United States Patent (19) 11, 3,989,755 McCoy et al. (45) Nov. 2, 1976

54 PRODUCTION OF OXIMES BY THE (56) References Cited REACTION OF CARBON MONOXDE WITH UNITED STATES PATENTS NTROCOMPOUNDS 2,945,065 7/1960 Donaruma...... 260/566 A 75) Inventors: John J. McCoy, Media; John G. 3,480,672 11/1969 Kober et al...... 260/566 A Zajacek, Strafford, both of Pa.; Karl 3,734,964 5/1973 Knifton...... 260/566. A E. Fuger, Therwil, Switzerland (73) Assignee: Atlantic Richfield Company, Los Primary Examiner-Gerald A. Schwartz Angeles, Calif. Attorney, Agent, or Firm-Delbert E. McCaslin 22 Filed: Feb. 20, 1975 (21) Appl. No.: 551,487 57) ABSTRACT Related U.S. Application Data Production of oximes (and ketones) by contacting at 63) Continuation-in-part of Ser. No. 372,457, June 21, elevated temperatures and pressures, a primary or sec 1973, abandoned. ondary saturated aliphatic nitrocompound with carbon monoxide in the presence of a catalyst comprising me 52 U.S. C...... 260/566 A; 260/586 C; tallic selenium or inorganic selenium compounds and 260/586 R; 260/593 R a base. . (51 int. Cl”...... C07C 131/04 58) Field of Search...... 260/566 A, 586 A, 586 R, 20 Claims, No Drawings 260/593 R 3,989,755 2 cycloaliphatic nitrocompound is contacted with carbon PRODUCTION OF OXIMES BY THE REACTION OF monoxide at temperatures in the range of from 50° to 200 C. under pressures in the range of from 10 atmo CARBON MONOXIDE WITH NITROCOMPOUNDS spheres to 200 atmospheres in the presence of a sele nium catalyst and a base. RELATED APPLICATION It is an object of the present invention, therefore, to This application is a continuation-in-part of applica provide an improved process for the production of tion Ser. No. 372,457 filed June 21, 1973, entitled oximes. PRODUCTION OF OXIMES BY THE REACTION It is another object of this invention to provide a OF CARBON MONOXIDE WITH NITROCOM 0 process for the production of oximes and ketones. POUNDS now abandoned. It is another object of this invention to provide an efficient process for the production of oximes that FIELD OF INVENTION minimizes the formation of undesirable by-products. The present invention relates to a process for the It is another object of this invention to provide an manufacture of oximes (and ketones) by the reaction 15 efficient, high yield process for the production of an of carbon monoxide with a primary or secondary satu efficient, high yield process for the production of ox rated aliphatic nitrocompound, or a saturated cycloali imes from the reaction of primary or secondary satu phatic nitrocompound under elevated temperature and rated aliphatic nitrocompounds, or a saturated cycloal pressure conditions in the presence of a catalyst and a iphatic nitrocompound by using metallic selenium, or base. inorganic compounds of selenium or combinations Oximes are an important class of organic compounds thereof as a catalyst in conjunction with a base. and are of significant importance in industrial chemis It is another object of this invention to provide a try. Cyclohexanone oxime, for example is used as an process for the production of oximes which uses readily intermediate in the manufacture of caprolactam, an available, low cost starting materials. important fiber precursor, by the Beckmann rearrange 25. These and other objects of the invention will become ment. Other oximes, such as acetoxime, can be used as apparent from the following description of the process a source of the oxime moiety, instead of using hydrox and from the claims. ylamine itself. This can overcome the many disadvan tages in handling hydroxylamine solutions, and in the DESCRIPTION OF THE PROCESS subsequent workup of its reaction mixtures. Other 30 In the instant process the nitrocompound is, in gen open chain oximes such as methyl ethyl ketoxime, eral, largely converted to the oxime. In some cases, butyraldoxime, etc. are used commercially as anti-skin however, depending on the starting nitrocompound ning agents in paints. and the particular reaction conditions employed, the Although methods are available for the reduction of corresponding ketone can be formed. For example, aliphatic nitrocompounds to oximes, they have a num 35 when nitrocyclohexane is reacted under the conditions ber of disadvantages not found in the instant process. of this process to prepare cyclohexanone oxime, cyclo For