tri(monovalent hydrocarbon group) short periods of time. 50 amine, G having been defined with reference to Formula B It is pointed out that the redistribution process of the above. The yield of phenyltrichlorosilane is also improved present invention does not require the presence of two by using an excess of silicon tetrachloride. different halosilanes, or halosiloxanes. A single com By taking advantage of differences in boiling point, pound is sufficient as long as it contains at least one one can readily convert a fluorosilicon compound to a silicon-fluorine bond and at least one other different 55 chloro-silicon compound or other halo-silicon compound silicon-halogen bond. For example, phenylfluorodichloro or vice versa. Thus to convert methyldichlorosilane to silane in the presence of a tertiary amine undergoes a methylidifluorosilane the former is reacted with a fluoro redistribution reaction to give a mixture of products silane having a higher boiling point in the presence of which include phenyltrichlorosilane and phenyldifiuoro a catalyst such as a tertiary amine. As methyldifluoro chlorosilane. In the case of dimethylfluorochlorosilane 60 silane is the most volatile component of the system, it is the silicon-halogen bonds redistribute and the reaction readily removed by distillation. (I) G3N mixture contains dimethyldichlorosilane and dimethyl bSiF3 - MeSiHCl2 - MeSiHF -- SiCl3 difluorosilane. 101 429 -33° 2009 As used herein the terms "chlorosilane,' "bromo Similarly, if it is desired to convert gamma-cyano silane,” “iodosilane' and "fluorosilane” refer to com 65 propylmethyldifluorosilane to the corresponding chloro pounds containing silicon-chlorine bonds, silicon-bromine silane it is reacted with a lower boiling chlorosilane such bonds, silicon-iodine bonds, silicon-fluorine bonds or as silicon tetrachloride. Gamma-cyanopropylmethyl mixtures of such bonds regardless of the functional groups dichlorosilane is produced in good yield as the reaction present in the organic portion of the molecule. Thus, is driven to completion by the evolution of silicon gamma-chloropropyltrifluorosilane is a fluorosilane and 70 gamma-iodopropylfluorodichlorosilane is a fluorosilane tetrafluoride. (J) and a chlorosilane. GN In the description of the invention hereinbelow, the gamma-NC C3H5SiMe2 -- SiCls --> following abbreviations are employed: Me=methyl, 1950 57o SiF 4 -- gamma-NCCHSiMeCl Et=ethyl, iBu-iso-butyl, Ac-acetyl, Vi-vinyl, 75 -95 243° 3,128,297 7 8 In general the starting materials which can be used flask: 250 grams (1.54 moles) of phenyltrifluorosilane, when the redistribution reaction is to be driven to com 175 grams (1.52 moles) of methyldichlorosilane and 2 pletion are the silanes and polysiloxanes outlined in For grams of tri-n-hepytlamine. The reaction mixture was mulas B, C and D hereinabove. It is, of course, necessary heated at its boiling point. The volatile products were that an excess of at least one of these reactants may be fractionated through a packed gas distillation column. used or that at least one of the products may be removed About 60 grams of methyldifluorosilane and about 40 from the reaction mixture. The detailed procedures by grams of methylchlorofluorosilane were obtained. which the redistribution reaction is driven to completion depend, therefore, on the nature of the individual reaction EXAMPLE 7 mixture and the appropriate procedures will be apparent O The following were combined in a one liter distillation to those skilled in the art. Several desirable procedures flask: 131 grams (0.422 mole) of bis(nitrophenyl) difluo are described in the illustrative examples appearing here rosilane, 136 grams (0.8 mole) of silicon tetrachloride, in below. 100 milliliters of benzene and 0.5 milliliter of tri-n-heptyl Example 1 through 11 hereinbelow are illustrative of amine. Upon mixing an imediate evolution of gas took the general nature of the redistribution process of the 5 place. After the evolution of gas had subsided the reac present invention and of the use of this process in isolating tion mixture was heated at its boiling point for 2 hours various chloro-, bromo-, iodo- and fluorosilanes. and then cooled to room temperature. On cooling over night crystals precipitated out of the reaction mixture. EXAMPLE 1. The crystals were separated from the reaction mixture and The following were combined in a 200 milliliter distilla 20 purified by washing with diethyl ether. The purified crys tion flask: 46 grams (0.41 mole) of trimethylchlorosilane, tals weighed 109 grams and were identified as bis(nitro 120 grams (0.74 mole) of phenylmethyldifluorosilane and phenyl) dichlorosilane. This example illustrates the use 1 gram of tri-n-hexylamine. The mixture was heated at of an inert solvent and also illustrates the recovery of a its boiling point and trimethylfluorosilane as formed was desired product by crystallization techniques. continuously removed by distillation through a packed col umn. A total of 34.5 grams of trimethylfluorosilane hav EXAMPLE 8 ing a boiling point of 20 C. was recovered. This repre The following were placed in a 2 liter distillation flask: sented an 88 percent conversion of the trimethylchloro 479 grams (3.2 moles) of gamma-cyanopropylmethyldi silane to trimethylfluorosilane. fluorosilane, 1091.4 grams (6.4 moles) of silicon tetra 30 chloride, 3 grams of tri-n-heptylamine and 1 gram of tri EXAMPLE 2 laurylamine. An exothermic reaction took place at about The following were combined in a 500 milliliter distilla room temperature. To insure complete reaction the mix tion flask: 101.5 grams (0.50 mole) nitrophenylmethyldi ture was maintained at 60° C. for 15 hours with stirring. fluorosilane, 127.5 grams (0.75 mole) of silicon tetrachlo Unreacted silicon tetrachloride was removed by fractional ride and 1 gram of tri-n-heptylamine. Upon the addition distillation at atmospheric pressure. The remaining crude of the amine to the reactants at room temperature an im product was further distilled at atmospheric pressure and mediate and vigorous evolution of silicon tetrafluoride gas 511.5 grams of gamma-cyanopropyimethyldichlorosilane took place. The reaction appeared to be substantially having a boiling point of 242 C. to 244 C. was recov complete in less than one hour. The reaction mixture was ered. This represents an 87.5 percent conversion of allowed to remain at room temperature overnight and was 40 gamma-cyanopropylmethylidifluorosilane to gamma-cyan then fractionally distilled through a packed column. A opropylmethyldichlorosilane. total of 109 grams of nitrophenylmethyldichlorosilane hav ing a boiling point of 103 C. to 109 C. at 2 mm. was EXAMPLE 9 collected. This represents a 90 percent conversion of ni The following were combined in a 200 milliliter distilla trophenylmethylidifluorosilane to nitrophenylmethyldichlo tion flask: 32 grams (0.20 mole) phenylmethyldifluoro rosilane. silane, 52 grams (0.20 mole) of silicon tetrabromide and EXAMPLE 3 0.3 milliliter of phenyldiethylphosphine. Upon the addi The following were placed in a 500 milliliter distilla tion of the phosphine to the reactants at room tempera tion flask: 81.5 grams (0.50 mole) of phenyltrifluoro ture an immediate evolution of silicon tetrafluoride gas silane, 125.5 grams (0.74 mole) of silicon tetrachloride 50 took place. The reaction mixture was heated to its boil and 0.5 gram of tri-n-hexylamine. Upon addition of the ing point and was then fractionally distilled through a 12 amine to the reactants at room temperature a vigorous inch Vigreux column. A total of 49 grams of phenyl evolution of silicon tetrafluoride gas took place and the methyldibromosilane having a boiling point of 232 C. to temperature of the reaction mixture dropped to below 237 C. at atmospheric pressure was collected. This rep room temperature. The reaction mixture was then rapid 55 resents an 87 percent conversion of phenylmethyldifluoro ly fractionated through a short Vigreux column to yield silane to phenylmethyldibromosilane. 25.5 grams of silicon tetrachloride, 7 grams of material having a boiling point range of 128 C. to 192 C. and EXAMPLE 10 95.4 grams of phenyltrichlorosilane having a boiling point Following the procedure of Example 9, phenylmethyl of 192° C. to 198°C. A pot residue of less than 4 grams 60 difluorosilane and silicon tetraiodide are mixed and phen remained. A 90 percent conversion of phenyltrifluoro yldiethylphosphine is added. The reaction mixture is silane to phenyltrichlorosilane was obtained. then heated to its boiling point and fractionally distilled. The principal product recovered is phenylmethyldiodo EXAMPLE 4 silane. Following the procedure of Example 3 phenyltrifluoro 65 EXAMPLE 11 silane was converted in high yield to phenyltrichlorosilane The following were combined in a 200 milliliter distilla using phenyldiethylphosphine as a catalyst. tion flask: 26.4 grams (0.177 mole) gamma-cyanopropyl EXAMPLE 5 methyldifluorosilane and 47.5 grams (0.177 mole) of sili Following the procedures of Example 3 phenyltrifluoro con tetrabromide. The solution was heated to its boiling 70 point (about 151 C.) but there was no gas evolution silane was converted in high yield to phenyltrichlorosil or other indication of any chemical reaction. The solu ane using trimethyl-N,N-diethylaminosilane as the cata tion was then allowed to cool to 40 C. and one milliliter lyst. of 4-picoline was added. Upon the addition of the amine EXAMPLE 6 to the reactants a rapid evolution of silicon tetrafluoride The following were placed in a one liter distillation 75 gas took place, and the temperature of the reaction mix 3,128,297 9 O ture rose to 52° C. The reaction mixture was heated at possible by this invention, provides a method for prepar 100° C. for one hour and was then fractionally distilled ing useful organo-functional chlorosilanes in high yield under reduced pressure through a 12 inch Vigreux column. by relatively uncomplicated process steps. This embodi A total of 41 grams of gamma-cyanopropylmethyldibro ment is described below with particular reference to mosilane having a boiling point of 100° C. to 103 C. at 5 chlorosilanes. 