3,398,171 United States Patent Office Patented Aug. 20, 1968 2 3,398,171 In connection with the foregoing publication of Hurd, PROCESS OF PRODUCING ORGANOHALOSILANES it is appropriate to point out that at least as late as 1956, Albert P. Giraitis, Paul Kobetz, and Francis M. Beaird, eight years subsequent to 1948, the direct process was still Jr., Baton Rouge, La., assignors to Ethyl Corporation, the mainstay of the industry as evidenced by Charles E. New York, N.Y., a corporation of Virginia 5 Reed, Edgar Marburg Lecture 1956, American Society No Drawing. Filed Mar. 2, 1964, Ser. No. 348,824 for Testing Materials publication, “The Industrial Chemis 41 Claims. (C. 260-448.2) try, Properties, and Applications of Silicones,” pp. 16-18. It is believed that this situation of preminence of the direct process prevails in the industry ot this day, despite ABSTRACT OF THE DISCLOSURE its shortcomings. The selective preparation of particular organo-halo O The yields of the typical prior art processes for the silicon compounds at low temperatures of about -10 to commercial production of diorganodihalosilanes are un 50 C. in certain stoichiometric relationships of reactants desirably low and result in the production of excessive is described. A new stepwise substitution of halogens by quantities of monohalo or monoorgano compounds. organo groups is obtained. The low temperatures are U.S. Patent 2,859,229 is directed to the alkylation of retained through recovery operations. lead chloride with mixed metal alkyls in which the only product is tetraalkyllead, there being no haloalkyllead combinations in the products. Additionally, it is to be ob This invention relates in general to the preparation of served that this typical prior art alkylation process results intermediates for organo-silicon products. In greater par in the production of elemental lead and that the overall ticularity, it relates to the production of organo-halosilanes 20 conversion to the tetraalkyllead compound is of the order Such as dimethyldichlorosilane. of 50% of the lead employed. In other words, two mole There are several known prior art processes whereby cules of lead chloride are employed to produce one mole materials such as the foregoing can be produced. At the cule of tetraethyllead. It must be observed, however, that present time, however, the process of principal commer that process does not represent a loss of the lead involved cial interest is the so-called direct process by means of since it is possible to utilize the lead for other purposes which organo-halosilanes are produced by the direct re since it has special properties because of its high activity. action of methyl chloride with silicon metal in the pres The fact remains that that process which is considered ence of a copper catalyst. This process is described for typical of the mixed metal alkylation process as heretofore example in "Organic Silicon Compounds," C. Eaborn, known has entirely different characteristics and purposes Academic Press, Inc., 1960, page 36. As is well known 30 and does not result in the production of any material and readily apparent from the foregoing reference ma of the type now envisioned or desired. terial, this direct process does not produce solely the de A further example of the state of the art is German sired dialkyl-dihalosilane but rather produces a number Patent 1,158,976 which shows that attempts are still being of other silane combinations such as organothiohalosilane, made to improve the direct process. It is noteworthy that triorganohalosilane, and tetraorganosilane. It is important the improvement obtained by that patent is of litle signifi to observe that this particular process is conducted at ele cance in comparison to that of the present invention. vated temperatures such as 300-400° C. As a practical It is accordingly an object of the present invention to matter the conversion efficiency of this direct process in provide an improved process by which organotrihalo, di terms of material converted to the desired diorganodihalo 40 organodihalo, or triorganohalo compounds may be pro silane is limited to approximately 65% with the balance duced selectively at high efficiency. being made up of approximately 15% organotrihalosilane, Another object of the present invention is to provide a 5% triorganohalosilane, and 15% represented by higher process for the production of diorganodihalosilanes with and lower boiling materials. In conducting the direct re high efficiency from comparatively low priced raw ma action, combination in various stoichiometric proportions terials. occurs as indicated by Eaborn at page 37. However, it is 45 Another object of the present invention is to produce not possible to achieve control of the combination ratios dimethyldichlorosilane at high efficiency. or selectivity of the displacement of the halogen from any Other and further objects and features of the present particular member of the