example, in U.S. Pat. No. 3,480,672 there is de hexanone can be formed as a by-product. This ketone scribed a process for the reduction of aliphatic nitro can be easily converted to the oxime by reaction with compounds using carbonyl sulfide as a reducing agent. hydroxylamine or, if desired, simply separated from the This process requires the use of a large molar excess of 40 cyclohexanone oxime by any number of suitable sepa toxic carbonyl sulfide as compared to the starting nitro ration techniques. compound, gives a relatively low conversion for the Suitable nitrocompounds for the process of this in quantity of carbonylsulfide used and, apparently, is not vention are primary or secondary saturated aliphatic a catalytic reaction. In U.S. Pat. No. 2,945,065 there is mononitrocompounds and saturated cycloaliphatic described a method by which nitrocyclohexane is re 45 mono-nitrocompounds. The term "saturated' herein duced to the oxime by reaction with carbon monoxide refers to compounds which contain no olefinic or acet at an elevated temperature and pressure. However, this ylinic bonds but does not exclude the arylalkyl nitro process requires that the nitrocyclohexane be con compounds. Substituted or unsubstituted nitroalkanes verted to an alkaline nitronate salt in a previous and which are suitable include nitromethane, nitroethane, separate step. Further, this process requires the use of 50 1-nitropropane, 2-nitropropane, l-nitrobutane, 2 anhydrous conditions, an alkanol as a solvent (some of nitrobutane, 1-nitropentane, 1-nitro-1-methylpropane, which is also consumed as a reactant), and a higher 1-nitro-3-methylpropane, 2-nitro-3-ethylbutane, 1 temperature to achieve a convenient reaction rate than nitro-2,2-dimethylbutane, 1-nitro-3-methylbutane, 2 is required by the instant process. In U.S. Pat. No. nitro-4-methylpentane, 1-nitrohexane, 3-nitro-4,5- 3,734,964 there is described a method for partial re 55 dimethylhexane, 3-nitrododecane, nitrooctadecane, duction of a nitroparaffin to the corresponding oxime 5-nitro-7,8-dimethyloctadecane, and the like. Also using critical ratios of a copper salt catalyst, nitroge suitable are the nitrocycloalkanes such as nitrocyclobu nous base and water. This process requires that a base tane, nitrocyclopentane, nitrocyclohexane, nitrocy copper catalyst complex be formed and then passing cloheptane, nitrocyclooctane, nitrocyclododecane and carbon monoxide into a reaction mixture of the formed 60 the like including the alkyl substituted or halo substi complex and nitroparaffin. Other methods, well known tuted compounds. Likewise the aryl nitroalkyl com in the art, employing hydrogen as a reducing agent are pounds such as phenyl nitromethane, p-bromo-phenyl complicated by the undesirable reduction of the oxime nitromethand, p-toluyl nitromethane and the like are to an amine. suitable. These are merely representative of the com 65 pounds suitable, since in general any nitrocompound of SUMMARY OF THE INVENTION the types described containing up to 20 carbon atoms In accordance with this invention a primary or secon can be employed including mixtures of such nitrocom dary saturated aliphatic nitrocompound or saturated pounds. 3,989,755 3 4 Catalysts for use in this invention include selenium. It will be understood from the foregoing disclosure In addition, various compounds containing selenium that all of the disclosed catalysts, solvents and bases are can be used alone or in combination with selenium operable with all of the nitrocompounds disclosed for metal. One of the simpletstand least expensive forms of the production of the oximes. It will be distinctly under Selenium is the metal itself which can be as good, if not 5 stood, however, by those skilled in this art that every better, than most selenium compounds. Nevertheless, combination is not equally effective in maximizing good yields can be obtained with such compounds as Oxime production from a particular nitrocompound Selenium dioxide, titanium diselenide, sodium selenite, starting material since these vary widely in their reac Zinc selenite, zinc selenide, tungsten selenide, selenium tivity. sulfide and selenium disulfide. 