US2159700A - Process for the manufacture of unsaturated fatty acids - Google Patents

Description

Patented May 23, 1939 UNITED. STATES PROCESS FOR THE MANUFACTURE OF UN- SATURATED FATTY ACIDS Karl Hennig, Rosslau in Anhalt, Germany, as-

signor to Deutsche Hydrierwerke Aktiengesell schaft, Berlin-Charlottenburg, Germany, a corporation of Germany No Drawing. Application December 13, 1935, Se-

rial No. 54,298. In Germany December 15,

' 7 Claims. '(Cl. 260-413) a It is known to saponify spermaceti or spermaceti oil by alkalis at higher temperatures ;whereby the fatty -alcohols contained in these fatty products as constituents of the esters are converted into, fatty acids. Probably in the presence of unsaturated fat-stuffs reactions occur corresponding. to the so-called Varrentrapp reaction, i. e., the unsaturated oleic acid is decomposed to saturated palml'tic acid forming 10 the soap of this fatty acid on fusion with alkali.

Now it has been found that the action of the alkali on the mixtures of fatty alcohols occur- H ring in the oils of sea/animals or their esters, particularly the naturally occurring esters such as sperm oil or arctic sperm oil may be so conducted" that the double links existing in the raw materials are preserved by maintaining certainlimits of alkali, temperature and concentration, but particularly by applying superat- 0 mospheric pressure. In this manner unsaturated fatty acids are formed in a practically quantitative yield from unsaturated fatty alcohols and likewise from such esters which contain only unsaturated fatty acid and unsaturated fatty alcohol components. These-called Varrentrapp reaction, i. e., the formation of a saturated fatty acid from an unsaturated fatty acid under loss of two carbon atoms is entirely eliminated by avoiding excess of alkali and passing beyond certain limits of temperature. This observation is novel and renders it possibleto performflthe manufacture of. oleic acid and its homologues in a very simple way. It is only necessary to separate from the naturally occurringv mixtures of unsaturated'fatty alcohols or their esters, particularly naturally occurring esters like sperm oil or arctic sperm oil the portions which are solid in the cold by known processes from the raw materials. Often, for instance, a simple freezing out process is sufficient. The residual fluid of highly unsaturated oil is then converted into a soap in the method detailed below. Decomposition of the soap with acid yields finally an oleic-acid-like mixture of fatty acids. The

product of reaction itself, or after distilling or fractionating, is an excellent mixture of unsaturated fatty acids which may be used in the refining processes of textiles, in the production of textile assistants and in all cases in which heretofore oleic acid (so-called oleine) from tallow was applied. The conversion of the naturally occurring mixtures of fatty alcohols or their-esters, e. 5., sperm oil to fatty acids of oleic-acid-like nature is performed by first separating the solid portions of the raw materials by filtration in the cold or by other suitable processes and after addition of the necessary amount of alkali metal and alkaline earth metal hydroxides or mixtures there of by gradually heating while stirring at temperatures over 200 C. advantageously between 200 to 280 C. The alkali or earth alkali hydroxides are used preferably in a small excess previously to the reaction mixture. The end of the reaction is recognized when the evolution of the hydrogen gas stops. The formed soap is decomposed with acids. By this method a mixture of unsaturated fattyacids of the type of oleic acid is obtained which not only resembles by colour, odour and physical and chemical com The process is suitably performed unstants the oleic acid obtained by the stearin' process by pressing of! the tallow but it is also like that product which is free of highly unsaturated easy inflammable and chemically unstable higher molecular weight unsaturated acids. Therefore it is suitable not only for greasing purposesbut also for the manufacture of textile soaps and textile soap preparations, for sulfonates for emulsion purposes and so on. v

The proposed method for the manufacture of valuable oleine is a new one and provides for obtaining those products from cheap raw materials not fit for food or for the manufacture of soaps, without troublesome pressure extraction or protracted fractional distillation. Therefore it is possible to make mixtures of high molecular unsaturated fatty acids in a more satisfactory way.-

The process above may also be performed by immediately submitting without previous filtration the raw materials to the fusion with alkali and then after decomposition of the formed soap separating by filtration the solid saturated fatty acids from the fluid unsaturated fatty acids of the type of oleic acid.

