US2385849A

US2385849A - Esters

Info

Publication number: US2385849A
Application number: US474718A
Authority: US
Inventors: Snell Foster Dee; Albert F Guiteras
Original assignee: CHEMSEARCH CORP
Current assignee: CHEMSEARCH Corp
Priority date: 1943-02-04
Filing date: 1943-02-04
Publication date: 1945-10-02
Anticipated expiration: 1962-10-02

Description

Patented Oct. 2, 1945 ESTERS Foster Dee Snell and Albert F. Guiteras, New York, N. Y., asslgnors to Chemseareh Corporation, New York, N. Y., a corporation of New York No Drawing. Application February 4,1943,

Serial No. 474,718

18 Claims. l'Cl. 106-8) This invention relates to new organic compounds and particularly to esters of higher aliphatic alcohols and higher fatty acids having properties similar to those of certain natural waxes.

It has been understood heretofore that the natural waxes contain a large proportion of esters of unsubstituted'higher aliphatic alcohols and unsubstituted higher fatty acids. Attempts to synthesize wax substitutes by esterification of unsubstituted higher aliphatic alcohols and unsubstituted higher fatty acids' have been made heretofore. Such procedure necessarily requires alcohols and acids of very large molecular weight which are obtainable only with considerable difficulty and at great expense. Hence it has not been practicable to produce wax substitutes for commercial use by the procedure indicated.

It is the object of the invention to afford new esters which may be utilized for various industrial purposes and which are especially valuable as substitutes for natural waxes and as ingredients of wax compositions employed for polishing and other purposes.

Other objects and advantages of the invention will be apparent as it is better understood by reference to the following specification, in which the examples are set forth without limiting the invention to the particular procedure and constituents described.

We have discovered that valuable esters having commercially desirable characteristics can be prepared by esteriflcation of straight-chain saturated alcohols and straightehain monocarboxylic fatty acids in which either the alcohol or the acid has a hydrogen replaced by one and not more than one hydroxy group, both the alcohol and the acid represented in the ester containing substantially not less than 16 nor more than 24 carbon atoms. Such esters are monohydroxy esters of the alcohols and acids as defined.

These esters have relatively high melting points, are hard at ordinary temperatures, susceptible of application to give a high polish and therefore suitable for use as a polishing wax as well as for other purposes where the esters can replace waxes of natural origin. Numerous possible uses of the esters other than as polishing materials will occur.

It was to have been expected that monohydroxy esters of the kind described would have properties approximating those of corresponding non-hydroxy and dihydroxy esters. It has been found, however, that the monohydroxy esters have quite different characteristics. Thus, the

new ester, octadecyl monohydroxystearate, prepared according to the invention, is hard at ordinary atmospheric temperatures. When used as a polishing wax, it gives a good gloss, and it can be used in substantial amounts in commercial self-polishing wax compositions.

Octadecyl dihydroxystearate on the other hand has a soft and greasy feel. Likewise, octadecyl stearate containing no hydroxy group is soft to the touch. Neither is suitable for use as a substitute for the products of the present invention. Both octadecyl stearate and octadecyl dihydroxystearate when made into a gel of 50% concentration with mineral oil show bleeding out of the solvent on standing, whereas the gel with the new ester octadecyl monohydroxystearate shows no bleeding under similar conditions. Compatibility with mineral oil is essential to a wax which is to ed, containing approximately 16 to 24 carbon atoms to the molecule. Examples of acids which are suitable are the monohydroxy derivatives of palmitic, stearic, arachidic and behenic acids. More specifically we may use to advantage alphahydroxy palmitic acid, CH3(CH2)13CHOHCOOH, alpha-hydroxy stearic acid CH3 (CH2) 15CHOHCOOH alpha-hydroxy arachidic acid ormcm) ncnorrcoon and 12-hydroxy stearic acid CH3 (CH2) 5CHOH(CH2) ioCOOH the latter being particularly suitable in forming esters with 016-024 alcohols which are excellent waxes. The acids referred to may be considered as hydroxy-soap-forming acids.