10 The catalyst of this invention is preferably used in The catalyst material, as indicated above, can be molar ratios of 2:1 to 1000:1 of the nitrocompound to self-supported or the catalyst material can be deposited catalyst. Preferably, the molar amounts of the nitro on a support or carrier for dispersing the catalyst to compound to catalyst is in the range of from 5:1 to increase its effective surface. Alumina, silica, carbon, 100:1. It will be understood, however, that larger or asbestos, bentonite, diatomaceous earth, fuller's earth, 15 smaller amounts of catalyst can be used. The ratio of and analogous materials are useful as carriers for this base to nitrocompound can range from 0.01:1 to 10:1, purpose. Preferably, the carrier selected is one which is however, larger or smaller amounts can be used, for inert in the described process. example, when an amine is used as both solvent and A base must also be added to the reaction. Organic base the quantity of base is of necessity far in excess of bases, metal salts of carboxylic acids and metal hydrox 20 the molar quantity of the catalyst or of nitrocompound ides have been found to be effective. Organic bases since it must be and is sufficient to dissolve the nitro suitable for the reaction are tertiary amines such as compound. triethylamine, pyridine, quinoline and N,N-dime The order of mixing the reactants is not critical and thylaniline. Other amines, such as secondary amines, can be varied within the limitations of the equipment exemplified by diethylamine are also suitable. Thus, 25 employed. A simple procedure is to charge the nitro aliphatic, aliphaticaromatic and aromatic heterocyclic compound, the solvent, catalyst and base in the desired amines can be employed in this reaction. Not all amines quantities into the reaction vessel, introduce the proper of the group described are equivalent to one another in amount of carbon monoxide and then heat the mixture their ability to affect high yields of oximes. In general, to obtain the desired reaction. A suitable pressure ves those amines which are stronger bases give higher 30 sel, such as an autoclave, which is preferably provided yields than those which are classed as weak bases. with heating means and agitation means, such as a Thus, triethylamine is preferred over pyridine as an stirrer or an external rocking mechanism, is employed organic base. It is important to note, however, that the for the reaction. choice of base and base strength used to affect high Generally, the amount of carbon monoxide in the yields of oximes is dependent on the starting nitrocom 35 free space of the reactor is sufficient to maintain the pound. There are examples in which a base not strongly desired pressure, as well as to provide a reactant for the effective for one nitrocompound can prove very effec process. As the reaction progresses, additional carbon tive for another nitrocompound. monoxide can be fed to the reactor either intermittenly Compounds normally considered as weak bases, such or continuously. Although greater and lesser amounts as the metal salts of carboxylic acids, can also be em 40 of carbon monoxide can be employed if desired, gener ployed to good advantage. Examples of such com ally the total amount of carbon monoxide added during pounds are lithium acetate, sodium acetate, potassium the reaction is between about 3 moles and about 50 acetate, calcium acetate, sodium formate, lithium for moles and preferably between about 5 moles and about mate and antimony triacetate. The acid salts can be 15 moles of carbon monoxide per mole of nitrocom added preformed or can be generated "in situ' by 45 pound. adding appropriate quantities of the corresponding The reaction temperature is generally maintained in acid and base. There is no limit on the type of acid used the range of from 50 to 200 C. and preferably within or the corresponding metal oxide or hydroxide em the range of from 80 to 150° C. These temperature ployed. If desired, metal hydroxides or oxides, them ranges permit a convenient rate of reaction to be selves, can be used as bases. 