1 mm, was collected. This represents an 85 percent con Alkyl and arylchlorosilanes are basic intermediates both version of gamma-cyanopropylmethyldifluorosilane to for the preparation of silicone polymers such as oils, res gamma-cyanopropylmethyldibromosilane. ins and elastomers as well as for the synthesis of other The above examples show that a convenient amount silanes. These materials can generally be used to advan of catalyst for use in the redistribution process of this 0 tage in this manner because many chlorosilanes are com invention is between about 0.3 and about 0.6 weight per mercially available, they can be hydrolyzed fairly simply cent based on the total weight of organosilicon com to form siloxane polymers and they enter satisfactorily pounds present in the reaction mixture. In Example 1, 1 into many reactions. Chlorosilanes do have certain in gram of catalyst was used for 166 grams of organosilicon herent limitations, however, particularly when used as in compounds, or 0.6 weight percent. Smaller or greater 5 termediates for the preparation of other silane monomers. amounts of catalysts are operable, however, and between Most of these difficulties are related to the reactivity of about 0.001 and about 10 weight percent catalyst based silicon-chlorine bonds with a wide variety of reagents. on total weight of organosilicon compounds is preferable. Thus, while it is desirable that chlorosilanes react rapidly Amounts greater than 10 weight percent or less than 0.001 and completely with water to form siloxanes it is unde Weight percent can be used, but without any noticeable 20 sirable to have reaction take place at the silicon-chlorine advantage over the preferred amounts. bond when reaction at another portion of the molecule In many instances it is preferable to use a catalyst is being sought. For example, it might be desirable to which has a high boiling point relative to some compo esterify a cyanoalkylchlorosilane as shown below. (K) nents of the reaction mixture. For example, if a particu 25 HCl lar fluorosilane is to be recovered from a reaction mix NC (CH)3SiCl3 -- Et OFI - HO --> ture by fractional distillation, it is preferable to use cata O lyst which has a higher boiling point than the product to be recovered. The precise choice of catalyst of course, EtO 3-(CH.) 3SiCl3 - NH4C depends upon the components of the particular reaction Instead, however, water present will react preferentially mixture and the particular products which may be re 30 to hydrolyze the chlorosilane to give the corresponding covered. polysiloxane which then may react to give the desired Phosphines have been found to be particularly useful ester. catalysts in reactions where hydrogen chloride or other hydrogen halide may be produced, as where trace amounts of Water are present in the reaction mixture. Phosphines do not form hydrochloride salts with HCl while the for mation of solid amine hydrochlorides may make the sepa Thus, one obtains the carbethoxy derivative of a silicone ration of products in the reaction mixture more difficult. rather than of a chlorosilane. Similarly, a number of A preferred embodiment of the redistribution process other reactions of chlorosilanes with reagents proceed to of the present invention is the use of this process in the 40 give products other than those originally desired. The preparation of organo-functional, chloro-, bromo-, and equations that follow all illustrate reactions taking place iodo-silanes. For example, the efficient redistribution of preferentially at the Si-Cl bond rather than the desired silicon-chlorine and silicon-fluorine bonds, which is made reaction which is shown first, (L-1) GSNa -- Cl-(CH2)3SiCl3 - GS-(CH2)3SiCl3 - NaCl

Ny Cl cichs-s-g -- NaCl

(L-2) GNH -- Cl(CH2)3SiCls - GNH(CH2)2SiCl3 - GN:HC

N Y C1 Cl(CH) SINHG -- GN:HCI Cl (L-3) GO Na -- Cl(CH2)3SiCl3 - GO (CH2)2SiCl3 -- NaC

N Y Cl(CH) Si(OG) Cls -- NaCl O O I (L-4) GOH -- Cl-C-(CH2)SiCl3 -) GOC-(CH2)3SiCl3 -- HCl

N Y mixture of SiO G and -COO G OH (L-5) CH=CH-(CH2)3SiCls -- ECHO -- HOAc -- HaSO4 -) Hoch-CH-CH (CH) siCl,

NY complex mixture 3 1. 28,297 2

(L-6) GOOC (CH) aSiCl3 - NH3 - HNC-(CH)SiCl3

Yi GOOC (CEI)SiNH -- NHC1 O (IL-7) CH=CH-CH-CH-SiCl3 - CHCOOOH --> CHACE-CH-CH-SiCl3

N Y unsatisfactory (L-8) (EtO)2PH -- CE=CH-SiC -- peroxide -- (EtO)P-(CH2)SiCls N Y CH-cCH-Si-OP= -- others A (IL-9) (EtO)3P -- Cl-(CH2)3SiCls --> (EtO)2PO-(CH2)3. SiC ls

N Y Cl-(CH2)3Si-O (OEt); -- others GONa (LiO) GOH -- CH=CH-SiCls - GO-(CH)SiCl3

Y. CH=CH-Si(OG) CI -- HCl GSNa (IL-11) GSH -- C=C-SiCls - G-S-(CH2)2SiCls

N Y CH=CH-Si(SG) Cls -- HCl (IL-2) C: CH -- CH=CH-SiCl3 - peroxide - ClaC-(CH)2SiOl

NY. unsatisfactory In all of these processes reaction at the silicon-chlorine boiling trifunctional impurity. The processes shown in bond takes place in preference to reaction in another por Equations 3 and 4 illustrate similar difficulties arising tion of the molecule. Many other examples will be ap from Substantially identical boiling points of compounds parent to those skilled in the art. to be separated. In addition to the reactivity of chlorosilanes which Various approaches have been tried to overcome one causes undesirable side reactions to take place, chloro or more of these difficulties. One is to convert the chloro silanes have other shortcomings as intermediates for the silane to the corresponding silicone thus removing the preparation of organo-functional chlorosilane monomers. offending group. One can then carry out a number of Thus, it is well known that related di- and trifunctional reactions without interfering side reactions as shown in chlorosilanes have boiling points that are separated by the equations that follow only a few degrees. In some synthetic procedures this 50 (N-1) fact makes it difficult to obtain products of high purity. A This is illustrated in the examples shown below. GNEI -- C-(CH2)3Si(CH3)O - (M-1) bSiCl3 - MeSiCl3 - bMeSiCl2 - MeSiCl3 IGNH(CEI) 3SiMe O - GNHC) 2000 2000 (N-2) (M-2) 55 MeSiHC - ClsSI -- CH-CH-CH2-CN - 42 37 GOEI - (Cé-(CH) SIMeo). --> Cl3Si(CH2)3CN - Cl2SiMe (CH)3CN (GOOC (CII)SiMeO) -- HC 245 245° While competing side reactions are eliminated in this (M-3) SiCl3 -- MeMgX - d.MeSiCl2 - MgXCl way certain disadvantages are still present. Because 200 200° 60 many silicones cannot be readily distilled, purification re (M-4) mains a problem. In addition, the reactivity of polymeric Cl3Sili -- MeSiHCl2 - H-CeC-H --> siloxanes is greatly reduced in certain cases so that satis 37o 42 factory reaction does not take place. Specific instances CH=CHSiCl3 and CH2=CE--SiMeC. of this are shown below. 92° g20 65 The process shown in Equation 1 is complicated by the (O-1) (MeSiHO)--C=C-G->poor reaction fact that one of the reactants, pSiCl3 and one of the (O-2) I products, pMeSiCl2 are difficult to separate because their (NC (CH2)3SiMeO) - poor reaction boiling points are virtually identical. In the process Another limitation is that it is frequently desirable for represented by Equation 2 it is difficult to obtain the 70 certain applications to have the silicon compounds in desired product, gamma - cyanopropylmethyldichlorosil a monomeric rather than polymeric form. ane, in the state of high purity necessary for elastomer Another approach that has been used to overcome preparation because methyldichlorosilane is usually con certain disadvantages of using halosilanes is conversion taminated by minor amounts of trichlorosilane whose to another group such as alkoxy. This method has shown presence results in the formation of undesirable close 75 Some promise and is useful in certain synthetic procedures. 3,128,297 3 4. (P-1) MeSiH(OEt)--HC=CH-CHNH-> Equations S and T illustrate that the purification prob MeSi(OEt) 2CCH2) 3NH2 lems that exist in the synthesis of certain chlorosilanes (P-2) Cl(CH2)Si(OEt)--2GNH-> are simplified when fluorosilanes are employed. The im GNH(CH2)Si(OEt) --GNHC1 purity ClSiH often present in MeSiHCl2 gives an im 5 purity product which is difficult to separate. The cor As a general approach, however, the use of alkoxy responding fluorosilane impurity, FSiH, boils at -70 silanes in place of halosilanes has certain drawbacks. C. and is easily removed from the MeSiHF starting ma These are: (1) lowered reactivity for certain reactions terial. Equations U illustrate still another reaction where Such as in SiH additions to olefins; (2) for certain ap the use of a fluorosilane in place of a chlorosilane allows plications, for example the preparation of elastomers, IO a desired reaction to take place. In Equation V, the ready the tendency for alkoxysilanes to hydrolyze incompletely conversion of a fluorosilane to a chlorosilane is shown. would be undesirable; and (3) converting a halosilane Heretofore the possible advantages in the use of fluoro to an alkoxysilane generally raises the boiling point mak silanes as intermediates in the production of organo-func ing the purification of some monomers by distillation tional chlorosilanes or other halosilanes were of little use difficult. because of the difficulty in converting the fluorosilanes to Our discovery of an efficient and rapid base catalyzed 5 chlorosilanes. These disadvantages included difficulty in redistribution process makes it possible to employ fluoro obtaining complete hydrolysis of fluorosilanes to siloxanes silanes as intermediates in the production