CHEMICALS FROM FATS AND OILS 91 simplest and most direct approach to derivative formation. The alkali metal soaps are basically cleaners and detergents, but function, in cos- metic preparations, as auxiliary emulsifiers and foamers also. Zinc and magnesium stearates have found use in face powders for improving skin adhesion and for supplying smoothness to the touch aluminum stearate has functioned as an oil thickener and gel former. The amine salts or soaps, e.g., the ethanolamine or morpholine derivatives, are known useful emulsifying and permanent waving agents. Esterification, with mono- or polyfunctional alcohols or with amino alcohols, gives the simple or polyfunctional esters. All of these function primarily, in the cosmetic industry at least, as emulsifiers for wax or oil and water emulsions, and have found application in cold creams, vanish- ing creams, and permanent waving creams. The esters, however, are also useful per se as intermediates in fur- ther chemical synthesis. They can be reduced by catalytic hydrogenation or by sodium emulsion to the corresponding alcohols. These, in turn, have found some use as flotation frothers, lubricants, and solvents, and in the cosmetic industry are very familiar auxiliary emulsifiers and skin sof- teners and aid in the emollient action of cold creams. The alcohols func- tion in o/w or w/o emulsions and are excellent for the preparation of lano- lin or petrolatum emulsions. Condensation products of the alcohols with certain cellulose products have been useful for suspending insoluble powders in cosmetic preparations, and oleyl alcohol has been used as a superfarting agent and a dispersing agent for dyes in indelible lipsticks. Sulfation of the alcohols, using sulfuric acid or SOa, gives the corre- sponding long-chain alkyl sulfates which, as the sodium, ammonium, or organic amine salts, are superior detergents, emulsifiers, and foaming agents. They are used as such in the cosmetic industry. The hydroxyl grouping in the alcohols offers another fruitful approach for synthetic purposes, namely the interchange with halogen to give the corresponding long-chain halides. These, in turn, may be used as al- kylating agents, as quaternizing agents, or as chemical intermediates. They will, for example, react with sodium sulfide to give the alkyl mer- captan, which is one means of introducing a sulfur atom into the molecule, This opens up an approach to use in the rubber industry, as a vulcanizer, for example. Another common reaction of the fatty acids is their conversion to the acid chlorides, by way of phosphorous trichloride or thionyl chloride. These are obtained in good yield and are extremely reactive intermediates. They will undergo amide or ester formation, with amines or alcohols with which the free acids often will not react. They will, for example, react with sodium methyl tauride to give the so-called Igepons, synthetic deter- gent additives, and emulsifiers. This is a generalized type of reaction and

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS can be carried out with many such compounds. And finally, under the proper conditions, they will condense with aromatic hydrocarbons to give the alkyl aryl ketones. The fatty acids can also be successfully condensed, catalytically, to the dialkyl ketones, with the combination of two mols of acid and the loss of one mole of water and one of carbon dioxide. These may be mixed ketones, for example, the methyl-stearyl ketone or symmetrical ketones, the di- stearyl ketone, or stearone as it is sometimes called. These have found some use as antiblocking agents, flatting agents, and as wax additives, They have had some preliminary screening in the cosmetic field too. Stearone has been tried in hand creams as a wax substitute and skin conditioner, and as a gelation agent in waterless hand cleaners it helps to keep the prod- uct from liquefying over 100øF. Oleone has been used as a substitute for cetyl alcohol for supplying oiliness in lipsticks. Attack on the hydrocarbon end of the fatty acid molecule is somewhat more limited than is the case with the carboxyl group, although several interesting reactions are possible. One can, for example, oxidize the double bond in the unsaturated acids. Specifically, oxidation of oleic acid with nitric or chromic acid, or by ozoni- zation gives the dibasic azelaic and the monobasic pelargonic acids. These are finding use as plasticizers, low-temperature lubricants, and in the syn- thetic fiber industry. The more highly unsaturated acids, like linoleic, can undergo dimerization, a joining of two molecules through the double bonded system. This gives a viscous product useful as a high-temperature lubricant. The use of per acids, such as peracetic or performic, in fatty acid synthetic work is increasing at the present time too. It represents a useful procedure for the preparation of dihydroxy stearic acid from oleic acid, for example, and for hydroxylation and epoxidation of the glycerides themselves. These, or their esters, are useful as plasticizers in the prepara- tion of synthetics. Halogenation is another reaction that occurs readily with the fatty acids, with preferential addition to the c•-carbon atom, but with chain polyhalogenation possible if the reaction is pushed. And recently, too, the use of liquid SOa in the preparation of the c•-sulfonic carboxylic acids has aroused renewed interest in these compounds as po- tential emulsifiers or as detergents or detergent additives. Let us turn our attention, now, to nitrogen chemistry, to the nitrogen- containing fatty acid derivatives. My company, one of the leaders in the commercial production of these compounds has, I believe, contributed as much or more than any other company to the fundamental chemistry involved and to the determination of the physical and chemical properties of these derivatives. Many of the compounds mentioned in the following discussion, therefore, are of necessity products of its laboratories'and bear its trade-mark.