50 achieved, while avoiding undesirable side reactions. It While the process of the invention can typically be will be understood, however, that any elevated temper operated effectively in the absence of a solvent, a sol atures below that at which the starting materials or the vent can be employed. Use of a suitable solvent such as products decompose can be used. The reaction is car benzene, toluene, xylene, aliphatic halogenated hydro ried out, as indicated above, at superatmospheric pres carbons, halogenated aromatic hydrocarbons can be 55 sures which is normally between about 10 and about used. In addition, ether solvents such as tetrahydrofu 200 atmospheres, although higher or lower reaction ran, 1,4-dioxane, 1,2-dimethoxyethane and the like are pressures can be employed if other reaction conditions effective. Alcohols can also be used as solvents such as are suitably adjusted. Preferably, however, only moder methanol, ethanol, isopropanol and tert-butanol. A ate carbon monoxide pressures in the range of about 10 particularly advantageous and preferred solvent is one 60 to about 60 atmospheres are employed and the reac of the tertiary amines previously described. Such a tion is conveniently run at a temperature of below solvent can also act as the necessary base. about 150°C. within this pressure range. Combinations of an amine solvent such as pyridine While the reaction of the present invention is nor with an additional amine base such as triethylamine can mally carried out batchwise, if desired, the reaction can be particularly effective for certain nitrocompounds, 65 be carried out semi-continuously or even continuously. while with other compounds such a combination offers The reaction time is dependent upon the nature of the no distinct advantage and a solvent such as pyridine is reactants, temperature, pressure and the type of cata also suitable as the base. lyst employed, as well as the type of equipment which 3,989,755 S 6 is used. In general, however, reaction times ranging from 0.25 to 4.0 hours can be used. The shorter times EXAMPLE I with the more active catalysts, more reactive nitro.com Each run was carried out in a 300 ml. capacity 316 pounds or more severe reaction conditions, while the Stainless Steel rocking autoclave. The conditions (ex longer times are associated with less active catalysts, 5 cept where noted otherwise) were: 0.5 g. selenium the less reactive nitrocompounds, and the less severe (metallic powder); initial charge of 800 psig carbon reaction conditions. For most reactions, times from 0.5 monoxide, 5.0 g nitro-cyclohexane; reaction tempera to 2.0 hours can be used. ture, 130 C.; time, 1 hour. The results and remarks are After the reaction has been completed, the tempera shown in Table I. The ketone produced was cyclohexa ture of the reaction mixture can be dropped to room 10 none and the oxime produced was cyclohexanone ox temperature and the pressure vessel vented. The reac- ime. TABLE I Run Solvent Base: Mole % Mole % Set. to No. ml g Conv. Ketone Oxime Remarks Pyridine EA3) 3. m m No selenium, comparative run. 75 3.6 g. 2 Tetrahydrofuran TEA 39.2 5.2 38.8 Shows use of ether solvent with 75 3.6 g amine base. 3 Ethyl Alcohol TEA 76.7 8.7 26.9 Alcohol solvent with amine base. 75 3.6 g. i' 4 Pyridine TEA 78.5 4.2 42.4 Combination pyridine solvent with 75 3.6 g amine base - best conversion and - yield among these runs. 5 Pyridine TEA 64.3 m 47.4 2 hour run. 75 3.6 g 6 Pyridine --- 7.3 14.9 48 Low conversion shows pyridine is 75 not preferable as both base and - : solvent with nitrocyclohexane. 7 Pyridine --- 23. 5.0 25.0 Temp. 170', higher temperature 75 do not improve pyridine as both solvent and base. 8 CHOH TEA 24.3 - 9.5 Reaction temp. 70° C. 75 0.72 g 9 CHOH TEA3) 78.0 440 22.5 Reaction temp. 100 C. - higher 75 0.72 g yield of ketone with CHOH solvent. () Pyridine TEA 58.6 m 7.6 Reaction temp. = 100° C. 75 0.72 g l CHOH KOH(4) 100.0 45.2 m No oxime with this solvent - 75 1.0 g base combination. 2 CHOH KOAc. HO 88.8 31.4 5.8 Low oxime yield with CH-OH again. 75 1.0 g 13 Pyridine KOH 70.5 27.1 39. Pyridine - KOH - higher yield of 75 1.0 g oxime. 4. Pyridine TEA 70.5 r 23.4 increasing amount of TEA decreases 75 1.45 g conversion slightly, but greatly increases yield. 5 Pyridine TEA 63.8 8.0 28.3 increasing amount of TEA decreases 75 7.2 g conversion slightly, but greatly increases yield. 16 Pyridine TEAC) 61.2 m 50.6 Increasing amount of TEA decreases 75 18.0 g conversion slightly, but greatly increases yield. 17 Pyridine TEA 58.6 -- 30.8 0.1 g HO added - decreased con 75 3.7g version. 18 CHOH TEA 76.7 40.4 16.8 0.1 g HO added. 75 0.72 g . 