US2340688A - Process of forming alcohols - Google Patents

Description

Patented Feb. 1, 1944 raocass or roams ALCOHOLS Albert S. Richardson, Wyoming, and James E.

Taylor, Cincinnati, Ohio,

assignors to The Procter and Gamble Company, Ivorydale, Ohio, 7 a corporation of Ohio No Drawing. Application April 13, I942,

- Serial No; 438.853

7 Claims. (Cl- 260-638) Our invention relates to a process for forming alcohols by reacting hydrogen with certain metallic salts of carboxylic acids.

'The present application is a continuation-inpart of our applications-Sen Nos. 380,072 and 380,073, both filed February 21, 1941. The first of these disclosed a general process for forming alcohols and esters by hydrogenating the corresponding carboiqrlates of certain metals at high temperature and pressure; and the second disclosed a similar process directed specifically to forming unsaturated alcohols and esters from corresponding unsaturated carboxylates of certain metals. 7

Among the carboxylates which respond to the processes of the above mentioned applications are carboxylates of each of several specific metals which give relatively good yields of free and combined alcohol when Hydrogenated in the absence of other free or combined metals, among the reactants. When subjected to reaction with hydrogen under the conditions of our general process, soaps of these metals, for example, are converted to alcohols and esters corresponding to the fatty acid radicals of these soaps, with liberation of the free metal and water:

If the B group of the carboxylate contains one or more double carbon bonds,

the alcohol and ester products will for the most part also contain these linkages.

Soaps of chromium hydrogenated by themselves according to our process give only moderate yields'of free and combined alcohol, and soaps of zinc hydrogenated by themselves give even lower yields of these products.

The subject matter and claims of the present application are based upon our discovery that when mixtures of soaps of chromium and of zinc are hydrogenated the yield of total alcohol obtained is much higher than when soaps of either of these metals are similarly hydrogenated by themselves. Furthermore we have found that if the fatty acid radicals of the soaps are unsaturated the resulting alcohols also tend to be imsaturated.

Thus our present process provides an improved means of forming higher alcohols, which may contain unsaturated carbon-carbon linkages if the starting materials are unsaturated. 'Such a process, which is not dependent. upon added .metailic or metal oxide catalysts, has advantages over previously described methods of makingoleic acid," and the alcohols resulting from the process are referred to as oleyl alcohol.

The extent of the reduction of the carboiwl group is calculated from the saponiflcation value of the original oleic acid and the saponiflcation value of the acid washed, water washed, and dried reaction product. The per cent total alcohol in the acid washed (and water washed and dried) product is determined either by calculation from the hydroxyl value determined on the unsaponiflable matter in the acid washed product, or by calculation from the acid value, saponification value, and hydroxyl value of the acid washed product. In either case the per cent total alcohol-includes both' free oleyl alcohol and oleyl alcohol combined as ester, the latter being liberated when the acid washed product is saponified.

Ezample.zinc oleate and chromium oleate were separately prepared by treating solutions of "red oil sodium soaps with solutions of zinc nitrate and with chromium sulfate, respectively, and washing and drying the precipitated metallic soaps. A mixture of grams of this zinc oleate and 50 grams of this chromium oleate was placed in the reaction bomb at room temperature, air

was displaced from this vessel by admitting hydrogen and venting the bomb, and then hydro.- gen was introduced to build up the pressure in the bomb to about 1800 pounds per square inch. The bomb was sealed and heated to about 340 C. The contents were agitated by rocking the bomb, while maintaining a pressure of 3500 pounds per square inch by adding more hydrogen when necessary, for three hours. allowed to cool to a temperature convenient for handling, excess gas pressure was released, and the non-gaseous organic contents were removed, boiled with a 10% aqueous solution of hydrochloric or other suitable mineral acid, water The bombwas then washed until free from mineral acid, and dried.