of other halo when the desired final product was an organo-functional silanes. By this method, many organo-functional halo polysiloxane. Also attempts to prepare fluorosilanes (for silanes, particularly chlorosilanes, can be prepared effi 20 use as intermediates) from chlorosilanes resulted in loss ciently and in high yield which would be difficult or im of fluorine and exceedingly slow reaction thus making possible to prepare by known methods. the conversion process exceedingly inefficient. The advantages of the use of fluorosilanes as intermedi Thus, this invention makes it possible to (1) easily pre ates where it is desired to carry out chemical reactions pare fluoro-silicon compounds for use as intermediates on the organic portion of an organo-silicon compound 25 and (2) readily reconvert a fluorosilane intermediate to are the following: (1) fluorosilanes are much less reac a chlorosilane or other halosilane. tive than the corresponding chlorosilanes or other halo In a particularly preferred embodiment of this inven silanes and interfering side reactions are minimized; (2) tion the fluorosilane and chlorosilane used in converting it is easier to separate related di- and trifunctional fluoro the organo-functional fluorosilane to an organo-functional silanes because of the greater spread in boiling points; 30 chlorosilane may be so selected that a highly efficient con (3) the lower boiling points of fluorosilanes simplifies tinuous process for producing organo-functional chloro distillation; (4) fluorosilanes can be converted to chloro silanes results. This preferred cyclic process is illustrated silanes or other halosilanes by a redistribution reaction. Specific examples where the above properties can be by the following examples. The Equations W, X and Y used to advantage are shown in the equations that follow. below show only the principal reaction products. 35 (W-1) dSiCl3 - Na2SiF6 -) (SiF3 (Q-) H2SO4 gbSiCl3 -- HNO3 --> O2NbSiCl3 (W-2) HSO4 CHCls pSi3 - FINO3 - ONobSiF3 (Q-2) H2SO4 (W-3) NObSiF3 - d SiCl3 basic NOpSiCls -- jSiFs gbSiF3 - EINO3 --> O2NbSiF3 catalystaSic In Equations Q, nitration of phenyltrichlorosilane re- 40 (X-1) ClibuSiMe Cls -- Na2SiF6 - ClibuSiMeF Sults in very low yields of nitrophenyltrichlorosilane while (X-2) DMF nitration of phenyltrifluorosilane gives a quantitative yield CliBuSiMeF. -- Na CN - CNiBuSiMeF. of nitrophenyltrifiuorosilane. The low yield of nitro (X-3) phenyltrichlorosilane is due to hydrolysis and other side CNBuSiMef -- ClibuSiMeCla. --> Basic reactions. In addition, an organic solvent such as chloro 45 catalyst form is required to reduce hydrolysis and reaction be tween the chlorosilane and sulfuric acid. CNiBuSiMe Cls -- ClibuSiMeF (Y-1) MeSiHCl -- bSiF3 Basic MeSHF -- SiCl3 (R-1)R-1 DMF aSC catalyst CCH-CHCH3-CH2SiMeCl; -- NaCN -) polymer 50 (R-2)R-2 DMF (Y-2) ClCHCHCH3CHSiMef -- NaCN - MeSiHF -- CH=CH-CH-CN - F Si(Me) (CH2)3CN (Y-3) -CN-CH-CHCH3CH2-SiMeF NC(CH2)3SiMeF -- MeSiHCl --> Basic Equations R show that a chloroalkylchlorosilane can- 55 catalyst not be made to react satisfactorily with sodium cyanide NC (CH)3SiMeC - MeSi EIF in dimethylformamide because the chlorosilane reacts As shown by the equations of these examples a chloro preferentially with the solvent causing its decomposition. silane starting material is recovered as an organo-func The chloroalkylfluorosilane does react satisfactorily with tional chlorosilane. The fluorosilane intermediate is a sodium cyanide because fluorosilanes are much less reac- 60 reactant in Equations W-2, X-2 and Y-2 and is a product tive with dimethylformamide. in Equations W-3, X-3 and Y-3. Thus, the fluorosilane (S) intermediate may be continuously recycled thus conserving Meg42 Cyclish)7 + CH=CH-CH.CN - the fluorine in the system and eliminating the necessity MeSiCl2(CH2)3CNICISi(CII)3CN) 65 of preparing large quantities of fluorosilane each time 245° 245° the chemical reactions such as those indicated in Equa (T) Mes:F. -- CH2=CH-CH-CN - MeSiF2(CH2)3CN tions W-2, X-2 and Y-2 above are carried out. -35 As is also illustrated by Examples W, X and Y above (U-1) CICO(CH) SiMeCl--GOH-> the initial batch of fluorosilane may be prepared by any GOOC(CH2)2SiMe(OEt) to convenient method. In Examples W and X the fluoro (U-2) ClCO(CH2)SiMeF--GOH-> silane is prepared using an alkali metal fluorosilicate as GOOC-(CH2)SiMeF the source of fluorine and in Example Y the redistribu tion process of this invention is used in the initial prepara (V) G3N gamma-NC(CH2)3SiMeF2 -- SiCl, --> tion of the fluorosilane intermediate. gamma-NC(CH2)3SiMe Cls -- SiFi > 75 Thus, the redistribution process of this invention can 3,128,297 S 8 be employed in the preparation of organo-functional the reaction products: 1141 grams (6.0 moles) of phenyl halosilanes which may be represented by the formula: methyldichlorosilane, 1504 grams (8.0 moles) of Na2SiF6 and 750 milliliters of tetrahydronaphthalene. The reaction mixture was heated at its boiling point with wherein R, Y, have the meanings defined hereinabove, Q 5 stirring under an inert atmosphere of nitrogen. Crude is a halogen different from fluorine, preferably chlorine, phenylmethyldifluorosilane was removed by fractional and i is an integer having a value from 1 to 3. distillation over a 3 hour period. The crude product As a first step in producing the halosilane of Formula was redistilled to yield 802 grams of pure phenylmethyl Z, a fluorosilane is prepared which may be represented difluorosilane having a boiling point of 143 to 144.5 C. by the formula: O Nitration of phenyimethyldifluorosilane.-The follow ing were placed in a flask fitted with stirring mechanism, (AA) thermometer and dropping funnel for introducing the acid reactants: 474.5 grams (3.0 moles) of phenylmethyl wherein Y, R and i have the meanings defined herein difluorosilane and 1 liter of chloroforin. In the dropping above. This fluorosilane may be prepared by any con 5 funnel was placed a mixture of 315 grams (4.5 moles) venient method and must of course have the same func of 90 percent fuming nitric acid and 700 grams of con tionality (that is, the same number of silicon-halogen centrated sulfuric acid. The mixed acids were added to bonds) as the desired product of Formula Z. the flask over a period of 20 to 40 minutes while the This fluorosilane is then converted to the desired temperature of the reaction mixture was maintained be product of formula Z by the redistribution process of 20 tween 15° C. and 30° C. by means of an ice bath. After this invention. In this step, the compound of For the addition of acid was complete the reaction mixture mula AA is mixed with (a) a halosilane and with (b) was stirred for 30 minutes at temperatures below 30° C. an operable redistribution catalyst as defined hereinabove. The final reaction mixture consisted of an acid layer and This halosilane may be represented by the formula: an organic layer which were separated in a separatory (BB) (Z-R-)SiO4 25 funnel. The acid layer was discarded. Chloroform was removed from the organic layer under reduced pressure wherein R, Q, and i have the meanings defined herein and the residue was fractionally distilled under reduced above and Z is a group different from Y. Z can be hy pressure to yield nitrophenylmethylidifluorosiiane having drogen, fluoro, chloro, bromo, iodo, cyano, a boiling point of 75 C. at a pressure of 0.4 millimeter 30 of mercury. -COO G, -O G, -NG Redistribution reaction.-The following were placed -C-NG, in a 2 liter flask fitted with means for fractionally dis or nitro, and G has the meaning defined hereinabove. tilling the reaction products: 448 grams (2.2 moles) of The redistribution reaction is then carried out as de nitrophenylmethylidifiuorosilane, 630 grams (3.3 moles) scribed hereinabove and is driven to completion by re 35 of phenylmethyldichlorosilane and 4.5 grams of tri-n- moving the fluorosilane reaction product having the for butylamine. The reaction mixture was heated at its boil mula: ing point and relatively low boiling products were frac tionally distilled at atmospheric pressure. The reaction (CC) (Z-R-) SiF4 products were further fractionally distilled at reduced wherein Z, R and i have the meanings defined herein 40 pressure and 261 grams of nitrophenylmethyldichloro above. The desired organo-functional halosiiane of For silane having a boiling point of 85 C. to 95 C. over a mula Z can then be recovered in high yield from the re pressure range of 0.2 to 0.5 millimeter of mercury were suiting reaction mixture. recovered. In the preferred continuous process for producing an EXAMPLE 13 organo-functional chlorosilane of Formula Z, the first step Redistribution of Nitrophenyltrifluorosilane involves converting a fiuorosilane of Formula CC to a fi/ith Phenyltrichlorosilane fluorosilane of Formula AA by appropriate chemical reac tions. These chemical reactions depend upon the nature Preparation of phenyltrifluorosilane. The following of the Y and Z groups in the compounds of Formulas AA were placed in a 5 liter flask equipped with stirrer, ther and CC and the choice of reactions and reaction condi mometer and means for fractionally distilling the reac tions can be easily made by one skilled in the chemistry tion products: 750 milliliters of tetrahydronaphthalene of organo-silicon compounds. Several such conversions solvent, 2260 grams (12.0 moles) of Na2SiF6 and 1270 are detailed in the illustrative examples which follow. grams (6.0 moles) of phenyltrichlorosilane. The reac The fluorosilane of Formula CC may be prepared initially tion mixture was stirred and heated at its boiling point by any convenient method. The fluorosilane of Formula under an inert atmosphere. Crude phenyltrifluorosilane AA is then mixed with a chlorosilane of Formula BB and having a boiling point of 90° C. to 110° C. was removed the redistribution reaction driven to completion as de from the reaction mixture by fractional distillation over scribed in the two next preceding paragraphs. The com a 3 hour period. The crude product was redistilled to pound of Formula CC which is removed in driving the give 860 grams of pure phenyltrifluorosilane having a reaction to completion can be recycled and used in pre 60 boiling point of 101° C. to 103° C. paring the fluorosilane of Formula AA. In this preferred Nitration of phenyltrifluorosilane-Following the pro continuous process, the compounds of Formulas AA, BB cedure described in detail in the second paragraph of Ex and CC all have the same functionality. ample 12, phenyltrifluorosilane was nitrated to produce The following additional examples illustrate the use nitrophenyltrifluorosilane having a boiling point of 56 of the redistribution process of this invention in the prep 65 C. at a pressure of 1.7 millimeters of mercury. aration of organo-functional halosilanes, including the Redistribution reaction.