US2157144A - Diesters of unsaturated glycols and processes of preparing the same - Google Patents

Description

Patented May 9, 1939 UNITED STATES PATENT OFFICE DIESTERS OF UNSATURATED GLYCOLS AND PROCESSES OF PREPARING THE SAME No Drawing. Application November 22, 1937, Serial No. 175,978

8 Claims.

This invention relates to diesters of unsaturated glycols and processes of preparing the same, and it comprises as new materials substances having the general formula wherein R is an alkyl group having from eleven to seventeen carbon atoms, and it further comprises processes wherein fatty acid chlorides corresponding to fatty acids having from twelve to eighteen carbon atoms are reacted with an alkali metal, such as sodium or potassium, for the preparation of such esters.

The fatty acid chlorides, namely those materials having the structural formula RCOCl can be. prepared from fatty acids by the action of thionyl chloride, phosphorous trichloride, or phosphorous pentachloride. The fatty acids themselves are extremely abundant and relative- 1y inexpensive, and because of the ease with which these acids can be converted to acid chloride, and the reactivity of the acid chlorides, the fatty acids are important starting materials for the preparation of many organic compounds. The fatty acid chlorides are extremely reactive with alcohols to form esters, and are important reagents in the preparation of materials by a Friedel-Crafts synthesis.

We have now discovered that the fatty acid chlorides having from twelve to eighteen. carbon atoms react smoothly with alkali metals, such as sodium or potassium, to give diesters of unsaturated glycols. The reaction is probably as follows:

When the starting chloride is one containing twelve to eighteen carbon atoms the diesters obtained are wax-like materials useful in a number of fields, for example, as dielectrics and in waxing and polishing compositions.

Broadly speaking then, our invention comprises reacting fatty acid chlorides having from twelve to eighteen carbon atoms with alkali metals, namely sodium or potassium, under conditions, as hereinafter specified, leading to the formation of diesters of unsaturated glycols.

As starting materials we can use substantially pure fatty acid chlorides having twelve or more carbon atoms, or we can use mixtures of fatty acid chlorides. For example, we can start with lauryl chloride and obtain as a final product the dilaurate of tetracosene-12,diol-12,13. Or we can start with mixtures of different fatty acid chlorides and obtain mixed esters of the charac ter specified. Consequently, in the appended claims we define our materials by reference to their structural formula and denote the alkyl groups of said formula as having from eleven to seventeen carbon atoms.

We shall now give examples of how our inventionmay be practised.

Example 1 13.8 grams of sodium ribbon and 500 cc. of anhydrous ether or other inert solvent are placed in a three-necked flask equipped with a motor stirrer, reflux condenser and dropping funnel. 109 grams of lauryl chloride, prepared by the action of thionyl chloride and lauric acid, are dissolved in cc. of anhydrous ether or other inert solvent. This solution is then added dropwise to the flask containing the ether and sodium over a period of three and one-half hours. A vigorous reaction takes place which is easily controlled by the rate of addition of the lauryl chloride solution. After the addition of the lauryl chloride the reaction mixture is refluxed for about two hours. The mixture is then filtered from the sodium chloride and excess sodium and the ether removed by distillation, the last traces being removed under an absolute pressure of 20 mm. of mercury. The product is a light-colored, waxy solid. After recrystallization from an acetone-benzene mixture or other solvent, 80.5 grams of product are obtained. On further recrystallization to a constant melting point from acetone-benzene 62.5 grams of final product are obtained having a melting point of 423 C. The product is the dilaurate of tetracosene-l2,diol- 12,13. The proof of the composition of this compound follows:

In order to further prove the structure of this compound we can saponify it with alcoholic KOI-I to lauroin and lauric acid. The lauroin obtained has a melting point of 62 3.5 C. These results show that the diester we obtain is:

I 011 2: C u aa Example 2 Example 3 61 grams of stearyl chloride are dissolved in '75 cc. of anhydrous ethyl ether and the solution added to 6.7 grams of sodium wire suspended in 200 cc. of anhydrous ethyl ether over one hour, after which the reaction mixture is refluxed twenty-one hours. The product is then treated as described under Example 1. After eight crystallization 31 grams of the distearate of hexatriacontene-18,diol-18,19 are obtained having a melting point of 6768 C. and a saponification number of 109. Saponification with alcoholic KOH gives stearoin, melting point '78-80 C.

Having thus described our invention, what we claim is:

1. A diester having the structural formula wherein the R groups are alkyl radicals having eleven to seventeen carbon atoms.

2. The dilaurate of tetracosene-12,diol-12,13.

3. The dimyristate of octacosene-14,diol-14,15.

4. The distearate of hexatriacontene-18,dio1- 18,19.

5. The process of preparing diesters of unsaturated glycols which comprises reacting a fatty acid chloride having twelve to eighteen carbon atoms with an alkali metal while in an inert solvent for the fatty acid chloride.

6. The process of preparing diesters of unsaturated glycols which comprises reacting an ether solution of a fatty acid chloride having twelve to eighteen carbon atoms with an alkali metal.

7. The process as in claim 5 wherein the metal is sodium.

8. The process as in claim 6 wherein the metal is sodium.

ANDERSON W. RALSTON. WILLIAM M. SELBY.