'lhls acid washed product was found to contain slightly over 35% of free and combined oleyl alcohol having an iodine value of 64.

ditlons suiiicient for the attainment of substantial completion of the reaction.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

Free alcohol was obtained from the acid washed 1, In a process for forming alcohols, the step material by reacting fatty acids and esters in m h cqnsists essentially in subjecting t this material with caustic alkali, extracting with tion, with hydrogen 9, mixture of salts of carboxether, and distll lin K h s Solvent- The p ylic acids corresponding to said alcohols, said O Separating t free 0 0 f q the alkali mixture of salts comprising essentially carboxsoap m y l ernate y be mp i h d y ms ylates of zinc and chromium, the reaction temtillation 1 y y other convemellt methodperature and hydrogen pressure being suilicient- The following table contains further data con- 1y above atmospheric to effect substantial reduccerning the above example, together with corretion of the carboxylic group C0O-- of'said sponding data for oleates of each of the two salts to the group -CH2O of said alcohols. metals when hydrogenated alone. 2. In a process for forming alcohols, the step Process conditions Results llcgrboxylgetgs I t er gggg Pressure Time et; may, 1. vs on 0, Pounds Hours 100% Croleate 340 3,500 a so 27 101 352523;: 3 i l ,Znoleate..- 340 3,500 3 as 2 1o 1 Per cent reduction of carboxyl grou I Per cent total alcohol, free and combined, in acid washed product Iodine value 0! acid washed product or of unsaponiilable matter (including total 4 alcohol) obtained therefrom.

Our process as exemplified by the above spewhich consistsessentially in subjecting to reaction with hydrogen a mixture of soaps of fatty ciilc applicationis equally applicable to treatment of soaps of all fatty acids occurring in natural vegetable, animal, and marine fats and oils. Thus carboxylates of our preferred metals and fatty-acids derived from coconut oil, tallow, vegetable oils, fish oils,'hydrogenated oils, etc, may be treated to produce the corresponding fatty alcohols. Similarly, our process is applicable to hydrogenation of mixtures of chromium and zinc salts of carboxylic acids generally, a1-

' though we do not claim that it is equally eflicient as applied to conversion of all such salts to alcohols. It is well known, of course, that carboxylic acids and their derivatives diil'er in thermal stability and the outstanding merit of our process as applied to production of the higher alcohols is due in large part to the resistance of the salts of the fatty acids to decomposition by side reactions under the conditions employed in our process.

It will be appreciated that the advantages of the instant invention may be achieved in increasin: degree by the use of greater amounts of carboxylates of the preferred metals set forth heresome form of agitation to promote intimate contact between the hydrogen and the reacting carboxylates, the maintenance of a constant supply of hydrogen, andtime under these reaction conacids corresponding to said alcohols, said mixture of soaps comprising essentially soaps of zinc and chromium. the reaction temperature and hydrogen pressure being sufliciently above atmosplnric to effect substantial reduction of the carboxylic group CO0 of said. soaps to the (foul -CHz-O-'- of said alcohols.

'3. The process of forming higher alcohols, which comprises subjecting to reaction with hydrogen, at a temperature between about 240 and 400 C. and at a hydrogen presssure above 2000 pounds per square inch, soaps of fatty acids corresponding to said alcohols, said mixture of soaps comprising essentially soaps of zinc and of chromium.

4. The process of claim 3, in which the soaps are soaps of unsaturated fatty acids, whereby the alcohols formed are for the most part unsaturated alcohols.

5. The process of claim 3, in which the soaps,

are soaps of oleic acid.

6. The process of claim 3, in which the soaps are soaps of coconut oil mixed fatty acids.

7. The process of forming higher alcohols which comprises: subjecting to reaction with hydrogen, at a temperature between about 240 and 400 C. and at a hydrogen pressure above 2000 pounds per square inch, a mixture of soaps of fatty acids corresponding to said alcohols, said mixture of soaps comprising essentially soaps of