As the alcohol to be esterifled with such acids,

we select one which is a straight chain saturated and preferably primary alcohol containing not substantially less than 16 nor more than 24 carbon atoms to the molecule, as for example hexadecyl, CH3(CH2)14CH2OH, heptadecyl CH3 (CH2) 15CH2OH and octadecyl CH3(CH2)16CH2OH alcohols. It appears that the orientation of the structure is interfered with by branching of the chain. Thus, a product of a branch chain acid or secondary alcohol is inferior to that 'of a straight chain acid or primary alcohol.

When the hydroxy group of the finished ester is to be supplied by the alcohol, the acid selected should be an unsubstituted fatty acid containing about 16 to 24 carbon atoms, as for example palmitic, cI-mcrn) 14COOH, oleic or stearic acid crmcmmcoon. The acid is esterifled with a diol containing approximately 16 to 24 carbon atoms, preferably having the -OH groups on the end carbons of a straight chain molecule. Examples of diols which may be used are 1,12-octadecane diol CH1(CH:) sCHOH(CI-I2) mCHrOH 1,16-hexadecane diol, CHzOH( CHr)14CH2OH. and 1,18-octadecane diol, cmomcmmcrnon.

We prefer to use a hydroxy soap-forming acid and a non-substituted alcohol such as octadecanol CH3(CI-I2)1sCI-I2OH rather than an unsubstituted acid and a diol. If diols are used, isomers may be formed, and unless the hydroxyls are on the terminal carbons, branching results in some of the molecules. The product may be used for many purposes, although not quite so satisfactory as one produced by esterification of monohyclroxyacid with a non-substituted alco- Whether the substituted hydroxy group is initially present in the acid or in the alcohol, the esterification is eil'ected by combining the selected acids and alcohols with the aid of a suitable catalyst in the proportions of substantially mol for mol. The preferred catalyst is p-toluene sulfonic acid, but other catalysts may be employed, as for example sulphuric or hydrochloric acid. The latter catalysts are not quite so satisfactory as the p-toluene sulfonic acid.

In preparing the ester, the selected higher alcohol and the higher fatty acid are mixed in a melted condition. The esterification is effected under conditions that promote reaction and preferably also remove, by volatilization, water formed in the reaction. Suitably the mixture of alcohol and acid in approximately equi-molecular proportions is mixed with a small proportion, say 0.05% to 1%, of the esteriflcation catalyst. The mixture is heated so that esterification proceeds relatively rapidly and preferably to a temperature somewhat above the boiling point of water, the water formed as a byproduct of esterification being removed from the sphere of the reaction by volatilization.

Removal of water may be facilitated by vacuum or passage of an inert gas through the mixture. Nitrogen may be used as the inert gas and improves the color by reducing air exposure. It also reduces the final acid value. The temperature should at all times be kept below that at which progressive darkening or decomposition of the alcohol, acid and resulting ester occur to an objectionable extent.

When tests show that the acid is substantially completely esterifled, the heating is discontinued and the product is suitably cooled to a tempera-' ture slightly above the melting point. The product may then be treated in any'conventional manner for removing the acid catalyst from the water insoluble ester. It may, for'example, be washed with several portions of water to remove the acid catalyst, or there may be added and stirred into the molten mass a small proportion assasco of a neutralizing agent for the catalyst as for example finely divided calcium carbonate, anhydrous sodium or potassium acetate. or ammonia. strictly necessary in many cases. v

The invention will be further illustrated by the following specific examples:

As a typical case, 12-hydroxy stearic acid is first obtained from anysuitable source. It may be made by hydrogenating castor oil, saponifying the hydrogenated product, acidifying the soap so produced, and then separating the fatty acid from water soluble substances present, all in a conventional manner. The fatty acid so made consists largely of 12-hydroxy stearlc acid and is sufficiently pure for the purpose of the invention.