19 Pyridine DEA(6) 56.0 --- 15.7 Secondary amine base. 75 2.6 g. Footnotes: '''Conv. = molc per cent of nitrocompound converted. Sci. = mole per cent of ketone and oximc produced based on amount of nitrocompound convert.cd. TEA = tricthylaminc. KOH = potassium hydroxide. KOAc. HO = potassium acctate monohydrate. “DEA = dicthylamine. tion product is then treated by conventional proce-55 dures, including filtration, distillation, or other suitable EXAMPLE II separation techniques, to effect separation of the oxime Two runs were carried out on 2-nitropropane giving from unreacted starting material, solvent, by-product, acetoxime and acetone. The same equipment was em catalyst and other material which may be present. ployed as in Example I utilizing: 0.5g selenium; initial The following examples set forth in tabular form the 60 charge of 800 psig CO; 5.0 g 2-nitropropane; reaction conditions and results obtained in a series of typical temperature, 150° C.; time, 1 hour. The results are runs. These are not to be construed as limiting the shown in Table II. invention solely to their disclosure. TABLE II Run Solvent Base Mole % Mole % Sel. to No. m Conv. Ketone Oxime Remarks 20 Tetrahydrofuran TEA" 40.3 --- 86.9 150° C. 75 - 3.6 g. 3,989,755 7 TABLE II-continued Run Solvent Base Mole % Mole % Sel. to No. m 2 Conv., Ketone Oxime Remarks 21 Pyrigine - 56.1 3. 87.5 150° C. - note pyridine here adequate as the base as well as the solvent. Footnotes: 'Conv. = mole per ccnt of nitrocompound convcrtcd. 'Scl. s. mole per cent of ketone and coxime produced based on amount of nitrocompound converted. “TEA = tricthylamine,

EXAMPLE VI It will be seen from the data in the foregoing exam Fifty milliliters of tetrahydrofuran, 50 milliliters of ples that methyl alcohol is not a preferred solvent for 15 triethylamine, 5.0 grams nitrocyclohexane and 1.5 oxime production, in general, it favors the production grams sodium selenite were charged to the autoclave. of the ketone instead of the oxime, irrespective of the After pressuring to 800 psig with carbon monoxide it base employed. The combination of pyridine as the was heated to 120° C. for 1 hour. A nitrocyclohexane solvent (which is basic) with a stronger organic base conversion of 43 per cent was found with a selectivity such as triethylamine gives the best conversion and 20 to cyclohexanone oxime of 54 per cent. yield of the oxime from nitrocyclohexane with the opti mum being shown in Run No. 4 as compared with Nos. EXAMPLE VII 14, 15 and 16. Five grams of nitrocyclohexane, 50 milliliters of pyri The amount of solvent in each of the runs shown was dine, 50 milliliters of triethylamine, 0.25 gram selenium the same for purposes of comparison, i.e. 15 ml solvent 25 metal and 0.31 gram selenium dioxide were charged to per gram of nitrocompound, however this was merely the autoclave. After pressuring to 800 psig with carbon for experimental convenience and amounts ranging monoxide it was heated to 150° C. for 1 hour. Analysis from about 2 ml of solvent per gram of nitrocompound of the reaction solution by gas chromatography showed to 30 ml per gram also is a convenient range. It will be a conversion of nitrocyclohexane of 75 per cent with a understood, however, that the amount of solvent 30 selectivity to cyclohexanone oxime of 52 per cent. should always be sufficient to dissolve completely the We claim: nitrocompound. Very large amounts of solvent do not 1. A method for the production of a material selected have any benefit and merely add to the cost of process from the group consisting of an oxime, a ketone and 1ng. mixtures thereof which comprises contacting a nitro The following examples set forth the conditions and 35 compound containing up to 20 carbon atoms selected results obtained employing various selenium com from the group consisting of primary saturated ali pounds as the catalyst. In each example the process was phatic mono-nitrocompounds, secondary saturated carried out in a 300 ml capacity 316 Stainless Steel aliphatic mono-nitrocompounds and saturated cycloal rocking autoclave. iphatic mono-nitrocompounds with carbon monoxide 40 at a pressure in the range of from 10 atmospheres to EXAMPLE III 200 atmospheres, at a temperature in the range of from Five grams of nitrocyclohexane, 50 milliliters of pyri 50 to 200 C. in the presence of a catalyst selected dine, 50 milliliters of N,N-dimethylaniline and 1.0 gram from the group consisting of metallic selenium, inor selenium dioxide were charged to the autoclave. After ganic