-The following were placed in preferred cyclic process for producing chlorosilanes. a 1 liter flask fitted with means for fractionally distilling reaction products: 460 grams (2.2 moles) of nitrophenyl EXAMPLE 12 trifluorosilane, 700 grams (3.3 moles) of phenyltrichloro 70 silane and 5 grams of tri-n-butylamine. The reaction Redistribution of Nitrophenylmethyldifluorosilane mixture was heated at its boiling point and a fraction With Phenylmethyldichlorosilane comprising mainly phenyl-, mixed chloro- and fluoro Preparation of phenylmethyldifluorosilane.--The fol silanes and having a boiling point of 103° C. to 130° C. lowing were placed in a flask equipped with stirring mech at atmospheric pressure was collected over a period of anism, thermometer and means for fractionally distiling 75 about one hour. The reaction products were further 3,128,297 17 18 fractionally distilled at reduced pressure and 348 grams EXAMPLE 16 of nitrophenyltrichlorosilane having a boiling point of 98 C. to 128° C. in the pressure range of 0.2 to 1.7 Redistribution of Gamma-Cyanopropylmethyldifluorosil millimeters of mercury were recovered. This represents ane With Methyldichlorosilane about an 80 percent conversion of nitrophenyltrifluoro 5 Addition of methyldifluorosilane to allyl cyanide-The silane to nitrophenyltrichlorosilane. following were placed in a 200 milliliter pressure vessel: By a careful fractional distillation of the relatively low 83 grams (1.24 moles) of allyl cyanide, 55 grams of boiling reaction products phenyltrifluorosilane can be re methyldifluorosilane and 0.00003 mole of H2PtCl6 in 1 covered and recycled for use in the nitration step de milliliter of ethanol. The pressure vessel was sealed and scribed in the second paragraph of this example. O heated at 160° C. with shaking for 3 hours. The reaction products were separated by fractional distillation and 88 EXAMPLE 14 grams of crude product were obtained. The crude ma" Redistribution of Bis(Nitrophenyl) Difluorosilane terial was redistilled at atmospheric pressure to produce With Bis(Phenyl) Dibromosilane gamma-cyanopropylmethyldifluorosilane having a boiling 5 point of 195.3° C. Following the procedures detailed in Example 13, bis Redistribution reaction.-Following the procedures of (phenyl) dibromosilane is reacted with Na2SiF6 to pro Example 15, a mixture of methyldichlorosilane, gamma duce bis(phenyl) difluorosilane which is thereafter ni cyanopropylmethyldifluorosilane and tri-n-butylamine trated to yield bis(nitrophenyl) difluorosilane. A mixture catalyst are heated and fractionally distilled to yield of bis(nitrophenyl)-difluorosilane, bis(phenyl) dibromo 20 methylidifluorosilane and gamma-cyanopropylmethyldi silane, and tri-n-hexylamine catalyst is then heated and chlorosilane. The methyldifluorosilane produced in the fractionally distilled to produce bis(nitrophenyl) dibro redistribution reaction can be recycled and used in the pro mosilane and bis(phenyl) difluorosilane. The latter duction of the fluorosilane intermediate as described in compound can be recycled and nitrated to yield additional the first paragraph of this example. bis(nitrophenyl) difluorosilane for use in the redistribu 25 In another preferred embodiment of the present in tion step. vention the base catalyzed silicon-halogen bond redistri EXAMPLE 15 bution process of this invention can be used in the purifi cation of chlorosilane mixtures, bromosilane mixtures, or Redistribution of Gamma-Cyanoisobutylmethyldifluoro iodosilane mixtures. silane With Gamma-Chloroisobutylmethyldichloro 30 For example, it is frequently difficult to obtain chloro silane silanes in high purity because related higher functional Preparation of gamma-chlorisobutylmethyldifluoro chlorosilanes have boiling points separated by only a few silane-The following were placed in a reaction flask degrees. For example, MeSiCl3, B.P. =70° C.; MeSiCl3, fitted with stirring means, thermometer and means for B.P.-66 C. and pSiCl, B.P.=201 C.; pMeSiCl2, fractionally distilling the products: 383 grams (2.0 moles) B.P.s 204° C. This problem is of particular importance of gammachlorosiobutylmethyldichlorosilane, 500 grams in the preparation of elastomers where the presence of (2.7 moles) of NaSiF6 and 350 milliliters of tetrahydro very small quantities of trifunctional impurities is unde naphthalene. The reaction mixture was heated at its boil sirable. Functionality is, as stated hereinabove, defined ing point and crude product was recovered by fractional in terms of the number of silicon-halogen bonds in the distillation over a 3 hour period. The crude product 40 organo-silicon compound. was redistilled to yield pure gamma-chlorisobutyldi By way of illustration, a number of methods have been fluorosilane having a boiling point of 143 C. to 144 C. heretofore disclosed for purifying chlorosilanes. These Preparation of gamma-cyanoisobutylmethyldifluorosil methods involve conversion of the chlorosilane to the cor ane.-The following were placed in a reaction flask fitted responding esters which are then separated by distillation, with stirring means, thermometer and means for frac 45 by selective reaction of higher functional impurities with tionally distilling the reaction products: 75 grams (1.5 limited amounts of water and by removal of certain im moles) of sodium cyanide, 2 grams of potassium iodide purities such as silicon tetrachloride or trichlorosilane by and 200 milliliters of dimethylformamide. This mixture complex formation with tertiary amines. was heated at its boiling point to drive off any water pres A procedure has now been discovered for the purifica ent. The mixture was then cooled and 180 grams (1.04 tion of halosilanes which employs fluorosilanes as inter moles) of gamma-chloroisobutylmethyldifluorosilane was mediates and which makes use of the redistribution re added. This mixture was then heated to its boiling point action of the present invention. By this procedure, halo for 2 hours. After cooling to 35° C., 150 milliliters of silanes are purified by the selective removal of higher anhydrous diethyl ether was added and the entire mixture functional halosilanes as fluorosilanes. was filtered. The filtered mixture was then fractionally 55 According to the improved purification process of the distilled to give a crude product boiling in the range from present invention a halosilane admixed with halosilane 33 C. at 4.0 millimeters pressure to 50° C. at 1.3 milli impurities of higher functionality can be purified by add meters pressure. The crude product was redistilled at ing to the mixture. a fluorine-containing compound and a atmospheric pressure to yield 82 grams of pure gamma suitable basic catalyst as hereinbefore described. Silicon cyanoisobutylmethylidifluorosilane having a boiling point 60 fluorine bonds are formed and a redistribution of the of 199.5 C. 200 C. at 750 millimeters pressure. silicon-fluorine and other silicon-halogen bonds takes Redistribution reaction.--The following were placed in place. The most volatile of the resulting fluoro-silicon a 500 milliliter flask fitted with means for fractionally dis compounds are then removed from the system. The most tilling the products: 80 grams (0.49 mole) of gamma volatile fluoro-silicon compound is formed from the halo cyanoisobutylmethyldiffuorosilane, 155 grams (0.74 mole) 65 silane having the highest functionality. Thus, by adding of gamma-chloroisobutylmethyldichlorosilane and 1.6 to the halosilane mixture sufficent fluorine-containing grams of tri-n-butylamine. The reaction mixture was compound to provide at least one mole of available fluo then heated to its boiling point and the products frac rine per mole of silicon-halogen bonds in the higher func tionally distilled to yield pure gamma-cyanoisobutylmeth tional halosilane impurities these impurities can be com yldichlorosilane having a boiling point of 63 C. at 0.3 70 pletely removed from the system. The desired halosilane millimeter pressure. The gamma-chloroisobutylmethyl can be readily obtained from the resulting reaction mix difluorosilane produced in the redistribution reaction can ture in high purity by distillation. be recycled and used to produce additional quantities of For example, an initial chlorosilane mixture may con gamma-cyanoisobutylmethylidifluorosilane as described in sist of trimethylchlorosilane (boiling point 57 C.) as the the second paragraph of this example. 