organohalosilanes so that as a invention will become apparent upon careful considera practical matter the foregoing 65:15:5 ratio is virtually a tion of the following detailed description. statistical matter which cannot be varied by any previous 50 In accordance with the basic teachings of the present ly known technique. invention, selective production of organohalosilanes at Another prior art process for the preparation of organo high efficiency is accomplished by the reaction of a sili halosilanes is the Grignard reaction in which an alkyl con tetrahalide under precisely controlled reaction con magnesium halide is combined with silicon tetrahalide in 55 ditions using particular bimetallic compounds AMR ether solution to produce dialkyldihalosilane together with as hereafter defined. As an adjunct to the basic teachings other silanes, the yield of the desired material being of of this invention a recovery process is provided whereby the order of 55%. As with the direct process, the con the desired silanes are obtained without degradation version by the Grignard process is also a statistical mat thereof. ter and there is virtually no possibility of improving the More specifically the present invention provides a proc production ratio for the desired material. 60 ess for the production of organohalosilanes in which a A further example of the prior art existing in this field mixed metal compound AMR having one metal (A) is the article by D. T. Hurd in the Journal of Organic which is an alkali metal of atomic number 3-19, both Chemistry, 13, 711-13 (1948) relating to the preparation limits inclusive, the other metal (M) selected from the of complex metal alkyls. In that article the reaction of group consisting of aluminum, boron, and zinc and con LiAl(CH3)4 with silicon tetrachloride was described as 65 taining an organic radical desired for the product is methylation. added to a halosilane having at least 2 halogen atoms As will be brought out in the discussion that follows, bonded to the silicon atom while maintaining the reac mere methylation, broadly described, is not the important tion temperature from about -20° C. to about --50° C., aspect of the present invention. The importance of the the amount of said compound AMR being 1 mol per present invention lies in the teachings as to how con 70 mol equivalent of halogen being displaced from the sili trollable selective reaction can be attained and retained. COn aton. 3,398,171 3 4. It is not generally recognized that recovery can be The characteristic of these foregoing conversions is that an important phase of the production of organohalosil they are irreversible when performed under the conditions anes. In the present process, however, some of the or employed so that once material of a higher order of ganohalosilanes will react further below usual distilla organo content is formed it is not possible to drive in tion temperatures. Thus a significant part of the present the opposite direction. Thus it is essential that care be invention is that, for certain materials, recovery is criti observed in the addition of compound AMR and that cal and must be performed with careful control of con localized excesses of compound AMR be avoided ditions to avoid destroying the selectivity attainable in through the use of adequate agitation. the basic reaction. The basic reaction in accordance with the present in Yields of desired diorganodihalosilanes of the order of 0. vention is represented by the following: 95% or better are readily obtained using the teachings To of the present invention. Virtually complete selectivity Six -- 2AMR --- R2Six2 -- 2AX -- 2MR3 as to the mol ratio of the organic components to the Solwent halogen components has been obtained. Thus it is pos wherein the compound AMR is defined as follows: sible to produce the desired diorganodihalosilane or any 5 A is sodium, potassium, or lithium. of the others starting from the silicon tetrahalide or a M is aluminum, boron, or zinc. compound having a lesser ratio of halide to organo than Rn is selected from the group consisting of alkyl, aryl, the tetrahalide but which ratio is greater than that of the alkoxy, aryloxy, halo, hydrogen or combinations. The desired product. value of n depends upon the A and M employed typi It has been observed that the principal conventional 20 cally being 4 for Na and Al. One R of R must be prior art processes for diorgano-dihalosilane production an alkyl or aryl, the others can be the same alkyl or identified in the foregoing as the direct process and the aryl or different, as well as various combinations of Grignard process produce significant quantities of by the members of the same or different categories. product organotrihalosilane. By utilizing the teachings The halide component X of the materials can be any of the present invention it is possible to convert this or halide, typically chlorine or fluorine. In view of the ganotrihalosilane into the desired