The 12-hydroxy stearic acid prepared as described or in any other manner is melted in a steam-jacketed kettle with octadecyl alcohol. The alcohol and acid are used in approximately equal weights, as for example, 144 parts by weight of monohydroxy stearic acid to 130 parts of octadecyl alcohol. The catalyst consisting of one part by weight of p-toluene sulfonic acid of the 74%-75% commercial grade is added. The whole is stirred with a slow mechanical agitator and maintained at a temperature of about nil- C. for approximately 2 to 4 hours.

Tests made during the heating of the batch show that the acid value drops to about 4.8 and the melting point of the product rises gradually and then becomes practically constant. The catalyst may be removed by washing or it may be neutralized. The product is then allowed to cool partly and is cast in suitable receivers such as metal molds. There is thus obtained a yield of 241 parts, consisting largely of octadecyl 12- hydroxy stearate CH3(CH2) sCHOH(CHa) 1oC'OOCH2iCI-I2) CH:

having a melting point of approximately 71 C. When re-crystallized from warm alcohol, we obtain purified octadecyl monohydroxystearate melting at approximately 73 C.

Other esters are made by substituting other alcohols and other fatty acids of the class described mol for mol for the octadecyl alcohol and monohydroxy stearic acid respectively in .the above example. Provided the alcohols and acids are selected as described, the esters have properties similar to the ester obtained in accordance with the example. 7

Following the same procedure as in the preceding example, we can produce esters of non-hydroxy monocarboxylic fatty acids with diols. Thus the ester of stearic acid with 1,12 -octadecane diol is obtained by esterifying these compounds under the conditions described. This ester is 12-hydroxy octadecyl stearate CH3 (CH2) 1sCOOCHa(CI-I2) 10CHOH(CH2) sCH:

Other non-hydroxy acids of the same class may be combined with other diols to produce commercially valuable esters. The esters have characteristics similar to those resultin from the practice of the procedure in which hydroxy acids are combined with monohydric alcohols. The polishing characteristics are not quite so good, but the esters are suitable for many purposes.

When the alkyl monohydroxy acid ester is to be used in a polish dispersed in water, the ester is preferably blended with carnauba wax or other natural materials and those minor ingredients 'which are conventional in water dispersible wax polishes. The proportions of carnauba wax Removal of the acid catalyst is not assasca intention to limit the invention to such specific examples.

We claim:

1. A monohydroxy ester of a straight chain saturated monocarboxylic fatty acid and a straight chain saturated alkyl monohydroxy alcohol, each containing not less than 16 nor more than 24 carbon atoms to the molecule.

2. A monohydroxy ester of a straight chain saturated monocarboxylic fatty acid and a straight chain saturated alkyl alcohol, each containing not less than 16 nor more than 24 carbon atoms to the molecule, in which the hydroxy group occurs in the acid portion of the ester.

3. A monohydroxy ester of a straight chain saturated monocarboxylic fatty acid and a straight chain saturated alkyl alcohol, each containing not less than 16.nor more than 24 carbon atoms to the molecule, in which the hydroxy group occurs in the alcohol portion of the ester.

4. A monohydroxy ester of l2-hydroxystearic acid with a straight chain saturated allwl alcohol containing approximately 16 to 24 carbon atoms to the molecule.

5.-A monohydroxy monoester of octadecane diol with a straight chain saturated fatty acid containing approximately 16 to 24 carbon atoms to the molecule.

6. Octadecyl 12-hydroxystearate CH3(CH2) sCHOH(CH2) 10COOCH2(CH2) 1sCHa 7. l2-hydroxyoctadecyl stearate CH3 (CH2) 1sCOOCHz(CH:)1oCI-IOH(CH2)sCI-Ia 8. A polishing composition comprising an intimate blend of the synthetic wax described in claim 1 and carnauba wax, the carnauba wax increasing the dispersibility of the synthetic wax in water.

