Patented Apr. 3, 1951 2547,686

UNITED STATES PATENT of FICE PREPARATION oF sUCCINoNITRILE Charles E. Brockway, Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N.Y., a. corporation of New York No Drawing. Application December 2, 1949, Serial No. 130,866 5 Claims. (CI. 260-465.8) 2 This invention relates to the preparation of -a- line earth metal hydroxides such as sodium, succinonitrile and more specifically pertains to potassium and calcium hydroxides and salts of the preparation of succinonitrile by reacting strong bases with weak acids such as Sodium or (vinyl cyanide) with a ketone cy. potassium carbonates, cyanides, acetates, propi anohydrin. - onates, benzoates, etc. However, other basic mar Acrylonitrile is a well known cyanoethylating terials including primary and secondary amines 'agent reacting with the active hydrogen of an such as ethyl amine, dimethyl amine, ethylene OH group of many organic compounds to pro diamine, diethylene triamine, cyclohexyl amine, “duce the corresponding cyanoethyl derivatives. benzyl amine, ethanol amine, aniline, etc. are For example, aldehyde cyanohydrins such as also suitable, it being understood that basic ma glyconitrile and lactonitrile react with acrylo terials in general are operative. The amount of to form cyanoethyl derivatives. Accord basic catalyst used is likewise not a critical factor ingly, it was to be expected that reaction between and may be varied considerably with the ma acrylonitrile and a ketone cyanohydrin would also terial used but in general from 0.5 to 5% of cata result in cyanoethylation of the hydroxyl group 5 lyst based on the total Weight of the reactants is according to the following equation: employed. As indicated by the last written equation above (N ...... CN any desired ketone cyanohydrin can be employed: R-C-OH + CH=CHCN - R-C-O-CHCH.CN However, since the ketone residue of the cyano k, k, 20 hydrin is recovered during the reaction and since aromatic ketones such as acetophenone, benzo where R1 and R2 are hydrocarbon radicals. phenone and the like are high boiling liquid or I have discovered, however, that ketone cyano solid materials which are rather difficultly sepa hydrins, react with acrylonitrile in the presence rated from the succinonitrile, it is preferred that of a basic material as catalyst to form succino :25 the ketone cyanohydrin employed be an aliphatic nitrile rather than the expected cyanoethyl de or alicyclic ketone cyanohydrin. Best results are rivatives. The reaction to form the succinonitrile obtained when using ketone cyanohydrins of the proceeds as follows: structure R/S CN + CH=CHCN - R} + NHi-li, (N 30

R OB R.

35 wherein each of R1 and R2 represents an alkyl or cycloalkyl radical Or Wherein R1 and R2 come bined represent a cycloalkylene radical and