diorganodihalosilane breadth of the basic invention as set forth, however, it at virtually 100% efficiency of conversion without pro is to be understood that the X is defined as being broad ducing any substantial quantity of the triorganohalosil enough to include all halogens as well as hydrogen and ane or tetraorganosilane. combinations including halogens and organics. The speci It is thus seen that the teachings of the present in 30 fication of the X at this point is thus made sufficiently vention have utility as a new process for the production broad to include the application of the basic selective of the desired diorganodihalosilanes at high yield of the reaction to a "clean up' of the by-product RSiCl3 pro order of or better than 95% or can be used to improve duced by the prior are direct process and Gringnard reac the prior art processes and the facilities utilizing them. tion by means of which the organotrihalosilane is con As has been mentioned, one of the principal factors in verted to the diorganodihalosilane. the successful performance of the present invention is The following silicon compounds are useful for Six: control of temperature during reaction as well as sub silicon tetrachloride, silicon tetrafluoride, silicon tetrabro sequent thereto. The prior art direct process character mide, silicon tetraiodide or combinations thereof such as ized by the elevated operational temperatures such as dichlorodifluorosilicon, bromotrichlorosilicon, together several hundred degrees centigrade involves such high 40 with materials such as methyltrichloro silane, ethyltri reactivity of the halogen in all involved silane forms that chlorosilane, methyltrifluorosilane, ethyltrifluorosilane, it is impossible to avoid reacting to complete substitu phenyltrichlorosilane, benzyltrichlorosilane, methoxytri tion of halogen by the organo radical as for example in chlorosilane, ethoxytrichlorosilane, isopropoxytrichloro the production of tetraethylead or tetramethylsilicon. silane, and diacetodichlorosilane, When the present reaction is conducted in solution un Similar compounds of germanium, tin, antimony and der controlled conditions, however, it is possible to bismuth may be substituted for the typical silicon com achieve a reaction at lower temperatures, typically be pounds. low the 100° of the Grignard type of reaction to obtain Typical compounds AMR are: lithium aluminum tetra controllied relative reactivity. Even under the operating methyl, lithium aluminum tetraethyl, lithium methoxytri conditions employed in the Grignard reaction, there is 50 methylaluminum, lithium ethoxytrimethylaluminum, lithi complete absence of selectivity as to the displacement um t-butoxytrimethylaluminum, lithium dimethyldi-t- of halogen atoms so that a statistical distribution of butoxyaluminum, lithium diethyldiethoxyaluminum, lithi products occurs. It has now been discovered that at um aluminum tetraphenyl, lithium aluminum trimethyl substantially lower reaction temperatures than those phenyl, lithium dimethylaluminumdiphenyl, lithium, alumi conventionally used for the production of organo-silanes num isopropoxymethyl, lithium aluminum triethoxymeth it is possible to achieve selectivity when the reaction is yl, lithium aluminum trichlorophenyl. performed in an appropriate solvent media, with the re Other compounds AMR are: sodium aluminum tetra actants combined in specific ratios and in the proper methyl, sodium aluminum tetraethyl, sodium methoxytri order. Although some materials will react in solid form methylaluminum, sodium ethoxytrimethylaluminum, sodi and others will provide inherent solvent nature, many 60 um t-butoxytrimethylaluminum, sodium dimethyldi-t- reactions are improved substantially in the solvent media butoxyaluminum, sodium diethyldiethoxyaluminum, sodi mentioned. um aluminum tetraphenyl, sodium aluminum trimethyl The process of the present invention thus involves phenyl, sodium dimethylaluminumdiphenyl, sodium alumi radical departure from the prior art in contemplating num isopropoxymethyl, sodium aluminum triethoxymeth that under appropriate conditions where a compound yl, sodium aluminum trichlorophenyl. AMR, as hereafter defined is added to a silicon tetra Other typical compounds AMR are: sodium boron halide, progressive complete conversion to the organo tetramethyl, sodium boron tetraethyl, sodium boron meth trihalosilane will first occur, that with additional com oxytrimethyl, sodium boron ethoxytrimethyl, sodium bo pound AMR this material will in turn be progressively ron t-butoxytrimethyl, sodium boron dimethyldi-t-butoxy, and completely converted into the diorganodihalosilane, sodium boron diethyldiethoxy, sodium boron tetraphenyl, that with additional compound AMR, progressive and sodium boron trimethylphenyl, sodium boron dimethyldi. complete conversion of the diorganodihalosilane into the phenyl, sodium boron isopropoxymethyl, sodium boron triorganohalosilane occurs, and that with additional com triethoxymethyl, sodium boron trichlorophenyl. pound AMR progressive and complete conversion of Other typical reactants AMR are: potassium aluminun the triorganohalosilane into the tetraorgano form occurs. 