US1786248A - Production of neutral fats and oils - Google Patents

Description

Patented Dec. 23, 1930 UNITED STATES,

OTTO JORDAN, OF LUDWIGSHAFEN-ON-THE-RHINE, AND GEORG KRAEMER, 0F HEIDEL- BERG, GERMANY, ASSIGNORS TO I. G. FARBENINDUSTRIE AKTIENGESELLSCHAFT, OF FRANKFORT-ON-THE-MAIN, GERMANY, A CORPORATION OF GERMANY rnonucm'ron or NEITTRAL rams ANn'oILs Ho Drawing. Application filed March 18, 1929, Serial No. 348,122, and in Germany April 5, 1928.

pletely neutral condition, these free fatty acids are usually removed by'treat-ment with alkaline agents or by means of special distillation processes. It has also been proposed to convert the free fatty acids present in fats or oils into neutral compounds, by esterification with glycerol or glycol. .All these processes, however, are attended with various objections such as loss of oil, decomposition phenomena due to overheating and the like.

We have now found that neutral fats and oils can be obtained, ina simple manner, from fats and oils containing free fatty acids, such as castor oil, linseed oil, peanut or soj a bean' oil, by'a treatment thereof with an alkylene oxide, which term comprises ethylene oxide and its homologues such as propylene oxide and the like, preferably in the warm, and, advantageously, with the employment of catalysts. Such catalysts are for example metal acetates, phosphates or chlorides, preferably these salts of alkaline metals and alkaline earth metals, metal oxides such as alumina or titanium dioxide, weak acids or even small amounts of water. Working with acids as catalysts is however a little diflicult, since these might tend to split the esters when the reaction temperature is a little too high. The aforesaid solid catalysts can also be employed when deposited on carriers. The process has the advantage that the reaction of the ethylene oxide or the like with the fatty acids takes place at even moderate temperatures and that complete esterification can be carried out at substantially lower temperatures than in the case of the esterification methods hitherto employed so that no destructive decomposition of the initial materials occurs. The process can be carried out also at a pressure above atmospheric pressure and accelerated thereby, which increased pressures can be attained for example by working in a closed vessel and at a temperature above the boiling point of the catalyst, when the period of time required for the reaction should not be unduly long. The pressure within the reaction vessel can also be increased by introducing gases, for example carbon dioxide and the like, in the usual manner. The temperature employed should generally be above the boiling point of the alkylene oxide employed, a tempera ture between about 100 and 200 being usually most efficient and being chosen depending on the nature of the catalyst employed. The resulting products are presumably hydroxyalkyl esters of the fatty acids, the free hydroxyl groups of which can be still further esterified in any known manner. The reactions can be illustrated by the following equations:

aooonq-cm-om-mcoocu,crnon and The following examples will further illustrate the nature of the invention which however is not restricted thereto. The parts are by weight. I

Example 1 temperature) for four hours in a suitable pressure tight vessel, the mixture being kept in motion. The unaltered ethylene oxide is then-distilled off. The residual oil, which is not deepened in color, has then an acid value a of 0.084 only.

The operation may also be conducted at still lower temperatures, for example at water-bath temperature, but in such cases longer heating is advisable in ordertto obtain completeesterification.

If linseed oil be replaced by other oils or fats containin free fatty acids, of high molecular weig t, a similarly favorable neutralization of the fatty acids is obtained.

Emapz-ple 2 In a tower which is provided with a heating device and filled with Raschig rings consisting of stone ware, porcelain or iron, linseed oil is circulated after heating the oil to from 160 to 170 centigrade, while ethylene oxide is simultaneously introduced at the bottom of the tower. The ethylene oxide which has not been consumed in its passage flows out at the top of the tower and is utilized a ain until the oil is completely neutral, w ich effect is attained in about 6 hours. If desired, the reaction can be performed in a series of towers, the ethylene oxide eifiuing from one tower bein then preferably introduced at the bottom 0% one of the other towers.

The process can be applied also to other oils than linseed oil and the Raschig rings can be replaced by other solid bodies with a large superficial area for example by small lumps of pumice or clay. The said solid bodies can be impregnated with a catalyst or the catalyst may be shaped to solid granules or to other bodies possessing preferably a large superficial area. Example 3 parts of soja bean oil with an acid value 0 3.7 are heated in a pressure-tight vessel with 20 parts of ethylene oxide at about from 160 to 170 centigrade for about from 3 to 4 hours. The ethylene oxide not consumed is then distilled off and the slimes contained in the oil are separated by centrifuging. The acid value of the product is 0.05 only.