compounds of selenium selected from selenium pressuring to 800 psig with carbon monoxide it was 45 dioxide, titanium diselenide, sodium selenite, zinc sele heated to 150° C. for 1 hour. Analysis of the reaction nite, zinc selenide, tungsten selenide, selenium sulfide solution by gas chromatography showed a conversion or selenium disulfide, and combinations thereof and in of nitrocyclohexane of 73.5 per cent with a selectivity the presence of a base selected from the group consist to cyclohexanone oxime of 48 percent. ing of aliphatic amines, aliphatic-aromatic amines, aro 50 matic heterocyclic amines, metals of carboxylic acids EXAMPLE IV and metal hydroxides. To the 300 milliliter autoclave were charged 5.0 2. The method according to claim 1 wherein said grams nitrocyclohexane, 50 millileters of pyridine, 50 mono-nitrocompound is a primary saturated aliphatic milliliters of triethylamine and 1.0 gram titanium nitrocompound. diselenide. The autoclave was sealed, pressured to 55 3. The method according to claim 1 wherein said 1000 psig with carbon monoxide and heated to 120°C. mono-nitrocompound is a secondary saturated ali for 1 hour. A conversion of nitrocyclohexane of 85 per phatic nitrocompound. cent with a selectivity to cyclohexanone oxime 54 per 4. The method according to claim 3 wherein said cent was obtained. secondary nitrocompound is 2-nitropropane. 60 5. The method according to claim 1 wherein said EXAMPLE V mono-nitrocompound is a saturated cycloaliphatic ni Five grams of 2-nitropropane, 50 milliliters of pyri trocompound. dine, 50 milliliters of triethylamine and 1.0 gram sele 6. A method according to claim 5 wherein said nitro nium disulfide were charged to the autoclave. After compound is nitrocyclohexane. heating for one hour at 150° C. with 1200 psig carbon 65 7. The method according to claim 1 wherein the monoxide a conversion of 2-nitropropane of 60 per pressure is in the range of from 10 atmospheres to 60 cent with a selectivity to acetoxime of 85 per cent was atmospheres and the temperature is in the range of obtained. from 80° to 50° C. 3,989,755 10 8. The method according to claim 1 wherein said ing nitrocyclohexane with carbon monoxide at a pres amine base is pyridine. sure in the range of from 10 atmospheres to 200 atmo 9. The method according to claim 1 wherein said spheres, at a temperature in the range of from 50° to amine base is triethylamine. 200 C. in the presence of a catalyst selected from the 10. The method according to claim 1 wherein said 5 group consisting of metallic selenium, inorganic com amine base is diethylamine. pounds of selenium selected from selenium dioxide, 11. The method of claim 1 wherein said amine base is titanium diselenide, sodium selenite, zinc selenite, Zinc N,N-dimethylaniline. selenide, tungsten selenide, selenium sulfide or sele 12. The method according to claim 1 wherein said nium disulfide, and combinations thereof and in the metal salt of the carboxylic acid is potassium acetate. 10 presence of a base selected from the group consisting 13. The method according to claim 1 wherein said of aliphatic amines, aliphatic-aromatic amines, aro metal hydroxide is potassium hydroxide. matic heterocyclic amines, metal salts of carboxylic 14. The method according to claim 1 wherein said acids and metal hydroxides. mono-nitrocompound is dissolved in a solvent. 19. The method according to claim 18 wherein said 15. The method according to claim 1 wherein said 15 catalyst is metallic selenium and said base is selected catalyst is metallic selenium. from the group consisting of pyridine, triethylamine, 16. A method according to claim 1 wherein said diethylamine, potassium acetate and potassium hydrox catalyst is an inorganic compound of selenium. ide. 17. A method according to claim 1 wherein said 20. A method according to claim 18 wherein said catalyst is an inorganic compound of selenium and said 20 catalyst is an inorganic compound of selenium selected base is selected from the group consisting of pyridine, from the group consisting of selenium dioxide, titanium N,N-dimethylaniline and triethylamine. diselenide and sodium selenite and said base is selected from pyridine, triethylamine or N,N-dimethylaniline. 18. A method for the production of cyclohexanone k k ck k oxime and cyclohexanone which comprises a contact 25

30

35

40

45

50

55

60

65