75 tetramethyl, potassium aluminum tetraethyl, potassium 3,398,171 5 6 methoxytrimethylaluminum, potassium ethoxytrimethyl the first level to completion at the second level. For com aluminum, potassium t-butoxytrimethylaluminum, potas plete conversion to the diorganodihalo, a two unit reduc sium dimethyldi-t-butoxyaluminum, potassium diethyldi tion from Six, two moles of the compound AMR are ethoxyaluminum, potassium aluminum tetraphenyl, potas required per mole of silicon tetrachloride. sium aluminum trimethylphenyl, potassium dimethyl Since the reactions are irreversible, inadequacy of mix aluminumdiphenyl, potassium aluminum isopropoxymeth ing may result in localized excesses of compound AMR yl, potassium aluminum triethoxymethyl, potassium in the reaction mass. This causes the production of some aluminum trichlorophenyl. material of a higher degree of substitution than desired Other typical reactants AMR are: sodium trimethyl which cannot be reconverted to the desired lower level of zinc, sodium triethylzinc, sodium triphenylzinc, lithium O substitution except through some other conversion scheme. trimethylzinc, lithium triethylzinc, lithium triphenyl zinc, To minimize this condition it may be desirable in some potassium trimethylzinc, potassium triethylzinc, potassium instances to employ a slight deficiency of compound triphenylzinc. AMR relative to that required for complete conversion Other typical reactants AMR are: lithium aluminum to any particular level of substitution, thereby deliber trimethylhydride, lithium aluminum triisopropoxyhydride, 5 ately producing incomplete conversion to the level de lithium aluminum trichlorohydride, sodium aluminum tri sired, and to separate the material incompletely converted methylhydride, sodium aluminum triisopropoxyhydride, for subsequent recycle. sodium aluminum trichlorohydride, potassium aluminum The foregoing reaction is preferably performed in a trimethylhydride, potassium aluminum triisopropoxyhy solvent medium. The particular solvents employed have dride, potassium aluminum trichlorohydride, sodium tri 20 substantial effect upon the reaction, the rates, and the methylborane, potassium triisopropoxyborane, sodium tri yield, as well as the optimum reaction temperature and chloroborane. the recovery of the product. However, in general the sol The mixed metal salts react readily with silicon halide vents are selected from materials which are solvents for or silicon alkoxide bonds to replace halogen attached to the compound AMR although not necessarily solvents the silicon in the molar proportion of the complex salt 25 for other materials that might be present. reactant. Thus several broad classes of solvents may be set forth, In the basic material AMR if the R's are different the first being ethers such as diethylether, tetrahydrofuran such as AMRR2 and the various polyalkyl ethers of the ethylene glycols where . such as the dimethylether of diethyleneglycol, the dimeth R=alkyl or aryl 30 ylether of ethyleneglycol, the diethylether of diethylene R’ is equal to alkyl or aryl but different from R, glycol, the methylethylether of diethyleneglycol, the ben there is satistical chance for either group to attach to the zylethylether of diethyleneglycol, and various ethers of silicon in substitution of the X. For example, triethyleneglycol and higher order materials. The second broad class of solvents is identified as hy 2 NaAl(CH3)2(CH3)2 -- SiCl4 -> (CH3) (C2H5) Cl2Si 35 drocarbons; aromatics, such as toluene and benzene; ali phatics, such as octane, decane, and tetradecane; and un saturates, such as tetradecene, hexadecene, and octene. A third general category of solvents includes mixtures of hydrocarbons and ethers which would in general be 40 desired to permit use of hydrocarbon solvents which are not themselves solvents for the compound AMR but which can be used with sufficient ether to complex with the compound AMR to produce solution. Typically such complexing would involve a 1:1 mole ratio of ether to 45 the compound AMRn. The fourth general category of solvents suitable for conducting the reaction includes the amines such as pyr idine, and N,N-dimethyl aniline. The reactants set forth in the foregoing are required to be added in a specific manner; namely, the compound 50 EXAMPLE I AMR is added to the Six progressively and with ade quate agitation, to avoid the existence of excess com Preparation of (CH3)2SiCl, from MeClSi pound AMR in localized regions of the reactor. 