sequently, the ketone can be recovered and re wherein the number of carbon atoms in Ri and acted with to reform the cyano R2 combined is between 2 and 12. Specific ex hydrin for further use as a reactant...... 40 amples of preferred aliphatic and alicyclic ketone The basic material which is employed as cata cyanohydrins include actOne cyanohydrin, meth lyst in the process of this invention is not critical yl ethyl ketone cyanohydrin, methylbutyl ketone and may be either inorganic or organic. Espe cyanohydrin, methyl isobutyl ketone cyanohy cially suitable are tertiary amines such as tri drin, methyl propyl ketone cyanohydrin, methyl methylamine, triethylamine, tributyl amine, tri isopropyl ketone cyanohydrin, methyl amyl cyclohexyl amine, tribenzyl amine, hexamethyl ketone cyanohydrin, methyl isoamyl ketone cy ene tetramine, pyridine, triethanol amine and anohydrin, methylhexyl ketone cyanohydrin, di the like; ammonium hydroxide and quaternary ethyl ketone cyanohydrin, ethyl propyl ketone ammonium bases such as trimethylbenzyl am cyanohydrin, ethyl isopropyl ketone cyanohy moniumhydroxide and the like; alkali and alka 50 drin, ethylbutyl ketone cyanohydrin, ethyl isos 2,547,686 ...... 3 4. butyl ketone cyanohydrin, ethyl amyl ketone cy would drop and refluxing would cease as SOOn as anohydrin, ethyl isoamyl ketone cyanohydrin, the external source of heat was removed thus in ethylhexyl ketone cyanohydrin, dipropyl ketone dicating completion of the reaction. The mixture cyanohydrin, diisopropyl ketone cyanohydrin, resulting from the reaction was cooled rapidly to propyl isopropyl ketone cyanohydrin, propylbutyl room temperature and the basic catalyst, Sodium ketone cyanohydrin, isopropyl butyl ketOne cy hydroxide, was neutralized with 2.5 parts of 85% anohydrin, propyl isobutyl ketone cyanohydrin, phosphoric acid. This mixture was transferred to isopropyl isobutyl ketone cyanohydrin, propyl a still pot and fractionated. The following frac amyl ketone cyanohydrin, isopropyl amyl ketone tions were recovered: cyanohydrin, propyl hexyl ketone cyanohydrin, 10 isopropyl hexyl ketone cyanohydrin, the butyl Fraction Boiling Point Parts amyl ketone cyanohydrins, the butyl hexylketone cyanohydrins, the diamyl ketone cyanohydrins, 155°C. to 63° C. at atmos. pressure...... ------50.6 2 63 C. to 137 C. at 12 Inn. Eg------. 6. the amyl hexyl ketone cyanohydrins, the dihexyl 95° C. to 125 C. at 1.0 min. Eg------E; ketone cyanohydrins, dicyclopentyl ketone cy Black Resin Residue------anohydrin, dicyclobutyl ketone, cyanohydrin, di cyclohexyl ketone cyanohydrin, methyl cyclo propyl ketone cyanohydrin, methyl cycloperatyl Fraction.1 was identified as containing predomi ketone cyanohydrin, methyl cyclohexyl-ketone nantly acetone. Fraction 3 was a nearly colorless cyanohydrin, ethyl isopropyl ketone cyanohy 20 waxy cake representing an 85% yield of succino drin, propyl cyclohexyl ketone cyanohydrin, iso nitrile with a clear point of 53° C. (the clear point propyl cyclohexyl ketone cyanohydrin, butyl cy being...that temperature at which a Small sample clohexyl ketone cyanohydrin, isobutyl cyclohexyl of the material became completely clear when ketone cyanohydrin, amyl cyclohexyl ketone cy 3 slowly heated in a Small test tube). The clear anohydrin, n-hexyl cyclohexyl ketOne cyanohy 25 point remained unchanged when a portion of drin, cyclobutanone cyanohydrin, cyclopentanone fraction-3 was mixed with a portion of pure, suc cyanohydrin and -cyclohexanone cyanohydrin. cinonitrile having a clear point of 57°C. A sample The process of forming succinonitrile is readily of fraction 3 was hydrolyzed to yield a material and conveniently: carried out by combining acry having a melting point of 186°C. to 187°C., the Ionitirile and the ketone cyanohydrin in any de 30 melting point of succinic acid. Consequently, the sired proportions but preferably in Substantially material called-fraction 3 was succinonitrile. . equimolecular proportions, adding a basic cata The clear point. described above was employed lyst, heating the resulting mixture. until reaction as a means for determining the purity of succino begins and then controlling the reaction tem nitrile prepared by my process. Redistilled 35 authentic. Succinonitrile was found to have a clear perature within the range of 50° C. to 150°C. un point of 57°C. Known quantities of acetone til the reaction is "complete. Since the reaction cyanohydrin were added to the redistilled mate is exothermic, the completion of the reaction is rial. and the depression of the clear point was evidenced by the cessation of heat liberation. determined. The following table gives the results After the reaction is complete, the mixture is of these findings. preferably cooled to room temperature and the :40 basic catalyst neutralized. Then succinonitrile is Table I recovered from the reaction" mixture in any de sired manner. In the preferred method the re Percent by action mixture is distilled, employing reduced Weight of Clear Point Cyano Degrees pressure where necessary to reduce decomposition hydrin Centigrade and charring, to separate and recover the various components of the mixture. In this manner Suc ,57 cinonitrile in excellent yield and in a high degree 55 of purity is obtained. 53 The following specific examples are given to i50 50 illustrate the detailed practice of this invention as well as "to illustrate the various modifications By using the above tabulated clear points it is which are Within its scope. In all of the examples apparent that the succinonitrile prepared in Ex the parts are parts by weight. ample I with a clear point of 53° C. contained little Eacample I 55 impurities, no more than 2%. The Succinonitrile To a reactor equipped with a mechanical stirrer, also of high purity, as will be apparent. a reflux condenser, a thermometer and a means for heating and cooling its contents, there was EXAMPLES II TO XII added 53 parts df acrylonitrile, 85 parts of acetone 60 cyanohydrin, and 1.4 parts of sodium hydroxide In. Examples.II to XII, the method as used in (1.0% by weight based on the total reactants) Example, I was employed with the footnoted ex dissolved in 14 parts. Of Water. The mixture was ceptions shown in Table II. The reactants, acrye stirred and slowly heated to 65° C. Where spon lonitrile and ketone cyanohydrin, were employed taneous reflux began. Although heating of the 65 in equimolecular proportions as in Example I. reactants' was stopped, the reaction temperature The pertinent reaction data, as well as the results rose to 18°C. in 25 minutes during which time it of these examples...are tabulated below in Table was necessary to cool the reactants intermittently II: The identity of the succinonitrile formed in to maintain and control the reflux rate. The ori each example was established by the clear point ginal colorless mixture's gradually changed to a 70 of the product, the mixed clear point with au dark-red-brown during the reaction. As the reac thentic-succinonitrile and by hydrolysis of part tion decreased in intensity, heat Was again applied of...each product to succinic acid. In each case to maintain a reaction temperature of about 75°. C. a ketOne corresponding to the original, ketone to 80°C. for, an additional.25 minutes after which cyanohydrin temployed was also recovered from time the temperature of the reaction mixture 75 the reaction mixture......