75 main component and silicon tetrachloride (boiling point 3,128,297 9 20 58 C.) as an impurity. To this system can be added The use of alkali metal fluorosilicates and metal phenyltrifluorosilane (boiling point 102° C.) in a ratio fluorides to introduce silicon-fluorine bonds into the sys of about 1.33 moles of phenyltrifluorosilane per mole of tem does not have the disadvantages discussed herein silicon tetrachloride impurity and a catalytic amount of above with reference to using these materials in pre tri-n-butylamine. By heating and distilling the resulting paring fluorosilanes. In the purification process, only a reaction mixture silicon tetrafluoride gas is removed and relatively small percentage of the silicon-chlorine bonds the resulting reaction mixture contains trimethylchloro are converted to silicon-fluorine bonds by this process, silane and phenyltrichlorosilane (boiling point 201 C.), and only relatively small amounts of solid materials the latter compound being derived from the phenyltri are introduced into the system. fluorosilane originally added. The trimethylchlorosilane 0 It is preferable to use an excess of fluorine containing can then be easily recovered by fractional distillation in compound over the amount required to furnish one mole highly purified form. of available fluorine per mole of silicon-halogen bonds The halosilanes which can be purified by the process of in the mixture. The magnitude of the excess is not criti the present invention may be represented by the formula: cal, but an excess varying from 5 to 10 percent of the mole for mole amount when the halosilane impurity con (DD) R h tent is in the order of 8 to 10 weight percent of the halo (Y-R-)SiO4--, silane mixture to 200 percent of the mole for mole wherein R, Y, G (included in the definition of Y), Q amount when the impurity content is less than one percent and R have the meanings defined hereinabove with refer has been found most preferable. ence to Formulas B and Z, g is an integer having a value 20 In a preferred form of the purification process of from 1 to 3, h is an integer having a value from 0 to 1, this invention the source of fluorine is a fluorosilane rep and the sum of g and h is never greater than 3. resented by the formula: The higher functional halosilane impurities may be represented by the formula: (FF) R’ (EE) Ru 25 (Z-R-) Sig-t- wherein R has the meaning defined with reference to wherein R, Y, G (included in the definition of Y), Q and Formula B hereinabove, Z has the meaning defined with R have the meanings defined hereinabove with reference reference to Formula BB hereinabove, R' is selected from to Formulas B and Z, t is an integer having a value from the class consisting of hydrogen, the vinyl group and 0 to 2, u is an integer having a value from 0 to 1 and 30 Z-R- groups, and t and u have the meanings defined the sum of t and u is never greater than 2. That is, the with reference to Formula EE hereinabove. Such fluoro compounds to be purified (Formula DD) can be mono-, silanes must, of course, have higher boiling points than di- or trifunctional halosilanes, while the impurities of any of the halosilanes in the reaction mixture to be puri Formula EE can be di-, tri-, or tetrafunctional halosilanes. fied. Examples of the chlorosilanes which can be purified The operable redistribution catalysts are the tertiary by this process include all those which can undergo the amine, tri(monovalent hydrocarbon group) phosphines chlorosilane-fluorosilane redistribution reaction as dis and silylamines described in detail hereinabove. The cussed hereinabove. Generally, this process may be em amount of catalyst, reaction temperatures and times are ployed to purify a chlorosilane which is contaminated also the same as those discussed hereinabove with ref by one or more higher functional, close boiling impurities. 40 erence to the general base catalyzed redistribution reaction In the examples of systems that follow which may be of this invention. purified by this process, the main component is listed first, In carrying out the halosilane purification process of, followed by the impurity or undesired component. These this invention, the impure mixture (whose major com Systems include by way of exemplification and not limita ponent is a halosilane of Formula DD and whose minor tion 45 components are higher functional halosilanes of Formula EE) is combined with a source of fluorine and a basic cata dimethyldichlorosilane-methyltrichlorosilane; lyst. The combined mixture is then heated to a tem phenylmethyldichlorosilane-phenyltrichlorosilane; perature sufficiently elevated to cause the redistribution diphenyldichlorosilane-bis-trichlorosilylbenzene; reaction to take place, preferably a temperature between vinylmethyldichlorosilane-vinyl-trichlorosilane; 50 about -20° C. and about 200 C. When the source of diethyldichlorosilane-ethyltrichlorosilane; fluorine is an alkali metal fluorosilicate or a metal fluoride, methyldichlorosilane-trichlorosilane; these compounds first of all react with silicon-halogen trimethylchlorosilane-silicon tetrachloride; bonds present in the mixture to form silicon-fluorine gamma-cyanopropylmethyldichlorosilane-gamma-cyano bonds. Redistribution then takes place between the propyltrichlorosilane; 55 silicon-fluorine and other silicon-halogen bonds. The diphenylmethylchlorosilane-diphenyldichlorosilane; most volatile compounds in the redistributed mixture are gamma-chloroisobutylmethyldichlorosilane-gamma the fluorosilanes corresponding to the higher functional chloroisobutyltrichlorosilane; halosilane impurities, that is, fluorosilanes represented by bis-dichloromethylsilylbenzene-bis-trichlorosilylbenzene; the formula: bis-dimethylchlorosilylethylene-bis-dichloromethylsilyl 60 ethylene and the like. (GG) Ru Similar mixtures of bromosilanes or iodosilanes can (Y-R-) SiF 4-i- also be purified by the above described purification process. wherein Y, R, R, t and u have the meanings defined with The sources of fluorine which can be employed are reference to Formula EE hereinabove. The redistribution alkali metal flurorosilicates, such as, Na2SiF6 and KSiF6, 65 reaction is driven to completion by removing the fluoro metal fluorides such as, silver fluoride, cobalt fluoride, silanes of Formula GG from the reaction mixture and boron fluoride, hydrogen fluoride, antimony fluoride, cal the halosilane of Formula DD is then recovered from the cium fluoride, sodium fluoride and the like and fluoro resulting reaction mixture. silanes having higher boiling points than the halosilanes When the source of fluorine is an alkali metal fluoro in the mixture. These compounds react with the com 70 silicate or metal fluoride the resulting reaction mixture pounds in the mixture to be purified, with the formation of typically contains the halosilane of Formula DD, the cata silicon-fluorine bonds, in the preferred temperature range lyst and solid residues, all of which are readily separable. from about -20° C. to about 200° C. Higher tempera When the source of fluorine is a fluorosilane, the resulting tures can also be employed but without any substantial reaction mixture typically contains the halosilane of increase in yield or rate of reaction. Formula DD, the catalyst, and relatively high boiling 3,128,297 21 22 halosilanes derived from the fluorosilane. Again a sepa The purified gamma-cyanopropylmethyldichlorosilane ration is readily carried out. was used to prepare a gamma-cyanopropylmethylsilicone Selecting a fluorosilane having a higher boiling point modified dimethyl silicone elastomer. The properties of than the halosilanes in the original mixtures is necessary the cured elastomer indicated that the gamma-cyanopro in order that the halosilane derived from it as a result of pylmethyldichlorosilane used in its preparation was sub the redistribution reaction will boil appreciably higher stantially free from trifunctional impurities. than the halosilane to be purified. The following examples are illustrative of the embodi EXAMPLE 21 ment of the present invention wherein the novel base The following were placed in a 1 liter flask fitted with catalyzed silicon-halogen bond redistribution process is means for fractionally distilling the reaction mixture: 500 used in the purification of halosilane mixtures. grams of methyldichlorosilane, 59 grams of trichloro silane, 162 grams of phenyltrifluorosilane, 1 gram of tri EXAMPLE 17 n-butylamine and 1 gram of N,N-diethylaniline. The re The following were placed in a 500 milliliter flask action mixture was chilled to 2° C. to 5 C. and main fitted with means for fractionally distilling the reaction tained at this temperature for about 3 hours during which products: 102 grams (0.404 mole) diphenyldichloro time gaseous fluorosilanes were evolved. The reaction silane, 11 grams (0.03 mole) bis(trichlorosilyl)benzene, mixture was then warmed to 20 C. over a half-hour pe 21 grams (0.11 grams) Na2SiF6 and 0.5 gram tri-n-heptyl riod. The reaction mixture was then fractionally distilled amine. The reaction mixture was heated at its boiling at atmospheric pressure. The product fraction having point and fractionally distilled. The first fraction boil a boiling point of 40.5 C. to 40.8° C. was identified as ing at 125 C. at atmospheric pressure was identified as 20 methyldichlorosilane containing only 0.11 percent of tri bis(trifluorosilyl)benzene. This represented almost com chlorosilane. plete removal of the bis(trichlorosilyl)benzene impurity EXAMPLE 22 from the reaction mixture. The following were placed in a 500 milliliter flask fitted 25 with means for fractionally distilling the products: 200 EXAMPLE 1.8 grams of vinylmethyldichlorosilane, 12 grams of vinyl The following were placed in a 500 milliliter flask trichlorosilane, 48 grams of phenyltrifluorosilane and 2 fitted wtih means for fractionally distilling the reaction grams of N,N-diethylaniline. Some methyltrichlorosilane products: 103 grams (0.95 mole) of trimethylchloro impurity was also present. The reaction mixture was silane, 14.3 grams (0.084 mole) of silicon tetrachloride, 30 maintained at room temperature overnight during which 25 grams (0.154 mole) of phenyltrifluorosilane and 1 time a slow evolution of gas, principally vinyltrifluoro gram of tri-n-heptylamine. An immediate evolution of silane, took place. The reaction mixture was then heated gas, principally silicon tetrafluoride, took place. After at its boiling point and fractionally distilled at atmos the gas evolution had subsided the reaction mixture was pheric pressure. Purified vinylmethyldichlorosilane hav fractionally distilled at atmospheric pressure. The last 35 ing a boiling point of 92.8 C. was recovered. A sample traces of fluorosilane (trimethylfluorosilane) were re of the purified material was analyzed for impurity content moved in a fraction boiling at 54° C. to 57° C. Purifi and compared with the impurity content of the mixture cation of the remaining reaction mixture by fractional distillation was continued and 70 grams of purified prod with the following results: uct boiling at 57.0° C. to 57.5 C. was recovered. The 40 purified product was analyzed and was found to consist Sample Original Purified Sample of trimethylchlorosilane containing less than 0.1 percent Mixture silicon tetrachloride impurity. MeViSiCl2 (percent).