US2426902A - Higher alkyl esters of chloromaleic acid - Google Patents

Description

Patented Sept. 2, 1947 UNITED STATES PATENT OFFICE f HIGHER ALKYL ESTERS OF CHLORO- MALEIC ACID Raymond B. Seymour, Dayton, Ohio, a'ssignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing.

This invention relates to esters of chloromaleic acid and alcohols having at least 8 carbon atoms and to methods of producing the same.

An object of the present invention is to provide I new and useful esters of chloromaleic acid. An-

other object of the invention is to provide new v COOY wherein A signifies the group CH:CC1, X stands for an alkyl group of at least 8 carbon atoms and Y is either the same as X or standsfor an aralkyl group of from 7 to 9 carbon atoms, an alkoxy-substituted alkyl group of from 3 to carbon atoms, a chlorine substituted alkyl group of from 2 to 4 carbon atoms, an alkyl group of- -from 1 to 7 carbon atoms, or hydrogen.

As examples of chloromaleates having the above general formula may be mentioned dioctyl chloromaleate, mono-octyl 2-chloromaleate,

'mono-octyl l-chloromaleate, bis(2-ethylhexyl) chloromaleate, mono-'(Z-ethylhexyl) 2-chloromaleate, bisU-methylheptyl) maleate, mono-(1- methylheptyl) 2-chloromaleate, mono-decyl 1- chloromaleate, mono-undecyl 2-chloromaleate, diundecyl chloromaleate, mono-dodecyl l-chloromaleate, mono-hexadecyl 2-chloromaleate, di-

hexadecyl chloromaleate, dioctadecyl chloromaleate, 2-ethylhexy1 alpha-chloro-beta-carbomethoxyacrylate, octadecyl beta-chloro-beta-carbobutoxyacrylate, dodecyl beta-chloro-beta-carbobenzyloxyacrylate, undecyl alpha-chloro-beta- (carbo-beta-phenylethoxy) acrylate, beta-chlorm ethyl alpha-chloro-betacarbodecyloxyacrylate,

. gamma-chloro-propyl beta-chloro-beta-carbododecyloxyacrylate, beta-ethoxyethyl alpha-chlorobeta carbo 2 ethylhexyl) oxyacrylate, gammabutoxypropyl beta-chloro-beta-carbohexadecyloxyacrylate, etc.

Application November 10, 1943, Serial No. 509,768

2 Claims. (01. 260-485) As alcohols which may be employed'for preparation of esters of chloromaleic acid containing at least one esterifying group derived from an alcohol of at least 8 carbon atoms may be mentioned n-octanol, iso-octanol, 2-eth ylhexanol, nonyl alcohol,decyl alcohol, undecyl alcohol, lauryl alcohol, pentadecanol, cetyl alcohol, octadecyl alcohol, etc. Particularly useful are mixtures of higher alcohols obtained, for example, by hydrogenation of such commercially available fatty acids as laurlc acid (the commercial product known as "Lorol), stearic acid or oleic acid or the mixtures'of higher acids obtainable by oxidation of petroleum fractions. In general such alcohols should contain between 8 and 18 carbon atoms.

By employing for esterification a mixture of alcohols, said mixture containing at least one of the higher alcohols selected from the above list, mixed esters of an improved type and unusual properties may be obtained. Suitable mixtures may consist of substantially equal molar quantities of two of the above-mentioned higher alcohols or a mixture of molar quantities of one of said higher alcohols and another alcohol selected from the group consisting of aliphatic alcohols of from 1 to 8 carbon atoms, aralkylalcohols of from '7 to 9 carbon atoms, alkoxy-substituted alcohols of from 3 to 10 carbon atoms and chlorosubstituted alcohols of 2 to 4 carbon atoms. As examples of alcohols which may be used with the present higher alcohols for the production of mixed esters of chloromaleic acid maybe mentioned methanol, ethanol, tertbutyl alcohol, hexanol, benzyl alcohol, beta-phenylethyl alcohol, ethylene chlorohydrin, propylene chlorohydrin, ethylene glycol monomethyl ether, etc.

The present esters of chloromaleic acid range from clear, limpid liquids to waxy or even crystalline solids, depending upon the nature of the alcoholic portion of the molecule. They are particularly useful in the preparation of new, highly heat-resistant resinous or rubbery copolymers as disclosed in my copending applications, Serial the i to non H. .cooa n. .0

wherein R is an alkyl group of at least 8 carbon atoms. The above reaction takes place even atordinary room temperature, and inthe absence of either a catalyst or a dehydrating agent. If an excess of the alcoholic component be employed,

the reaction product is usually a solution of the mono-ester in the unreacted alcohol. This shows that the reaction is unimolecular and that under the'mild conditions employed. no diesteriflcation occurs. The mono-ester, if solid at room temperatures, is thus readily obtained by crystallization.

If it is a liquid, it may be separated from thecrude reaction product either by vacuum distillation, solvent extraction, etc. For many purposes,

especially for the preparation of'resinous or rubbery materials, isolation'of the mono-ester from the reaction product is not necessary. The reaction product, containing either the substantially pure mono-ester or a mixture of the ester with the excess of alcohol or anhydride, depending upon the reactant quantities employed, may

be used as such for copoiymerizing reactions with a vinyl compound or a dioleflnic compound or a mixture of the same.