2 parts of NaAl(CH3)4 was dissolved in 20 parts di The temperature of the reaction is specified broadly as methyl carbitol and added dropwise with stirring to a solu being from about -20° to about --50 C., preferably 55 tion of 3 parts of MeSiCl3 in 5 parts of dimethyl carbitol from about 0° to about -20° C. and typically about at 50 C. During this addition, insoluble NaCl precipi 10° C. The basic requirement is that the temperature tated. be such as to "spread' the reactivity of the halogen in The resulting material was distilled below 50 under the various substituted silane compounds to achieve selec vacuum, to recover silicon compounds as overhead. tive reactivity of the X in the higher order X-compounds 60 The analysis by VPC of the overhead showed 85% over that in the lower order X-compounds despite the fact dimethyldichlorosilane, 10% trimethylchlorosilane, 5% that a 90% efficiency envisions the fact that the lower methyltrichlorosilane. order substituted X-silane will be present in a typical 9:1 ratio relative to the higher order X-silane. EXAMPLE II The selectivity of production of organohalosilanes in accordance with the present invention is affected to a Preparation of (CH3) (C2H5)SiCl2 from MeClSi profound extent by the proportion of the reactants em 12.72 parts of NaAl(CH5)4 (90% of theory) was dis ployed. Thus in adding the compound AMRn to the solved in 75 parts dimethyl Carbitol. This solution was silicon halide, attention must be given to the correct added dropwise with stirring to a solution of 12.7 parts of proportions depending upon the unit value reduction of 70 methyltrichlorosilane in 10 parts of dimethyl Carbitol at X between the reactant Six and the desired product. The 25 C. During the addition insoluble sodium chloride pre mole ratio of the reactants is precisely 1:1 per substituted cipitated. The resulting material was distilled and a cut X. Thus the conversion of tetrahalosilane to trihalo is a taken from 70-100° C. The analysis by mass spectrometer unit reduction and requires one mole of compound AMRn showed 94% methylethyldichlorosilane, 4% methyl per mole of silicon tetrahalide to carry the reaction from 75 trichlorosilane, 2% dimethyl Carbitol. 3,398,171 7 8 EXAMPLE I and X indicates that further reaction occurred during Preparation of diethyldichlorosilane distillation at the higher pressure of Example X. 29 parts of NaAl(CH5) was dissolved in 100 parts of EXAMPLE X dimethyl Carbitol. This solution was added slowly with Preparation of dimethyldichlorosilane stirring to 14.8 grams of silicon tetrachloride at -10° C. 73.5 parts of sodium aluminum tetramethyl in 350 parts During the addition insoluble sodium chloride precipi of dimethyl Carbitol was added to 56.6 parts of silicon tated. This was stirred for an additional hour. A cut was tetrachloride slowly at 23° C. with stirring for one hour. taken at 130-140° C. Analysis of the solution showed Sodium chloride precipitated. by mass spectrometer 60.5% diethyldichlorosilane, 2.1% O Part of the resulting mixture was distilled at 8 mm. of triethylchlorosilane, and 37.3% dimethyl Carbitol. mercury pressure, reading a final bottom temperature of EXAMPLE IV 60° C. The product contained 94% dimethyldichloro Preparation of dimethyldidecylsilane silane, 2% methyltrichlorosilane, and 4% trimethylchloro silane. 32 parts of sodium aluminum tetradecyl was added to 5 3.2 parts of dimethyldichlorosilane in 90 parts toluene EXAMPLE XII slowly and stirred one hour at 10° C. During the reac Part of the resulting mixture prepared in the reaction tion sodium chloride precipitated. Toluene was removed of Example XI was distilled at 760 mm. of mercury pres by distillation below 50° C. under vacuum. Viscous oil sure, reading a final bottom temperature of 167 C. was obtained. Analysis showed it to be 85% dimethyl The product contained 44% dimethyldichlorosilane, 50% didecylsilane. trimethylchlorosilane and 6% tetramethylsilane. EXAMPLE V EXAMPLE X Preparation of dimethyldichlorosilane Preparation of dimethyldichlorosilane 14.2 parts sodium aluminum triisopropoxymethyl was 25 A resulting reaction mixture was prepared as in Ex added to 5 parts of silicon tetrachloride in 50 parts di ample XI except the reaction temperature was 60 C. methyl Carbitoi slowly and stirred one hour at 25° C. So Part of the resulting reaction mixture was distilled at dium chloride precipitated. Dimethyldichlorosilane was 20 mm. of mercury pressure, reading a final bottoms recovered by distillation. temperature of 80° C. The product contained 73% di 30 methyldichlorosilane, 26% trimethylchlorosilane and 1% EXAMPLE VI. tetramethylsilane. Preparation of diethyldichlorosilane 8.8 parts sodium tetraethyl boron is added to 5 parts EXAMPLE XIV of silicon tetrachloride in 50 parts dimethyl Carbitol Part of the resulting reaction mixture of Example slowly and stirred one hour at 15° C. Sodium chloride 35 XIII was distilled at 760 mm. of mercury pressure, reach precipitates. Diethyldichlorosilane is recovered by distilla ing a final bottoms temperature of 168 C. The product tion below 50° C. at reduced pressure. contained 24% dimethyldichlorosilane, 63% trimethyl EXAMPLE VII chlorosilane and 13% tetramethylsilane. Comparison of results of Example XIII indicates further reaction oc Preparation of diethyldichlorosilane 40 curred during distillation. 