2,547,686 Table II ACRYLONITRILE REACTED WIT KETONE CYANOHYDRIN

Reaction Succinonitrile

EleOe CyagyinetOne of Catalyst, pe;Ota s reactantsby weight, based on Per

TET";P Yieldit SS

II------Acetone.------Triethylamine, 2%------42 67-78 74 OC. 56 III------do------NaOH.1%------48 65-75 85 53 IV------do------Tgethylbenzylammonium-hydroxide, 29 67-75 86 50 V------do...... Kico, 9%------. 34 67-75 83 53 VI------do------NaCN, 2%------47 63-76 85 53 VII?------s--do------Ca(OH)2, 2%------92 65-74 17 49 VIII -- Mix Ethyl Ke- Triethylamine, 2%------55 65-92 78 57 One IX------do------NaOH, 1%------35 64-91 83 54 X------M; n-Flexyl Ke- K2CO3, 2%------61 68-105 88 49 O8. w XI.------Methyl Isopropyl NaOH, 1%------42 71-93 88 52 Ketone. XII------Cyclohexanone.------NaON, 2%------107 73-95 95 45 1 Catalyst not neutralized before distillation because basic catalyst was volatile. 2 Heat applied during entire reaction. As illustrated by Examples II and VIII, when based on the total reactants of a basic material a volatile basic catalyst is employed in the proc 25 as a catalyst and recovering the succinonitrile ess, it is not necessary to neutralize the base be thus formed. - fore distillation to recover the succinonitrile. 4. The method of preparing succinonitrile . The volatile base can be removed with one of the which comprises preparing a reaction mixture oW boil fractions and re-used. When a non containing acrylonitrile, a ketone cyanohydrin volatile base is employed as catalyst, however, it 30 selected from the class consisting of aliphatic and is preferably neutralized since the presence of alicyclic ketone cyanohydrins, and a basic cata basic material during the later stages of distilla lyst, maintaining the said mixture at a tempera tion may tend to cause resinification of succino ture of 50 to 150° C. whereupon chemical reac nitrile with a needless increase in loss of the de tion occurs to form succinonitrile and a ketone sired product. 35 corresponding to the original ketone cyanohy Having described my invention by means of drin, and finally fractionally distilling the mix specific examples, I do not thereby desire or in ture to separate and recover the succinonitrile tend to limit myself solely thereto, for as herein and the said ketOne. - before stated the proportions of reactants and 5. The method of claim 4 wherein the cyano reaction conditions employed may be varied and 40 hydrin is and the basic equivalent chemical compounds may be employed catalyst is sodium hydroxide. as set forth herein without departing from the CHARLES E, BROCKWAY. Spirit and scope of the invention as defined in the appended claims. REFERENCES CTED I claim: 45 1. The method of preparing succinonitrile The following references are of record in the which comprises reacting acrylonitrile with a file of this patent: ketone cyanohydrin selected from the class con UNITED STATES PATENTS sisting of aliphatic and alicyclic ketOne cyano Number Name Date hydrins in the presence of a basic catalyst at a 0 2,205,239 Carter et al.------June 18, 1940 temperature from 50° C. to 150° C. and recover 2,397,341 Ellingboe ------Mar. 26, 1946 ing the succinonitrile thus formed. 2,434,606 Carpenter ------Jan. 13, 1948 2. The method of preparing succinonitrile 2,460,603 Semon ------Feb. 1, 1949 which comprises reacting acrylonitrile with ace tone cyanohydrin in the presence of a basic cata 55 FOREIGN PATENTS lyst at a temperature from 50° C. to 120° C. and Number Country Date recovering the succinonitrile thus formed. 707,852 Germany ------July 5, 1941 3. The method of preparing succinonitrile OTHER REFERENCES which comprises reacting acryonitrile with ace tone cyanohydrin at a temperature from 50° C. 60 Migrdichian: "Chem. Of Org. Cyanogen to 120° C. in the presence of 0.5% to 5% by weight Comp'ds,' (Reinhold), p. 174, 1947.