9. A polishing composition comprising an intimate blend of the synthetic wax described in claim 1 and a natural wax, the natural wax increasing the dispersibility oi the synthetic wax in water.

10. A saturated monohydroxy monoester con-- sisting of the reaction product of equimolecular amounts of a saturated straight chain monocarboxylic fatty acid and a saturated straight chain alkyl alcohol, each containing not less than 16 nor more than 24 carbon atoms to the molecule.

11. The method of producing monohydroxy esters in which the hydroxy group occurs in the acid portion of the ester which comprises reacting a straight chain saturated monohydroxy ters in which the hydroxy group occurs in the acid portion of the ester which comprises reacting a straight chain saturated monohydroxy monocarboxylic acid containing not less than 16 nor more than 24 carbon atoms to the molecule with a substantially equimolecular amount of a straight chain saturated alkyl monohydroxy alcohol containing not less than 16 nor more than 24 carbon atoms, and maintaining the mixture at a temperature above the boiling point of water at the existing pressure during esteriilcation, so that water formed as a by-product of the esteriilcation is removed.

13. The method or producing monohydroxy esters in which the hydroxy group occurs in the acid portion of the ester which comprises reacting a straight chain saturated monohydroxy monocarboxylic acid containing not less than 16 nor more than 24' carbon atoms to the molecule with a straight chain saturated alkyl monohydroxy alcohol containing not less than 16 nor more than 24 carbon atoms, andmaintaining the mixture, in the presence of an esteriflcation catalyst, at a temperature above the boiling point of water at the existing pressure during esteriilcation, so that water formed as a by-product of the esteriflcation is removed.

14. The method of producing monohydroxy esters in which the hydroxy group occurs in the acid portion of the ester which comprises reacting a straight chain saturated monohydroxy monocarboxylic acid containing not less than 16 nor more than 24 carbon atoms to the molecule with a straight chain saturated alkyl monohydroxy alcohol containing not less than 16 nor more than 24 carbon atoms, maintaining the mixture at an elevated temperature until esterification has taken place, and removing water formed as a by-product of the reaction by blowing through the resulting ester 9. gas inert thereto.

15. The method of producing monohydroxy esters in which the hydroxy group occurs in the acid portion of the ester which comprises reacting a straight chain saturated monohydroxy monocarboxylic acid containing not less than 16 nor more than 24 carbon atoms to the molecule with a straight chain saturated alkyl monohydroxy alcohol containing not less than 16 nor more than 24 carbon atoms, in the presence of an esteriflcation catalyst, and removing water formed as a by-product of the reaction by blowing through the resulting ester 2. gas inert thereto.

16. The method of producing monohydroxy esters in which the hydroxy group occurs in the acid portion of the ester which comprises reacting a straight chain saturated monohydroxy monocarboxylic acid containing not less than 16 nor more than 24 carbon atoms to the molecule with a substantially equimolecular amount of a straight chain saturated alkyl monohydroxy alcohol containing not less than 16 nor more than 24 carbon atoms, in the presence 01' an esteriflcation catalyst, and removing wateriormed as a by-product of the reaction by blowing through the resulting ester a gas inert thereto.

17. The method of producing monohydroxy esters in which the hydroxy group occurs in the alcohol portion of the ester which comprises reacting a non-substituted straight chain saturated monocarboxylic acid containing not less than 16 nor more than 24 carbon atoms to the molecule with a saturated straight chain alkyl diol containing not less than 16 nor more than 24 carbon atoms to the molecule, and removing water formed as a by-product during the esterification by blowing throughthe ester a gas which is inert thereto.

18. The method of producing monohydroxy esters in which the hydroxy group occurs in the alcohol portion of the ester which comprises reacting a non-substituted straight chain saturated monocarboxylic acid containing not less than 16 nor more than 24 carbon atoms to the molecule m water at the existing pressure during esterification, so that water formed as a by-product of the esterification is removed.

FOSTER DEE SNELL. ALBERT F. GUITERAS.