10.3 parts sodium triethylzinc is added to 5 parts of silicon tetrachloride in 100 parts toluene slowly and EXAMPLE XV stirred one hour at 15 C. Sodium chloride precipitates. Preparation of trimethylchlorosilane Diethyldichlorosilane is recovered by distillation below Part of the resulting reaction mixture of Example XIII 50 at reduced pressure. 45 was flash distilled at 760 mm. of mercury pressure to a EXAMPLE VIII final temperature of 163 C. The product contained 96% trimethylchlorosilane and 3% tetramethyl. Results con Preparation of diphenyldichlorosilane pared with Example XIV indicate complete conversion of 20.6 parts sodium boron tetraphenyl is added to 5 parts dimethyldichlorosilane to trimethylchlorosilane, but wir of silicon tetrachloride in 50 parts dimethyl Carbitol tual absence of conversion to tetramethylsilane due to the slowly and stirred for one hour at 25 C. Sodium chloride short duration of time at the elevated distillation tem precipitates. Diphenyldichlorosilane is recovered by distil perature. lation below 50° at reduced pressure. Similar desirable results are obtained with other ma terials of the classes set forth when reacting and recover EXAMPLE IX 5 5 ing under the specified conditions of proportion, solvent, Preparation of dimethyldichlorosilane and temperature. 108 parts of sodium aluminum tetramethyl in dimethyl From the foregoing it is obvious that considerable Carbitol was prepared in situ by slowly adding 94 parts variation is possible in the practice of the invention with of trimethylaluminum to 25 parts of sodium (slight ex 60 out exceeding the scope thereof as defined in the ap cess) in 500 parts dimethyl carbitol at a temperature of pended claims. about 100-110 C. with vigorous stirring during 1 hour. What is claimed is: This mixture without purification was added to 81.5 1. The process for the selective production of organo grams of silicon tetrachloride slowly at 22° C. with stir halosilanes which includes ring for one hour. Sodium chloride precipitated. adding a compound having the formula: Part of the mixture was distilled at 8 mm. of mercury AMR pressure. The product contained 69% dimethyldichloro wherein, silane and 31% trimethylchlorosilane. A is an alkali metal having an atomic number of from 3 to 19, both inclusive, EXAMPLE X M is selecetd from the group consisting of alumi A part of the mixture prepared in the reaction of Ex num, boron and zinc, ample DX was distilled at 760 mm. of mercury pressure R is individually selected from the group con (1 atmosphere). The product contained 14% tetramethyl sisting of hydrocarbyl radicals, hydrocarbyloxy silane, 86% trimethylchlorosilane and 0.3% dimethyl radicals, halogen atoms and the hydrogen atom, dichlorosilane. Comparison of the results of Examples IX at least one R being selected from the class of 3,398,171 9. 10 radicals consisting of alkyl, aralkyl, aryl, and 18. The process of claim 2 wherein M is aluminum alkaryl, - and n is 4, and A is potassium. n is an integer exceeding the valence of M by one, 19. The process of claim 2 wherein M is zinc and in to a halo silane having at least two halogen atoms is 3. bonded to the silicon atom, 5 20. The process of claim 2 wherein A is potassium, M while maintaining the reaction temperature from about is aluminum, n is 4, X is chlorine, a is 0 and b is 4. -20 to about --50° C., 21. The process of claim 2 wherein A is potassium, the amount of said compound AMR added being 1 M is aluminum, n is 4, X is chlorine, a is 1 and b is 3. mol per each mol equivalent of halogen being dis 22. The process of claim 2 wherein A is sodium, M is placed from said silicon atom. O boron, n is 4, X is chlorine, a is 0 and b is 4. 2. The process for the selective production of organo 23. The process of claim 2 wherein A is sodium, M is halosilanes which comprises: boron, n is 4, X is chlorine, a is 1 and b is 3. incrementally adding a compound having the formula: 24. The process of claim 2 wherein A is sodium, M is AMR boron, n is 4, X is fluorine, a is 0 and b is 4. wherein, 15 25. The process of claim 2 wherein A is sodium, M A is an alkali metal having an atomic number of is boron, n is 4, X is fluorine, a is 1 and b is 3. from 3 to 19, both inclusive, 26. The process of claim 2 wherein A is sodium, M M is selected from the group consisting of alumi is zinc and n is 3, a is 0 and b is 4. inum, boron and zinc, 27. The process of claim 2 wherein A is sodium, M is R is individually selected from the group consist 20 zinc and n is 3, a is 1 and b is 3. of hydrocarbyl radicals, hydrocarbyloxy radi 28. The process of claim 2 further characterized in cals, halogen atoms and the hydrogen atom, at that the reaction is conducted in a liquid medium and re least one R being selected from the class of radi covery of the product is performed at a temperature which