------94.9 100. ViSiCl3 (percent).------4.9 Not detected (less EXAMPLE 1.9 than 0.1). 45 MeSiCl3 (percent).------0.24 Not detected (less The following were placed in a 1 liter flask fitted with than 0.1). means for fractionally distilling the reaction mixture: 99 grams (0.47 mole) of phenyltrichlorosilane, 406 grams (2.12 moles) of phenylmethyldichlorosilane, 167 grams EXAMPLE 23 (0.89 mole) of sodium fluorosilicate and 1.5 grams of 50 The following were placed in a 1 liter flask fitted with N,N-diethylaniline. The reaction mixture was heated at means for fractionally distilling the products: 436 grams its boiling point and silicon tetrafluoride gas was evolved. of dimethyldichlorosilane, 4.4 grams of methyltrichloro Gas evolution subsided after about 2 hours and the re silane, 22 grams of phenyltrifluorosilane and 4.5 grams of maining reaction products were fractionally distilled at N,N-diethylaniline. The reaction mixture was heated atmospheric pressure. About 85 percent of the phenyl at its boiling point and low boiling fluorosilanes were re trichlorosilane originally present in the chlorosilane mix moved. The remaining chlorosilanes were then frac ture was removed as phenyltrifluorosilane. tionally distilled at atmospheric pressure. The purified dimethyldichlorosilane contained about only 0.1 percent EXAMPLE 2.0 of trifunctional impurity while the impure mixture con The following were placed in a 1 liter flask fitted with 60 tained about 0.97 percent methyltrichlorosilane. The means for fractionally distilling the products: 500 grams low boiling fluorosilanes removed consisted primarily of (2.75 moles) of gamma-cyanopropylmethyldichlorosil methyltrifluorosilane. ane, 12.5 grams (0.062 mole) of gamma-cyanopropyl EXAMPLE 24 trichlorosilane, 26 grams (0.138 mole) of sodium fluoro silicate and 0.5 gram of 2,2'-dipyridyl. The reaction mix 65 Following the procedures of Example 23, dimethyl ture was heated at its boiling point and silicon tetrafluo dibromosilane containing three weight percent methyl ride gas was evolved. At this point an additional 25 tribromosilane is purified by adding phenyltrifluorosilane grams (0.035 mole) of sodium fluorosilicate and 0.5 and N,N-diethylaniline, heating the resulting mixture, and gram of 2,2'-biquinolyl was added and the reaction mix recovering the dimethyldibromosilane containing less ture again heated at its boiling point to drive of additional 70 than one weight percent methyltribromosilane by frac quantities of silicon tetrafluoride. The resulting reaction tional distillation. mixture was fractionally distilled at atmospheric pressure. What is claimed is: A fraction boiling at 242 C. was identified as substan 1. A process for the redistribution of silicon-halogen tially impurity-free gamma-cyanopropylmethyldichloro bonds in organo-silicon compounds which comprises form silane. ing a reactive mixture consisting of (1) at least one or 3,128,297 23. 24. gano-silicon compound selected from the class consisting wherein R, Y and X have the meanings defined herein of (a) silanes represented by the formula: above, r is an integer having a value from 1 to 3, and s is an integer having a value from 2 to 10, and (2) a basic catalyst selected from the class consisting of tertiary amines wherein all three normal valencies of the nitrogen wherein R is a divalent hydrocarbon group, Y is a group atoms are bonded to carbon atoms of hydrocarbon moi Selected from the class consisting of hydrogen, fluoro, eties, tri(monovalent hydrocarbon group) phosphines, and chloro, bromo, iodo, cyano, silylamines represented by the formula:

-COO G, -NG, -O G, O -C-G, -C-NG wherein G has the meaning defined hereinabove, and m is and nitro, G is a monovalent hydrocarbon group, R is an integer having the value of zero to 3, there being pres selected from the class consisting of hydrogen, the vinyl ent in said reactive mixture at least one silicon-chlorine group, and Y-R-groups, X is a halogen, e is an integer bond and at least one silicon-fluorine bond, and heating having a value from 0 to 3, f is an integer having a value said mixture to a temperature sufficiently elevated to cause from 0 to 1 and the sum of e and f is never greater than 3. said redistribution to take place. (b) linear polysiloxanes represented by the formula: 3. A process for the redistribution of silicon-halogen bonds in organo-silicon compounds which comprises form ing a reactive mixture consisting of (1) at least one 20 organo-silicon compound represented by the formula: wherein R, Y and X have the meanings defined herein R". above and y is an integer having a value from 1 to 10,000, (Y-R-) Six-3-f and (c) cyclic polysiloxanes represented by the formula: wherein R is a divalent hydrocarbon group containing 25 from 1 to 17 carbon atoms, Y is a group selected from the class consisting of hydrogen, fluoro, chloro, bromo, iodo, Cyano, O O wherein R, Y and X have the meanings defined herein -COO G, -NG, -O G, : above, r is an integer having a value from 1 to 3, and s is -C-G, an integer having a value from 2 to 10, and (2) a basic catalyst selected from the class consisting of tertiary and nitro, G is a monovalent hydrocarbon group con amines wherein all three normal valencies of the nitrogen taining from 1 to 10 carbon atoms, R is selected from atoms are bonded to carbon atoms of hydrocarbon moi the class consisting of hydrogen, the vinyl group, and eties, tri(monovalent hydrocarbon group) phosphines, and 35 Y-R-groups, X is selected from the class consisting of silylamines represented by the formula: fluorine and chlorine, e is an integer having a value of from 0 to 3, f is an integer having a value from 0 to 1 and the sum of e and f is never greater than 3, and (2) a wherein G has the meaning defined hereinabove, and n is tertiary amine catalyst, all three normal valencies of the an integer having the value of zero to 3, there being pres 40 nitrogen atoms in said amine being bonded to carbon ent in Said reactive mixture at least one silicon-fluorine atoms of hydrocarbon moieties, there being present bond and at least one other different silicon-halogen bond, in said reactive mixture at least one silicon-chlorine bond and heating said mixture to a temperature sufficiently ele and at least one silicon fluorine bond, and heating said Wated to cause said redistribution to take place. mixture to a temperature between about -20° C. and 2. A process for the redistribution of silicon-halogen about 200 C. to cause said redistribution to take place. bonds in organo-silicon compounds which comprises form 45 4. A process in accordance with claim 3 wherein said ing a reactive mixture consisting of (1) at least one or redistribution reaction is carried out in an inert organic gano-silicon compound selected from the class consisting solvent. of (a) silanes represented by the formula: 5. A process in accordance with claim 3 wherein said tertiary amine catalyst is selected from the group con R", 50 sisting of tri-n-butylamine, tri-n-hexylamine, tri-n-heptyl (Y-R-)eSix-- amine, N,N-diethylaniline and 2,2'-dipyridyl. wherein R is a divalent hydrocarbon group, Y is a group 6. The process which comprises forming a reactive Selected from the class consisting of hydrogen, fluoro, mixture of nitrophenylmethyldifluorosilane, silicon tetra chloro, bromo, iodo, cyano, chloride and tri-n-heptylamine, and heating said mixture to 55 a temperature between about -20° C. and about 200° C. -COO G, -NG, -O G, to cause redistribution of the silicon-fluorine and silicon -C-G, -C-NG chlorine bonds in said mixture. and nitro, G is a monovalent hydrocarbon group, R’ is 7. The process which comprises forming a reactive Selected from the class consisting of hydrogen, the vinyl mixture of phenylmethyldifiuorosilane, trimethylchloro group, and Y-R- groups, X is selected from the class 60 silane and tri-n-hexylamine, and heating said mixture to consisting of fluorine and chlorine, e is an integer having a temperature between about -20° C. and about 200° C. a value from 0 to 3, f is an integer having a value from to cause redistribution of the silicon-fluorine and silicon 0 to 1 and the sum of e and f is never greater than 3, (b) chlorine bonds in said mixture. linear polysiloxanes represented by the formula: 8. The process which comprises forming a reactive 65 mixture of phenylmethyldifluorosilane, silicon tetra bromide and phenyldiethylphosphine, and heating said mixture to a temperature between about -20° C. and