Example 4 1500 parts of peanut oil with an acid value of 10.4 are stirred in a pressure-tight vessel together with 30 parts of ethylene oxide and 10 parts of anhydrous sodium acetate at about 100 ccntigrade and for from 5 to 6 hours. The remainders of'ethylene oxide are then distilled off and the sodium acetate and the slimes are separated by centrifuging. The oil obtained possesses an acid value of 0.06 only.

Example 5 E mample 6 2000 parts of linseeZ oil with an acid value of 21.4 are stirred 01 8 hours in a pressuretight vessel together with 60 parts of propylene oxide at about from 170 to 180 centigrade. After the said period of time the remaining propylene oxide is distilled off. After removal of the-slimes by centrifuging the oil obtained possesses an acid value of 006.

Example '7 300 parts of a castor oil, miscible with mineral oil and possessing an acid value of 9.3, are heated in a pressure-tight vessel with 20 parts of ethylene oxide and 5 parts of pulverized titanium dioxide for 8 hours at a temperature of 120 to 125 Centigrade. The remaining ethylene oxide is then distilled off and the oil is stirred, while warming, with a little animal charcoal and calcined bleaching earth and then filtered. The oil obtained has practically no acid value and a higher resistance to oxidizing influences than the initial material.

Instead of the modified castor oil miscible with mineral oil, which modified castor oil can be obtained by subjecting castor oil to a distillation while gradually increasing the temperature to 300 C. and keeping the content of the still at the said temperature for from 1 to 2 hours until from 10 to 12 per cent by weight have been distilled off, common castor oil can be employed and the titanium dioxide can be replaced by other metal oxides, for example by alumina, or by metal chloride, sodium chloride and the like.

Epample 8 1000 arts of linseed oil with an acid value 0 141 are treated with 160 parts of ethylene oxide in the manner described in Example 1. The product obtained is then heated with 250 parts of acetic anhydride to a temperature of 120 to 130 centigrade for 4 hours whereupon the remainders of the anhydride and the acetic acid formed are distilled off in vacuo. The neutral oil is thus converted into the acetic esters of the hydroxy ethyl esters of the acids contained in the original linseed oil. The reaction can be illustrated by "the following equation, RCOOH denoting the free linoleic acid:

What we claim is 1. The process for the production of neutral fats and oils which comprises acting with an alkylene oxide on a material selected from the group of fats and oils containing free acids.

2. The process for the prodution of neutral fats and oils which comprises acting with an alkylene oxide on a material selected rom the group of fats and oils containing free acids, at a temperature above the boiling point of the alkylene oxide employed.

3. The process for the production of neutral fats and oils which with an alkylene oxide on a material selected from the group of fats and oils containing free acids, at a temperature-between about 100 and 200 Centigrade.

4 The process for the tral fats and oils which comprises acting with an alkylene oxide on a material selected from the group of fats and oils containing free acids, at a temperature above the boiling point of the alkylene oxide employed and in the presence of a catalyst.

5. The process for the production of neutral fats and oils which comprises acting with an alkylene oxide on a Vegetable oil containing free acids, at a temperature above the boiling point of the alkylene oxide employed. v I

6. The process for the production of neutral fats and oilswhich comprises acting with an alkylene oxide on a vegetable'oil containing free acids, the boiling ployed and point of the alkylene oxide em in the presence of a-catalyst. e process for the production of neutral fats and oils which comprises acting with ethylene oxide on a vegetable oil containing free acids, ata temperature between about 100 and 200 centigrade;

8. The process for the production of neutral fats andoils which comprises acting with ethyleneoxide on linseed oil containing free acids at a-temperature between about 100 and 200 centigrade.

9. The process for the productionv of neurol fats and oils which comprises acting with ethylene oxide on linseed'oil containing free acids, at a temperature vbetween about 100 and 200 centigrade and in the presence of a catalyst."

In testimony whereof we have hereunto set our hands.

' OTTO JORDAN.

GEORG KRAEMER.

comprises acting.

productic n of neuat a temperature above