cals consisting of alkyl, aralkyl, aryl, and alk does not exceed the reaction temperature. aryl, 25 29. In the recovery of an organohalosilane the proc ess of distillation at a temperature from about -20 to n is an integer exceeding the valence of M by one, about --50° C. to a halosilane having the formula: 30. In the recovery of an organohalosilane the process Ra'SiX of distillation at a temperature from about 0 to -20° C. wherein, 30 31. In the recovery of an organohaiosilane the process each R is individually selected from the group of distillation from a solvent at a temperature of -20 to consisting of hydrocarbyl radicals, hydrocarbyl --50° C. oxy radicals and the hydrogen atom, 32. In the recovery of an organohalosilane the process X is a halogen atom, of distillation from a solvent at a temperature of 0 to a is 0, 1, or 2, 35 --20 C. b is an integer of from 2-4, the total of a--b be 33. The process for the selective production of organo ing 4, halosilanes which comprises: while maintaining the reaction temperature from incrementally adding a compound having the formula: about -20° to about --50 C, the amount of said compound so added being one mole 40 NaAlR thereof per mole of said halosilane for each unit wherein, reduction in the value of “b,” said amount being R is individually selected from the group consist insufficient to replace all of the halogen atoms in ing of hydrocarbyl radicals, hydrocarbyloxy Said halosilane. radicals, halogen atoms and the hydrogen atom, 3. The process of claim 2 wherein A is sodium. 45 at least one R being selected from the class of 4. The process of claim 2 wherein M is aluminum radicals consisting of alkyl, aralkyl, aryl, and and n is 4. alkaryl, 5. The process of claim 2 wherein A is sodium, M is to a halosilane having the formula: aluminum and n is 4. 6. The process of claim 2 wherein a is 0 and b is 4. 50 SiCl4 7. The process of claim 2 wherein a is 1 and b is 3. 8. The process of claim 2 wherein the temperature is while maintaining the reaction temperature from from about 0° to about --20° C. about -20 to about --50° C., 9. The process of claim 2 further characterized in that the amount of said compound so added being one mole the reaction is conducted in an inert liquid reaction 55 thereof per mole of said halosilane for each unit medium. reduction in the number of atoms of chlorine per 10. The process of claim 2 further characterized in that mole of silicon, the reaction is conducted in a solvent for said compound. said amount being insufficient to replace all of the 11. The process of claim 2 further characterized in that chlorine atoms in said halosilane. the reaction is conducted in a solvent for said compound 34. The process for the selective production of organo Selected from the group consisting of cyclic ethers, poly halosilanes which comprises: ethers, hydrocarbons, mixtures of said ethers and hydro incrementally adding a compound having the formula: carbons, and amines. NaAlR 12. The process of claim 2 further characterized in wherein, that the reaction is conducted in tetrahydrofuran. 65 R is individually selected from the group con 13. The process of claim 2 further characterized in sisting of hydrocarbyl radicals, hydrocarbyloxy that the reaction is conducted in the dimethylether of di radicals, halogen atoms and the hydrogen atom, ethylene glycol. at least one R being selected from the class of 14. The process of claim 2 further characterized in radicals consisting of alkyl, aralkyl, aryl, and that the reaction is conducted in the diethylether of di 70 ethylene glycol. alkaryl, 15. The process of claim 2 wherein A is potassium. to a halosilane having the formula: 16. The process of claim 2 wherein A is lithium. R'SiCl 17. The process of claim 2 wherein M is boron and in wherein, is 4. each R" is individually selected from the group 3,398,171 1. 12 consisting of hydrocarbyl radicals, hydrocarbyl said reaction being conducted in tetrahydrofuran and oxy radicals and the hydrogen atom. recovery of the product being performed at a tem while maintaining the reaction temperature from perature from about -20 C. to about --50 C. about -20° C. to about --50 C., 38. The process for the selective production of organo the amount of said compound so added being one mole 5 halosilanes which comprises: thereof per mole of said halosilane for each unit incrementally adding a compound having the formula: reduction in the number of atoms of chlorine per mole of silicon, NaAl(CH3)4 said amount being insufficient to replace all of the to a halosilane having the formula: chlorine atoms in said halosilane. 