If it is desired to prepare a di-ester from chloro-i maleic anhydride, subsequent esteriflcation of the initially formed mono-ester takes place upon heating the mono-ester, preferably at refluxing temperatures, in the presence of at least enough of the alcoholic component to allow 'di-esteriflcation. Since reaction of the mono-ester with an alcohol takes place with formation of water a dehydrating catalyst may be advantageously employed in this step, or provision may be made for removing reaction water, for example, by use of a water-trap. However, esterification of the mono-ester usually takes place so readily that only the application of heat is ordinarily required. The diesters may likewise be prepared by esteriflcation of the free acid, by ester interchange, or by dehydrohalogenation of the corresponding 1,2- dichiorosuccinates.

' The invention is further illustrated, but not limited, by the following example:

Example A mixture consisting of one mol of chloromaleic anhydride and 286 grams (2.1 mols) of 2-ethylhexanol was heated on a steam bath for one hour. At the end of this time formation of the mono-2-ethylhexyl ester of chloromaleic acid was substantially completed. In order to prepare the di-ester, 2 cc. of concentrated sulfuric acid and 50 cc. of benzene were added to the reaction mixture and the whole was refluxed for a period of approximately hours in a reaction vessel equipped with a water-trap. During this time.

i 4 showed substantial completion of the esteriflcation. The excess alcohol was then distilled oil from the product under reduced pressure, and

the residue was washed with water, sodium carbonate, hydrochloric acid and then again with water. Water was removed from the product by distillation with benzene, and after removal of the benzene the product was recovered by distillation. There was thus obtained as a colorless go liquid the substantially pure bis(2-ethylhexyl) izhioromaleate, B. P, 204-206 C./6 mm., n

The bis(2-ethylhexyl) chloromaleate may be advantageously employed inthe preparation of resinou materials, for example, by copolymerization with styrene or other oleflnic compounds as disclosed in my copending application, Serial No. 509,785, flied November 10, 1943.

Instead of 2-ethylhexanol I may employ other alcohols of at least 8 .carbon atoms for the production of either the corresponding mono-esters or the corresponding di-esters of chloromaleic acid by the procedure described above for the preparation of 2-ethylhexy1 hydrogen chlorogg maleate or the subsequent esteriflcation product,

bis( 2-ethylhexyl) chloromaleate. When preparing the higher esters, wherein either the alcohol or the product may be a solid, it is advantageous to employ a diluent at the beginning of the .9 reaction in order to bring about a smooth reaction.

In the preparation of such higher esters it is also preferable to operate under pressure, for example, in a rotating autoclave.

As may be apparent to those skilled in the art,

88 the use of 2 mols of the alcohol per moi of the anhydrlde is not necessary when the mono-ester isthe final product desired. Since the excess of the alcohol acts as a diluent in the preparation of the mono-ester, it is advantageously employed 0 even for the production of the mono-ester, and

in absence of such an excess of the alcohol it is desirable to employ an extraneous solvent or diluent. As solvents or diluents there may be employed any liquid material which is inert under reaction conditions, for example, benzene, xylene,

petroleum ether, nitrobenzene, etc. The solvent or diluent should have a boiling point which is lower than that of the reaction constituents in order to permit refluxing of the same.

As esterifying catalyst in the preparation of the diesters any acidic material which is known to catalyze dehydrating reactions may be employed. Instead of sulfuric acid I may use other mineral acids, for example, phosphoric acid, or

55 such organic acids as the lower aliphatic carboxyiic acids or the aromatic sulfonic acids, for example, para-toluenesulfonic acid, benzylsulfonic acid, etc. Preferably, no catalyst isemployed in the preparation of the mono-esters.

6 Esterifying catalysts and extraneous diluents or solvents are also advantageously employed in the preparation of the diesters by reaction of chloromaleic acid with an alcohol of at least 8 carbon atoms. When effecting the preparation of the as present esters by ester-interchange, for example,

additional diluent, depending upon the nature of the higher alcohol employed.

The present higher esters of chloromaleic acid are particularly suited for the production of resinous copolymers with vinyl compounds because 18 ml, of reaction water separated oil, which 15 they confer not only a heat-resisting property to '5 the final product but they also impart plasticity and consequent increase in toughness to the resinous products. Since the presence of the chlorine atom on the ethylene carbon appears to accelerate copolymerization, the present invention thus provides for the synthetic resin industry materials which impart plasticity to a resin by ready incorporation of the same into the framework of the resin molecule.

While the present chloromaleates are particularly valuable for the production of synthetic resinous and rubbery materials, they are also valuable as intermediates in the production of a large variety of other industrially useful materials.

The chlorine atom and the oleflnic double bond of the chloromaleates facilitates the use of these esters for the preparation of surface active agents, for example, by substitution of the chlorine atom by a long-chain radical and subsequent sulfonation of the product at the double bond of the molecule. The higher chloromaleate esters may likewise be advantageously employed for the preparation of water-repelling agents, for example, by reaction with alkyl amines, alkylol amines, ethylene I glycol, pyridine and formaldehyde, etc.

RAYMOND 1 3. ,SE'YMOtlR.

REFERENCES CITED The following references are'oi record the file of this patent:

Walden, 'Zeitschrift fiir Physikalische Chemie, vol. 20 (1896) p. 380.

Havinga et al., Chemisch Weekblad," vol. 34

(1937), pp. 694-701. (Available inScientiflc Library.)

Tomas-Mamert,v BulL de la Soc, Chim. de France," Series 3, vol. 13 (1895), p. 848.