about 200 C. to cause redistribution of the silicon wherein R, Y and X have the meanings defined herein fluorine and silicon-bromine bonds in said mixture. above and y is an integer having a value from 1 to 10,000, 70 9. A process for producing an organo-functional halo and (c) cyclic polysiloxanes represented by the formula: silane represented by the formula: x –Y (I) (Y-R-)SiO4. -si- O -Si-O wherein R is a divalent hydrocarbon group, Y is a group R-Y. R-Ys 75 Selected from the class consisting of hydrogen, fluoro, 3,128,297 25 26 chloro, bromo, iodo, cyano, normal valencies of the nitrogen atoms are bonded to O O carbon atoms of hydrocarbon moieties, tri(monovalent -COO G-, -NG-2, | -O G, hydrocarbon group) phosphines and silylamines repre -C-G, -C-NG2 sented by the formula: and nitro, G is a monovalent hydrocarbon group, Q is selected from the class consisting of chlorine, bromine and iodine, and i is an integer having a value from 1 to wherein G has the meaning defined hereinabove, and m 3 which process comprises (1) forming a reactive mix is an integer having the value of zero to 3, (2) heating ture of (a) a fluorosilane represented by the formula: said mixture to a temperature sufficiently elevated to cause redistribution of the silicon-fluorine and silicon (II) (Y-R-) SiFA O chlorine bonds in said compounds of Formulas II and wherein R, Y and i have the meanings defined herein III, (3) removing from said mixture a fluorosilane re above and wherein the functionality of the compound of presented by the formula: Formula II is the same as the functionality of the desired (IV) (Z-R) SiFA product of Formula I, (b) a halosilane represented by 5 the formula: wherein R, Z and i have the meanings defined herein above, and (4) thereafter recovering from the resulting (III) (Z-R-) SiQ4 reaction mixture the product of Formula I. wherein R, Q and i have the meanings defined herein 11. A continuous process for producing an organo above and Z is different from the Y group of the com functional chlorosilane represented by the formula: pound of Formula I and is selected from the class con 20 sisting of hydrogen, fluoro, chloro, bromo, iodo, cyano, (I) (Y-R-) SiCl4 O O wherein R is a divalent hydrocarbon group containing -COO G-, -NG, -O G, from 1 to 17 carbon atoms, Y is a group selected from -C-G, -C-NG the class consisting of hydrogen, fluoro, chloro, bromo, and nitro, and with (c) a basic catalyst selected from the 25 iodo, cyano, class consisting of tertiary amines wherein all three nor O O mal valencies of the nitrogen atoms are bonded to carbon -COO G-, -NG-2, atoms of hydrocarbon moieties, tri(monovalent hydrocar bon group) phosphines and silylamines represented by the and nitro, G is a monovalent hydrocarbon group con formula: 30 taining from 1 to 10 carbon atoms, and i is an integer having a valve from 1 to 3 which process comprises (1) wherein G has the meaning defined hereinabove, and converting by chemical reactions a fluorosilane repre m is an integer having the value of zero to 3, (2) heat sented by the formula: ing said mixture to a temperature sufficiently elevated to 35 (II) (Z-R-) SiF-1 cause redistribution of the silicon-fluorine and other sili con-halogen bonds in said compounds of Formulas Ii wherein R and i have the meanings defined hereinabove and Z is different from the Y group of the compound of and III, (3) removing from said mixture a fluorosilane Formula I and is selected from the class consisting of represented by the formula: hydrogen, fluoro, chloro, bromo, iodo, cyano, (IV) (Z-R-) (SiF 40 wherein R, Z and i have the meanings defined herein O above, and (4) thereafter recovering from the resulting -COO G-, -NG, reaction mixture the product of Formula I. 10. A process for producing an organo-functional and nitro and wherein the functionality of the compound 45 of Formula II is the same as the functionality of the chlorosilane represented by the formula: desired product of Formula I, to a fluorosilane repre (I) (Y-R-) SiCl4 sented by the formula: wherein R is a divalent hydrocarbon group, Y is a group (III) (Y-R-) SiFA selected from the class consisting of hydrogen, fluoro, 50 wherein R, Y and i have the meanings defined herein chloro, bromo, iodo, cyano, above, (2) forming a reactive mixture of (a) said fluoro O O -COO G-, -NG2, silane of Formula III, (b) a chlorosilane represented -C-G, by the formula: and nitro, G is a monovalent hydrocarbon group and i (IV) (Z-R-) SiCl4 is an integer having a value from 1 to 3 which process 55 wherein Z, R and i have the meanings defined herein comprises (1) forming a reactive mixture of (a) a fluoro above and wherein the functionality of the compound of silane represented by the formula: Formula IV is the same as the functionality of the de (II) (Y-R-) SiF sired product of Formula I, and (c) a basic catalyst selected from the class consisting of tertiary amines wherein R, Y and i have the meanings defined herein 60 wherein all three normal valencies of the nitrogen atoms above and wherein the functionality of the compound of are bonded to carbon atoms of hydrocarbon moieties, Formula II is the same as the functionality of the desired tri(monovalent hydrocarbon group) phosphines and product of Formula I, (b) a chlorosilane represented by silylamines represented by the formula: the formula: (III) (Z-R-)SiCl4 65 wherein G has the meaning defined hereinabove, and wherein R and i have the meanings defined hereinabove m is an integer having the value of zero to 3, (3) heat and Z is different from the Y group of the compound ing said mixture to a temperature between about -20 of Formula I and is selected from the class consisting of C. and about 200° C. to cause redistribution of the sili hydrogen, fluoro, chloro, bromo, iodo, cyano, 70 con-fluorine and silicon-chlorine bonds in said compounds O O of Formulas III and IV, (4) removing from said mixture -COO G-, -NG, a fluorosilane represented by the formula: and nitro, and with (c) a basic catalyst selected from (II) (Z-R-) (SiF the class consisting of tertiary amines wherein all three 75 wherein R, Z and i have the meanings defined herein 3,128,297 27 above, (5) thereafter recovering from the resulting reac the functionality of said halosilane of Formula I, which tion mixture the product of Formula I, and (6) recycl process comprises (1) adding to said halosilane mixture ing the fluorosilane removed in step (4) thereby provid (c) at least one source of fluorine selected from the ing the fluorosilane of Formula i required in step (1). group consisting of hydrogen fluoride, alkali metal fluoro 12. A continuous process for producing nitrophenyltri silicates, metal fluorides, and fluorosilanes having higher chlorosilane which comprises (1) converting by chemi boiling points than the halosilanes of said mixture and cal reaction phenyltriiiuorosilane to nitrophenyltrifluoro represented by the formula: silane, (2) forming a reactive mixture of nitrophenyltri fluorosilane, phenyltrichlorosilane and tri-n-butylamine, (III) R' (3) heating said mixture to a temperature between about 0 (Z-R-) SiF 4-t-u -20 C. and 200 C. to cause redistribution of the wherein R, t and u have the meanings defined herein silicon-chlorine and silicon-fluorine bonds in said mix above, Z is a group selected from the class consisting ture, (4) removing phenyltrifluorosilane from said mix of hydrogen, fluoro, chloro, bromo, iodo, ture, (5) thereafter recovering nitrophenyltrichlorosilane O O from the resulting reaction mixture, and (6) recycling the 5 -COO G-, -NG, -O G, phenyltrifluorosilane removed in step (4) for use in -C- G, -G-NG2 step (1). and nitro, G is a monovalent hydrocarbon group and 13. A continuous process for producing bis(nitro R’ is selected from the class consisting of hydrogen, phenyl) dichlorosilane which comprises (1) converting by the vinyl group and Z-R- groups, the quantity of said chemical reaction bis(phenyl) difluorosilane to bis(nitro 20 source of fluorine being such as to provide about one phenyl) difluorosilane, (2) forming a reactive mixture moie of available fluorine per mole of silicon-halogen of bis(nitrophenyl) difluorosilane, bis(phenyl) dichloro bonds in said halosilanes of Formula II, and (d) a silane and tri-n-hexylamine, (3) heating said mixture to catalyst selected from the class consisting of tertiary a temperature between about -20° C. and about 200° C. amines wherein all three normal valencies of the nitrogen to cause redistribution of the silicon-chlorine and silicon atoms are bonded to carbon atoms of hydrocarbon fluorine bonds in said mixture, (4) removing bis(phenyl) moieties, tri(monovalent hydrocarbon group) phosphines difluorosilane from said mixture, (5) thereafter recover and silylamines represented by the formula: ing bis(nitrophenyl) dichlorosilane from the resulting re action mixture and (6) recycling the bis(phenyl) difluoro silane removed in step (4) for use in step (1). 