35. The process for the selective production of organo 10 CHSiCl3 halosilanes which comprises: while maintaining the reaction temperature from incrementally adding a compound having the formula: about 0 to about 20° C., the amount of said compound so added being one mole NaAIR 5 thereof per mole of said halosilane for each unit wherein, reduction in the number of atoms of chlorine per R is individually selected from the group consist mole of silicon, ing of hydrocarby radicals, hydrocarbyloxy said amount being insufficient to replace all of the radicals, halogen atoms and the hydrogen atom, chlorine atoms in said halosilane, at least one R being selected from the class of 20 said reaction being conducted in tetrahydrofuran and radicals consisting of alkyl, aralkyl, aryl, and recovery of the product being performed at a tem alkaryl, perature from about -20° C. to about --50° C. to a halosilane having the formula: 39. The process for the selective production of organo halosilanes which comprises: SiF incrementally adding a compound having the formula: while maintaining the reaction temperature from 25 about -20° to about --50 C., NaAl(CH3)4 the amount of said compound so added being one mole to a halosilane having the formula: thereof per mole of said halosilane for each unit re duction in the number of atoms of fluorine per mole 30 SiF of silicon, said amount being insufficient to replace all of the while maintaining the reaction temperature from fluorine atoms in said halosilane. about 0° to about 20 C., 36. The process for the selective production of organo the amount of said compound so added being one mole halosilanes which comprises: thereof per mole of said halosilane for each unit re incrementally adding a compound having the formula: duction in the number of atoms of fluorine per mole of silicon, NaAR said amount being insufficient to replace all of the wherein, fluorine atoms in said halosilane, R is individually selected from the group consist said reaction being conducted in tetrahydrofuran and ing of hydrocarbyl radicals, hydrocarbyloxy 40 recovery of the product being performed at a tem radicals, halogen atoms and the hydrogen atom, perature from about -20° C. to about --50 C. at least one R being selected from the class of 40. The process for the selective production of organo radicals consisting of alkyl, aralkyl, aryl, and halosilanes which comprises: alkaryl. incrementally adding a compound having the formula: 45 to a halosilane having the formula: NaAl(CH3)4 R'SiF to a halosilane having the formula: wherein, each R" is individually selected from the group con CHSiF sisting of hydrocarby radicals, hydrocarbyloxy radicals and the hydrogen atom, while maintaining the reaction temperature from while maintaining the reaction temperature from about 0 to about 20° C., about -20° C. to about --50 C., the amount of said compound so added being one mole the amount of said compound so added being one mole thereof per mole of said halosilane for each unit thereof per mole of said halosilane for each unit reduction in the number of atoms of fluorine per reduction in the number of atoms of fluorine per mole of silicon, mole of silicon, said amount being insufficient to replace all of the said amount being insufficient to replace all of the fluorine atoms in said halosilane, fluorine atoms in said halosilane. said reaction being conducted in tetrahydrofuran and 60 recovery of the product being performed at a tem 37. The process for the selective production of organo perature from about -20° C. to about --50° C. halosilanes which comprises: 41. The process for the selective production of organo incrementally adding a compound having the formula: halosilanes which comprises: NaAl(CH3)4 incrementally adding a compound having the formula: to a halosilane having the formula: 65 NaAlR SiCl wherein, R is individually selected from the group consist while maintaining the reaction temperature from ing of hydrocarby radicals, hydrocarbyloxy about 0° to about 20° C., radicals, halogen atoms and the hydrogen atom, the amount of said compound so added being one mole 70 at least one R being selected from the class of thereof per mole of said haiosilane for each unit re radicals consisting of alkyl, aralkyl, aryl, and duction in the number of atoms of chlorine per mole alkaryl, of silicon, said amount being insufficient to replace all of the to a halosilane having the formula: chlorine atoms in said halosilane, Ra'SiX 3,398,171 3 4. wherein, References Cited each R" is individually selected from the group consisting of hydrocarbyl radicals, hydrocarby UNITED STATES PATENTS loxy radicals and the hydrogen atom, 2,859,229 11/1958 Blitzer et al. ------260-437 X is a halogen atom, 2.921,951 1/1960 Jenkner. a is 0, 1, or 2, 3,057,894 10/1962 Robinson ----- 260-448.2 XR b is an integer of from 2-4, the total of a--b 3,137,718 6/1964 Jenkner. being 4, while maintaining the reaction temperature from FOREIGN PATENTS about -20° to about --50° C., the amount of said compound so added being one mole O 900, 132 7/1962 Great Britain. thereof per mole of said halosilane for each unit reduction in the value of b, TOBIAS E. LEVOW, Primary Examiner. said amount being insufficient to replace all of the P. F. SHAVER, Assistant Examiner. halogen atoms in said halosilane.