United States Patent (19) 11 4,376,789 Lowicki et al. (45) Mar. 15, 1983 (54) SURFACTANTS WHICH ARE POLYHYDRIC 4,150,041 4/1979 Suzuki et al. .................... 260/346.6 ALCOHOL PARTIAL ESTERS OF ADDUCTS OTHER PUBLICATIONS OF MALE CANHYDRDE WITH AN UNSATURATED CARBOXYLECACID Sastry et al.-J. Amer. Oil Chem. Soc., vol. 48 (1971), pp. 686-688. 75) Inventors: Norbert Lowicki, Duisburg; Rheineck et al.-Fette-Seifen-Anstrichmit, vol. 71 Natvarlal B. Desai, Dinslaken, both (1969), pp. 644-652. of Fed. Rep. of Germany Nagakura-Chem. Abst., vol. 91 (1979), p. 22764h. 73) Assignee: Grillo-Werke AG, Vainer et al.-Chem. Abst., vol. 76 (1972), p. 29524d. Duisburg-Hamborn, Fed. Rep. of Nagakura et al.-Chem. Abst, vol. 83 (1975), p. 27496s. Germany Dow-Chem. Abst., vol. 83 (1975), p. 178328q. Bibby-Chem. Abst., vol. 88 (1978), p. 22149Z. 21 Appl. No.: 240,606 Suzuki-Chem. Abst., vol. 89 (1978), p. 76632r. (22 Filed: Mar. 4, 1981 Asao et al.-Chem. Abst, vol. 84 (1976), p. 91,967u. (30) Foreign Application Priority Data Broniarz et al.-Chem. Abst, vol. 79 (1973), p. 7158x. Primary Examiner-Sam Rosen Aug. 29, 1980 IDE Fed. Rep. of Germany ....... 3032612 Attorney, Agent, or Firm-Merriam, Marshall & Bicknell 51 Int. C. ..................... A61K 47/00; A61K 31/70; CO7H 13/06; C07C 69/74 57 ABSTRACT 52 U.S. C. .................................... 424/361; 424/180; Disclosed are novel polyhydric alcohol partial esters of 424/314; 424/365; 536/119; 560/123; 562/505; polycarboxylic acids from Diels-Alder adducts of ma 252/174.18; 549/245 leic anhydride and a straight chain unsaturated carbox 58) Field of Search ..................... 260/346.6; 536/119; ylic acid having ten to twenty-five carbon atoms. The 424/180, 314, 361; 562/505; 560/123; 252/108, partial esters can be subsequently sulfated. 121, 142, 174.18 The polyhydric alcohol can be a mono- or disaccharide 56) References Cited such as sucrose or mannose. U.S. PATENT DOCUMENTS The partial esters are surfactants which are der matologially acceptable and useful in personal products 2,137,616 11/1938 Hunn ................................ 260/346.6 2,839,550 6/1958 Wiggerink et al. ... 260/346.6 and skin-care products. 3,053,830 9/1962 Gaertner ............................. 536/119 3,219,657 11/1965 Gaertner ............................. 536/119 12 Claims, No Drawings 4,376,789 1. 2 A specially advantageous property of the partial es SURFACTANTS WHICH ARE POLYHYDRC ters of the invention is their compatibility with hard ALCOHOL PARTAL ESTERS OF ADDUCTS OF water, with which they generate no precipitates. MALE CANHYDRDE WITH AN UNSATURATED Another surprising advantage is that the sugar esters CARBOXYLIC ACD 5 of the invention are readily and easily produced on a large scale. According to Industrial Engineering Chem This invention is concerned with partial esters of istry, 48 (1956), pages 1459 to 1464, sugar esters are polyhydric alcohols, especially of mono- and disaccha produced, for example, by ester interchange of fatty rides, with the polycarboxylic acids which result from acid alkyl esters with sugar in dimethyl formamide in the Diels-Alder adducts of maleic anhydride with sim 10 the presence of an alkaline catalyst at about 90° C. The ple unsaturated carboxylic acids having a chain length reaction time amounts to about 12 hours and purifica of C10 to C25 and which, if desired, can be sulfated. tion of the reaction product is difficult, especially as to Further, the invention is concerned with processes of complete removal of the dimethyl formamide. A nearly producing these products, as well as with their use as quantitative recovery of this solvent is important for dermatologically acceptable nonionic and/or anionic 15 economic reasons. On the other hand, dimethyl form surfactants in cosmetic preparations. amide is not physiologically acceptable. Despite careful The Diels-Alder adducts of maleic anhydride with purification of the sugar ester obtained in this manner, simple unsaturated carboxylic acids are known. They for example a sucrose ester, small amounts of the physi can be saponified with alkali, and their esters and am ologically objectionable dimethyl formamide remain in ides, especially their reaction products with triethanol 20 the end product and which, furthermore, cause a dis amine, are useful as anticorrosives; cf. U.S. Pat. No. agreeable odor. 3,985,504. The alkali salts have already been used to According to German published patent application prevent formation of deposits from hot seawater; cf. No. AS 2022 880 the ester interchange of fatty acid Great Britain Pat. No. 1,551,894. esters with sucrose can occur through addition of 1 to The chemical structure of the adducts is not fully 25 40% by weight of an alkali-free alkali salt or soap of explained, since statements in the two above-mentioned saturated and unsaturated fatty acids, as a catalyst. The patents are contradictory. According to U.S. Pat. No. ester interchange