STATES PATENT OFFICE 2,454,047 CONVERSION of ALICYCLIC ALDEHYDES Harry Do V
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Patented Nov. 16, 1948 2,454,047 UN STATES PATENT OFFICE 2,454,047 CONVERSION OF ALICYCLIC ALDEHYDES Harry do V. Finch, El Cerrito, Seaver A. Ballard, Orlnda, and Theodore W. Evans, Oakland, Calif., assignors to Shell Development Com pany, San Francisco, Calif., a corporation of t Delaware No Drawing. Application May 9, 1947, Serial'No. 747,128 20 Claims. (Cl. 260-514) i 2 . ., This invention relates to a process for the con aldehydes. The alcohols produced in the course version of alicyclic aldehydes, the production of of the present process, as hereinafter described, alicyclic acids and alcohols, and the production are of a new and useful variety. of aliphatic dicarboxylic acids. More particu The present invention provides an e?icient and larly, this invention provides a process whereby economical process for producing dicarboxylic alicyclic aldehydes may be converted simultane acids which obviates the objections to prior art ously to alicyclic acids and alcohols, and whereby processes, and which is especially adaptable to the.v the alicyclic acids so produced may be further commercial production thereof, and in the course acted upon to produce aliphatic dicarboxylic of which alicyclic acids and new and valuable acids. alicyclic alcohols are produced. I ‘ Certain reactions for the conversion of alde According to our invention, more fully de hydes to acids are well known, and various proc- ~ scribed hereinafter, an alicyclic aldehyde is con esses for these reactions have been described. tacted with a substantially anhydrous molten or However, these heretofore known reactions are "fused” alkali metal hydroxide, or mixture of two not generally applicable to alicyclic aldehydes, 25 or more alkali metal hydroxides. The resulting especially where the alicyclic aldehyde contains alkali metal carboxylate may or may not be sep one or more unsaturated linkages of ole?nic char arated from the reaction mixture. If separated. acter. between two nuclear carbon atoms, since it constitutes a valuable product which may be the necessary reagents or reaction conditions converted by methods known to the art to the commonly cause ring cleavage in such cases, corresponding acid if desired, or it may be further. thereby precluding formation of alicyclic acids, acted upon with an aqueous solution of an alka‘ and usually result in the formation of an aliphatic line material, as hereinafter fully described, to monocarboxylic acid. Accordingly, it is an object produce the salt of an aliphatic dicarboxylic acid. of the present invention to provide a process for This salt may be converted, also by methods the conversion of alicyclic aldehydes, and espe 25 known to the art, to the corresponding-acid if cially those alicyclic aldehydes having at least one desired. If the alkali metal carboxylate is not unsaturated linkage ofole?nic character between separated from the reaction mixture, the salt of ‘ two nuclear carbon atoms, to alicyclic acids. A a dlcarboxyllc acid, and subsequently the dicar further object is the production of alicycllc alco boxylic acid, may be prepared directly therefrom hols in the same step of the process. A further 80 by treating the reaction mixture with watenwlth object, is to react the alicyclic acids so produced adjustment of the concentration of the alkali if so that aliphatic dicarboxylic acids are produced. necessary and heating the resulting mixture, as A further object is to produce aliphatic dicar hereinafter described. The aliphatic dicar boxylic acids from alicyclic aldehydes without boxylic acid, prepared by either process, may be separating the intermediate alicyclic acid from 35 recovered by any convenient means, as by extrac the reaction mixture. tion of the acid salts with ether, acidi?cation with The aliphatic dicarboxylic acids produced ac hydrochloric acid, extraction of the acid with cording to the process of the present invention are ether, and evaporation of the ether. well known, and various methods for their prepa In carrying out the process of our invention we ration have been described. For example, have made the surprising discovery that, on con methods for the preparation of pimelic acid, a tacting an alicyclic aldehyde with a bath com- - typical dicarboxylic acid representative of those prising a. molten alkali metal hydroxide, or a mix herein contemplated which have been heretofore ture of such hydroxides, signi?cant yields of all described, include its preparation from penta cyclic alcohols are obtained. These alcohols may methylene dibromide through the cyanide proc 45 be separated from the reaction mixture,- which ess, and from trimethylene dibromide by means comprises chie?y the alkali metal carboxylate, of the malonic or acetoacetic ester synthesis. the desired alcohol, and unreacted alkali metal However, these methods are commonly suitable hydroxide, by dissolving the cooled reaction mix for laboratory scale preparation only, since the ture in, water,--acidifying with hydrochloric acid, cost of the reactants and the necessity for close 60 extracting with ether, and