Example 1 500 parts by weight of technical oleyl alcohol, (iodine number as obtained by cooling down to --15 C. and filtering in a cooled press the is distilling off. The temperature is slowly raised to 276-280 C., the quantity of hydrogen split off being a measure for the progress of the reaction. As soonas the evolutionof hydrogen is over the reaction mixture is cooled down and the formed soap is decomposed by diluted sulfuric acid. An oleic acid with the iodine number of 68-70 and a content of 9697% saponifiablefat is obtained.

Example 2 500 parts by weight of sperm oil or arctic sperm oil (iodine number 85) are.worked up in the same manner as in Example 1 with 100 parts by weight of caustic soda and 25 parts by weight of water. The solid portions of the sperm oil or arctic sperm oil are separated in the manner described in Example l. 515 parts'by weight of a mixture of unsaturated fatty acids are obtained (saponification number 202, iodine number 78-80, stock point 3). The mixture is suitable generally as a substitute for the usual oleic acid.

I claim:

1. The process for the manufacture of unsaturated fatty acids which comprises separating from sperm oil the saturated portion'which is solid at low temperatures, reacting the residual fluid portion with alkali of the group consisting of alkali metal and alkaline earth metal hydroxides in a slight excess at a temperature above 200 C. and under super-atmospheric pressure until the esters present are saponified and alkali salts of unsaturated fatty acids are formed from com-- ponents of the esters and reacting the unsaturated fatty acid salts with a mineral acid to produceunsaturated fatty acids.

2. The process for the manufacture. of unsaturated fatty acids which comprises separating from unsaturated fatty alcohol mixtures obtained from the oils of sea animals the saturated portion which is. solid at low temperatures, reacting 3. The process for the manufacture of unsat urated fatty acids which comprises separating from mixtures of esters occurring in the oils of sea animals the unsaturated esters fluid at low temperatures, reacting the same with alkali of the group consisting of alkali metal and alkaline earth metal hydroxides in a slight excess at a temperature above 200 C. and under superatmospheric pressure until the esters present are -saponified and alkali salts of unsaturated fatty acids are formed from both components of the esters and reacting the unsaturated fatty acid salts with amineral acid to produce unsaturated fatty acids.

4. The process for the manufacture of unsaturated fatty acids which comprises reacting a mixture of unsaturated fatty alcohols obtained from the oils of sea animals with alkali of the group consisting of alkali metal and alkaline earth metal hydroxides in a slight excess at a temperature between 200 and 280 C. and under a pressure of about 5 atmospheres until the same is converted to alkali salts of unsaturated fatty acids and reacting the unsaturated fatty acid salts with a mineral acid to produce unsaturated fatty acids.

5. The process for the manufacture of unsaturated fatty acids which comprises reacting a mixture of unsaturated fatty esters obtained from the oils of sea animals with alkali of the group consisting of alkali metal and alkaline earth metal hydroxides in a slight excess at a temperature, between about 200 and about 280 .C. and

under a pressure of about 5 atmospheres 'until the esters present are saponified 'and'alkali salts of unsaturated fatty acids are formed from both components of the esters and reacting the unsaturated fatty acid salts with a mineral acid to produce ,unsaturated fatty acids.

6. The process for the manufacture of unsaturated fatty acids which comprises reacting material of the group consisting of unsaturated fatty alcohols and esters of unsaturated fatty alcohols with alkali of the group consisting of alkali metal and alkaline earth metal hydroxides in a slight excess at a temperature above 200 C. and under superatmospheric pressure until the same is converted to alkali salts of unsaturated fatty acids. p

'7. The process for the manufacture of unsaturated fatty acids which comprises reacting material of the group consisting of unsaturated fatty alcohols and esters of unsaturated fatty alcohols with alkali of the group consisting of alkali metal and alkaline earth metal hydroxides in a slight excess at a temperature between about 200 and about 280 C. and under a pressure of about 5 salts ofunsaturated fatty acids.

KARL HENN'IG.

7 CERTIFICATE or CORRECTION. Patent No. 2,159,700. May- 2 1939. KARL HENNIG.

It is hereby certified that error appears in the of the above numbered patent requiring correction as fol-lows; Page 2,'f1rst column, line 10, for "276-280 0'." read 270-280 0,; line 1 0, after "from" insert the word both; and that'the said. Letters Patent should be read with this correction therein that the same may conform to the record of the easein the Pateht Office.

Signed and sealed this printed ape cification hth da of July, A, D. 1959.-

I I 4 Henry Van Arsdal'e (Seal) Acti ng Commissioner of Patents.