is carried out at 160 to 190 C, within 3,985,504 an addition of carbon atoms takes place next 20 minutes. After termination of the reaction, the re to the double bond, with the double bond remaining maining mixture is rapidly cooled and the unreacted preserved. According to Great Britain Pat. No. 30 sucrose, as well as the soap used as a catalyst, are re 1,551,894 cyclobutanedicarboxylic acids are obtained. moved. Although the process operates without sol In any case, through hydrolysis of the adducts, tri- and vents, the cost of preparing the alkali soap is very high. poly-carboxylic acids are obtained. To prepare alkali-free soap, the alkali metal hydroxides It has now been found that polyhydric alcohol partial are first dissolved in aqueous methanol under nitrogen esters, especially of mono- and disaccharides, with poly 35 by heating at a reflux temperature. Afterwards, the carboxylic acids which result from a Diels-Alder ad methyl ester of the selected long-chain fatty acid is duct of maleic anhydride with at least one unsaturated added and the mixture is heated for 40 to 60 minutes carboxylic acid having a chain length of C10 to C25, under reflux. The methanol is then vacuum distilled possess unusual and extremely valuable properties. The from the soap formed in the process. unsaturated carboxylic acid desirably has a straight 40 A further disadvantage of the described process is carbon chain. It has been found that these partial esters that yields of the sucrose ester amount to only about 43 are excellent dermatologically acceptable nonionic sur to 48%. This is because it is difficult to control the high factants especially suitable for use in cosmetic prepara reaction temperatures so as to prevent disintegration of tions. Surprisingly, these partial esters can be sulfated reactants, and the product, from occurring. under gentle conditions, with the double bond of the 45 According to German published patent application unsaturated carboxylic acids remaining unaltered as No. AS 24 12 374, sucrose can be ester-interchanged shown, for example, by the iodine number of the prod with a triglyceride at 100 to 170° C. with use of alkaline ucts. The sulfated partial esters likewise form extremely catalysts. The yield of sucrose esters after 10 to 22 hours useful dermatologically acceptable anionic surfactants of reaction time is between 11 and 40%. Solid products which are likewise especially suitable in cosmetic prep 50 are produced which are insoluble in water, or which are arations. soluble only with great difficulty in water, and which The sulfated partial esters of mono- and disaccharides react with the mineral content of the water. are the first sulfated sugar esters and they are especially The process according to German published patent useful in producing mild cleansers and dermatologically application No. AS 24 12374 cannot be applied to the acceptable detergents. 55 production of unsaturated fatty acids since the long The sulfation can be carried out in such mild condi reaction times lead to formation of resinous products tions, namely at temperatures below 100 C., with so with insufficient dispersibility in oil. Finally, working dium sulfite, that the process is not by any means com up of the sucrose esters produced in low yield is very parable to the usual sulfation of olefins. It is believed, expensive. therefore, that in the sulfation of the products of the 60 According to the invention, partial esters of polyhyd invention, a substitution takes place on an activated ric alcohols, particularly mono- and disaccharides, in carbon atom of the maleic acid molecule. The partial cluding partial esters of mannose, glucose and the very esters of mono- and disaccharides, according to the sensitive sucrose, can be produced at 85 to 90 C. invention, provide a completely new type of sugar ester within a reaction time of 1 to 5 hours by reaction with and sugar-based surfactant, which by reason of their 65 the adduct or a polycarboxylic acid formed by hydroly favorable toxicological and dermatological properties, sis of the adduct. The partial ester products thus ob are clearly superior to most, if not all, products hitherto tained are completely water soluble and provide, from known. the outset, excellent compatibility with the skin and 4,376,789 3 4. mucous membranes. In the process of the invention, the ylic acid which then desirably is esterified with ethylene reaction is carried out without solvents. In addition, glycol. Thereafter, these partial esters can be subjected about 5 to 10% by weight of an alkaline material, for to ester interchange with the polyhydric alcohol. In this example sodium hydroxide, potassium carbonate or manner, especially pure and very compatible partial trisodium phosphate, can be used as the catalyst. Surpis ester products are obtained which are produced under ingly, as the reaction progresses, the viscosity of the the most gentle conditions.