distlllating the ether control over the reaction conditions prevent sat extract. The acid and alcohol are separated by isfactory commercial scale operations. These the distillation. ' known processes for producing aliphatic dicar The initial reactants of the present invention‘, boxylic acids do not indicate that such acids alicyclic aldehydes, preferably have from 4 to 8 might successfully be prepared from alicyclic 55 carbon atoms in the nucleus or ring, though com-. s 2,464,047 3 4 pounds with larger rings may be used, and pref droxide baths should be operated in the lower erably the reactants have one double bond of region of the recited temperature limits. oleilnic character between two of the nuclear car In converting the alicyclic acid formed in the bon atoms, though alicyclic aldehydes with one or above-described step to the aliphatic dicarbox with two or even more such double bonds may be ylic acid, the acid and an aqueous solution of an employed and are within the scope of the present alkaline material are introduced into a vessel invention. The term "alicyclic," as used herein designed to withstand the pressure developed on with respect to aldehydes, acids and alcohols, is heating to the desired temperature, hereinafter meant to include those aldehydes, acids, and alco described. The proportions of acid, alkaline ma- hols which have a cyclic portion of aliphatic terial and water may be varied considerably, but character, and which may have one or more may advantageously be within the range of from double-bonds of ole?nic character between two about 0.5 to 2 mols of the acid, about 1.3 to 4 nuclear carbon atoms, but which excludes all mols of alkaline material and about 35 to 85 mols compounds having three conjugate double bonds of water. If the acid was not separated from the in a six membered ring, 1. e., compounds of aro 15 reaction mixture in the above-described step, the matic character. The alicyclic aldehyde react composition of the reaction mixture containing ants may be obtained from any convenient source. the alkali metal salt of the acid and free alkali For example, 3-cyclohexenecarboxaldehyde, used metal hydroxide may be adjusted usually by hereinafter to illustrate preferred embodiments adding water and, if necessary, an additional of the present invention, may be obtained by 20 quantity of an alkaline material, to bring the methods known to the art, as for example by composition substantially within the above re the addition reaction between butadiene and cited limits. In carrying out this step, we pre acrolein. fer to use an aqueous solution of an alkali metal In converting an alicyclic aldehyde to an all hydroxide. However, excellent results may be cyclic acid with simultaneous formation of an 25 achieved with aqueous solutions of other alkaline alicyclic alcohol, according to the process of our materials, such as the alkaline earth hydroxides, invention, the aldehyde is contacted with a molt e. g., barium hydroxide or ‘strontium hydroxide, en bath of any of the alkali metal hydroxides, or and aqueous solutions of salts of weal: acids and any mixture of said hydroxides, e. g., molten sodi strong bases, e. g., sodium phosphate. The reac um or potassium hydroxide, or a mixture thereof. 30 tion mixture is then heated under ambient pres We have found that molten mixtures of sodium sure, though higher or lower pressures may be and potassium hydroxides give excellent results, employed if desirable, to a temperature of from and the mixture may advantageously comprise 1 about 250° C. to about 450° C. In most instances mol of potassium hydroxide to 1/2 to 4 mols of temperatures of from about 280° C. to about 380° sodium hydroxide, which is the preferred range. C. give excellent results and are preferred. After Technical grade hydroxides may be used. since sufficient time for reaction has been allowed, we have found that the usual impurities do not usually from 2 to 10 hours, the dicarboxylic acid deleterlously a?ect the process. formed may be separated by any convenient _ In carrying out the process of our invention, we means. For example, the acid salt may be ex prefer to contact the aldehyde reactant with the tracted with ether, the ether extract acidified molten alkali metal hydroxide by passing the va with hydrochloric acid, the acid extracted with pors of the aldehyde into a bath of molten hydrox ether, and the ether evaporated. ide. However, other methods of contacting the al The products prepared according to the proc dehyde with the molten bath may be employed. ess of our invention have many uses. For ex For example, an aldehyde, and especially those 45 ample, the alicyclic acids may be treated to form aldehydes with a relatively high boiling point, esters, useful as plasticizers for various resins, may be contacted with the molten bath by intro the new alicyclic alcohols are useful as solvents, ducing the aldehyde in liquid form beneath or and form derivatives useful in detergent com upon the surface of the molten bath, in which positions, as emulsifying agents, and as driers in method the liquid may or mayinot be preheated 50 resins and varnishes, and the aliphatic dicar before contacting.