30 wherein G has the meaning defined hereinabove, and m 14. A continuous process for producing gamma-cyano is an integer having the value of zero to 3, (2) heating propylmethyldichlorosilane which comprises (1) convert the composite mixture to a temperature sufficiently ele ing by chemical reaction methyldifluorosilane to gamma wated to form silicon-fluorine bonds and to cause re cyanopropylmethylidifluorosilane, (2) forming a reactive distribution of the silicon-fluorine and other silicon-halo mixture of gamma-cyanopropylmethyldifluorosilane, 35 gen bonds of the compounds in said composite mixture, methyldichlorosilane and tri-n-butylamine, (3) heating (3) removing from said composite mixture relatively said mixture to a temperature between about -20° C. more volatile fluorosilanes represented by the formula: and about 200° C. to cause redistribution of silicon-chlo (IV) R". rine and silicon-fluorine bonds in said mixture, (4) re (Y-R-) SiF4-t-u moving methyldifluorosilane from said mixture, (5) 40 wherein R, R', Y, t and u have the meanings defined thereafter recovering gamma-cyanopropylmethyldichloro hereinabove, and (4) thereafter recovering from the re silane from the resulting mixture and (6) recycling the sulting reaction mixture the halosilane of Formula I. methylidifluorosilane removed in step (4) for use in 16. A process for the separation of a chlorosilane from step (1). a mixture thereof with other chlorosilanes having higher 15. A process for the separation of a halosilane from 45 functionality, said mixture consisting essentially of (a) a mixture thereof with other halosilanes having higher functionality, said mixture consisting essentially of (a) as the major component thereof a chlorosilane represented as the major component thereof a halosilane represented by the formula: by the formula: (I) B', (I) Rh 50 (Y-R-)SiCl4-g-h (Y-R-)-dio wherein R is a divalent hydrocarbon group, Y is a group wherein R is a divalent hydrocarbon group, Y is a group Selected from the class consisting of hydrogen, fluoro, selected from the class consisting of hydrogen, fluoro, chloro, bromo, iodo, cyano, O chloro, bromo, iodo, cyano, -COO G-, -NG, -O G, O O -COO G-, -NG, | -O G, -C-G, -C-NG2 and nitro, G is a monovalent hydrocarbon group, R' is selected from the class consisting of hydrogen, the vinyl and nitro, G is a monovalent hydrocarbon group, R is 60 group and Y-R-groups, g is an integer having a value selected from the class consisting of hydrogen, the vinyl from 1 to 3, h is an integer having a value from 0 to 1, group and Y-R- groups, Q is selected from the class and the sum of g and h is never greater than 3, and (b) consisting of chlorine, bromine and iodine, g is an integer as the minor component thereof at least one chlorosilane having a value from 1 to 3, h is an integer having a represented by the formula: value from 0 to 1, and the sum of g and h is never 65 greater than 3, and (b) as the minor component thereof (II) Ru at least one halosilane represented by the formula: (II) R'u wherein Y, R and R' have the meanings defined herein above, t is an integer having a value from 0 to 2, u is an integer having a value from 0 to 1 and the sum of t wherein Y, R, R and Q have the meanings defined and u is never greater than 2, and wherein the func hereinabove, t is an integer having a value from 0 to 2, tionality of said chlorosilanes of Formula II is higher u is an integer having a value from 0 to 1 and the sum than the functionality of said chlorosilane of Formula I, of t and u is never greater than 2, and wherein the func which process comprises (1) adding to said chlorosilane tionality of said halosilanes of Formula II is higher than 7 5 mixture (c) at least one source of fluorine selected from 3,128,297 29 30. the group consisting of hydrogen fluoride, alkali metal t and u is never greater than than 2, and wherein the fluorosilicates, metal fluorides, and fluorosilanes having functionality of said chlorosilanes of Formula II is higher than the functionality of said chlorosilane of Formula I higher boiling points than the chlorosilanes of said mix which process comprises (1) adding to said chlorosilane ture and represented by the formula: mixture (c) at least one fluorosilane having a higher (III) boiling point than the chlorosilanes in said mixture and (Z-R-) SiF-t-u represented by the formula: wherein R, t and u have the meanings defined herein (III) above, Z is a group selected from the class consisting of hydrogen, fluoro, chloro, bromo, iodo, (Z-R-) SiF4-t-u O wherein R, t and u have the meanings defined herein -COO G-, -NG, -O G, above, Z is a group selected from the class consisting of -C-G, hydrogen, fluoro, chloro, bromo, iodo, cyano, 5 and nitro, G is a monovalent hydrocarbon group and O O R’ is selected from the class consisting of hydrogen, the -NG-2, -O G, vinyl group and Z-R- groups, the quantity of Said -COO G-, -C-G, -C-NG source of fluorine being such as to provide about one mole of available fluorine per mole of silicon-chlorine and nitro, G has the meaning defined hereinabove and bonds in said chlorosilanes of Formula II, and (d) a 20 R' is selected from the class consisting of the vinyl catalyst selected from the class consisting of tertiary group and Z-R- groups, the quantity of said fluoro amines wherein all three normal valencies of the nitrogen silane being such as to provide about one mole of avail atoms are bonded to carbon atoms of hydrocarbon able fluorine per mole of silicon-chlorine bonds in said moieties, tri(monovalent hydrocarbon group) phosphines chlorosilanes of Formula II, and (d) a tertiary amine 25 catalyst, all three normal valencies of the nitrogen atoms and silylamines represented by the formula: in said amine being bonded to carbon atoms of hydro GmSi (NG) 4-m carbon moieties, (2) heating the composite mixture to a temperature between about -20° C. and about 200 wherein G has the meaning defined hereinabove, and m C. to cause redistribution of the silicon-fluorine and sili is an integer having the value of zero to 3, (2) heating 30 con-chlorine bonds of the compounds in said composite the composite mixture to a temperature sufficiently ele mixture, (3) removing from said composite mixture rela vated to form silicon-fuorine bonds and to cause re tively more volatile fluorosilanes represented by the distribution of the silicon-fluorine and silicon-chlorine formula: bonds of the compounds in said composite mixture, (3) removing from said composite mixture relatively more 35 (IV) Ru volatile fluorosilanes represented by the formula: wherein R, R', Y, t and u have the meanings defined here inabove, and (4) thereafter recovering from the result 40 ing reaction mixture the chlorosilane of Formula I. wherein R, R', Y, t and u have the meanings defined 18. A process for separating phenylmethyldichloro hereinabove, and (4) thereafter recovering from the re silane from a mixture consisting essentially of a major sulting reaction mixture the chlorosilane of Formula I. amount of phenylmethyldichlorosilane and a minor 17. A process for the separation of chlorosilanes from amount of phenyltrichlorosilane which comprises (1) a mixture thereof with other chlorosilanes having higher 45 adding to said mixture sodium fluorosilicate in an amount functionality, said mixture consisting essentially of (a) sufficient to provide at least about one mole of fluorine as the major component thereof a chlorosilane repre per mole of silicon-chlorine bonds in said phenyltrichloro sented by the formula: silane and N,N-diethylaniline catalyst, (2) heating the composite mixture to a temperature between about -20 () Rh 50 C. and about 200 C. to form silicon-fluorine bonds and to (Y-R-)SiCl4-g-h cause redistribution of the silicon-fluorine and silicon chlorine bonds in said composite mixture, (3) removing wherein R is a divalent hydrocarbon group containing phenyltrifluorosilane from said mixture and (4) there from 1 to 17 carbon atoms, Y is a group selected from after recovering phenylmethyldichlorosilane from the re the class consisting of hydrogen, fluoro, chloro, bromo, 55 Sulting reaction mixture. iodo, cyano, 19. A process for separating dimethyldichlorosilane from a mixture consisting essentially of a major amount O O of dimethyldichlorosilane and a minor amount of methyl -COO G, -NG 2, G -O G, l NG -u-u, - - 2 trichlorosilane which comprises (1) adding to said mix 60 ture phenyltrifluorosilane in an amount sufficient to pro and nitro, G is a monovalent hydrocarbon group con vide at least about one mole of silicon-fluorine bonds per taining from 1 to 10 carbon atoms, R is selected from mole of silicon-chlorine bonds in said methyltrichloro the class consisting of hydrogen, the vinyl group and silane and N,N-diethylaniline catalyst, (2) heating the Y-R- groups, g is an integer having a value from 1 composite mixture to a temperature between about -20° to 3, h is an integer having a value from 0 to 1, and 65 C. and about 200 C. to cause redistribution of the sili the sum of g and u is never greater than 3, and (b) as con-fluorine and silicon-chlorine bonds in said composite the minor component thereof at least one chlorosilane mixture, (3) removing methyltrifluorosilane from said represented by the formula: mixture, and (4) thereafter recovering dimethyldichloro silane from the resulting reaction mixture. (II) 70 20. A process for separating diphenyldichlorosilane from a mixture consisting essentially of a major amount (Y-R-) SiC.-- of diphenyldichlorosilane and a minor amount of bis wherein Y, R, and R' have the meanings defined herein (trichlorosilyl)benzene which comprises (1) adding to above, t is an integer having a value from 0 to 2, u is said mixture sodium fluorosilicate in an amount sufficient an integer having a value from 0 to 1 and the sum of 75 to provide at least about one mole of fluorine per mole 3,128,297 3. 32 of silicon-chlorine bonds in said bis(trichlorosilyl)ben- References Cited in the file of this patent Zene and tri-n-heptylamine catalyst, (2) heating the com- UNITED STATES PATENTS posite mixture to a temperature between about -20° C. and about 200° C. to form silicon-fluorine bonds and to 2,395,826 Hill et al. - m - - - - -a as aa - - - - - Mar. 5, 1946 cause redistribution of the silicon-fluorine and silicon- 5 2-39-81 Newkirk ------Sept. 21, 1948 chlorine bonds in said composite mixture, (3) removing 3,020,302 Bailey et al. ------Feb. 6, 1962 bis(trifluorosilyl)benzene from said mixture, and (4) FOREIGN PATENTS thereafter recovering diphenyldichlorosilane from the re- 761,205 Great Britain ------Nov. 14, 1956 Sulting reaction mixture.