FATTY ACID ALKYLOLAMIDES (ii) commercial second- ary alkyl sulphate FC FC FC FC FC FO FO FO 0 O W (iii) commercial dodecyl benzene sulphonate FC FC FC FC FC FO FO FO FO O W In detail, the test consisted of making a 10 per cent solution of the mixture of soap and detergent in distilled water. 5 c.c. of this solution were then mixed with 45 c.c. of hard water (200 parts p.p.m. of CaO), and 5 c.c. of this dilution were further diluted with 45 c.c. of the same hard water. These last dilutions were examined next day for the condition of the lime soaps. It might at first be thought that, ideally, soap-detergent mixtures for shampoos should consist predominantly of soap, and only contain a suffici- ency of detergent to keep in suspension lime soaps produced during the washing operation. In practice, however, it is found that soap has a specific effect to reduce the degreasing power of sulphated acyl-alkylolamide deter- gent preparations, and, in consequence, mixtures containing quite high proportions of the latter are reasonably mild from a degreasing standpoint. Normally, the high lathering alkylolamides based on the C•/C•4 type fatty acids (for which the figures above are quoted) are preferred for shampoo preparations. Products based on unsaturated fatty acids of the type have, however, an even higher lime soap dispersive power, and practical tests using these in conjunction with soap have yielded excellent results for hair washing under test conditions. Particularly interesting is the success obtained with these preparations on hair which had been submitted to repeated bleaching operations over a period, or to several permanent waving treatments. The results in these cases were considerably more successful than those obtained using shampoo preparations of the more conventional types. The best-known of the second group of water-soluble fatty acid alky- lolamides falling within our classification (a) are the derivatives of fatty acids with diethanolamine. These and related compounds were the subject of the early basic patents on fatty acid alkylolamides in the U.S. To-day such are offered by a number of different firms in the U.S. under various names such as •-100, DIANOL G, ALROLSOL, etc., but they are most associated with the name NINOL*. In addition to diethanolamine, a wide range of alkylolamines, containing two or more primary alcoholic groups, may be employed and likewise a less wide, but none the less extensive, range of fatty acids may be employed. Obviously, therefore, the number of different possible combinations and in consequence the number of potential compounds is big. Many of these have achieved commercial importance for special purposes and the American range of products is to-day extensive. A range of similar products is offered over here under the name LOaA•INE. The products derived from diethanolamine and C • •/C •4 type fatty acids have * Ninol Laboratories, Chicago, U.S.A. 173

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS in recent times become particularly important, not only as detergents in their own right, but on account of their ability to enhance the foaming characteristics of sulphated detergents in the presence of oily soiling matter. This is the subject of U.S. patent No. 2,607,740. At first, products based on the mixed fatty acids of coconut oil were considered satisfactory, but with the commercial availability of pure fractionated lauric acid it has been found that, despite the greater price of this material, it is a preferable starting point, as the effectiveness of the finished product is more than proportionately higher in relation to its higher cost. Like the sulphated fatty acid alkylolamides, such compounds as lauric diethanolamide can be used in conjunction with soap to produce effective shampoos. They show certain advantages and certain disadvantages in comparison with the sulphated products. On the credit side, they are less substantive to the hair, but on the debit side they are less effective as lime- soap dispersing agents. Nevertheless, highly satisfactory combined prepara- tions can be made, and, using soaps derived from alkylolamines, such as monoethanolamine or triethanolamine, rather than from soda or potash, clear liquid or translucent gel preparations can be formulated having great consumer appeal. Gel preparations having the consistency of soft petroleum jelly have in many ways the ideal consistency and appearance for a shampoo. Application is easy and the products are comparable in this respect with a good cream shampoo, but the transparency or translucency adds that same sales appeal that has kept transparent soap popular for so long. Gels based on soap alone were far too slowly soluble to be successful, but combinations of fatty acid alkylolamide and soap can be devised having a sufficiently rigid gel consistency, yet dissolving rapidly in warm water. Patent specifica- tions have been applied for in this connection. The products based upon C•2/C•4 fatty acids and diethanolamine find some application as emulsifying agents and are particularly effective when used in conjunction with non-ionic detergents of the type obtained by condensing ethylene oxide with alkyl phenols. Products of this kind are used in bulk for the production of all-purpose detergent liquids, horticultural sprays, etc., but they are also of interest to the cosmetics chemist as emulsifying agents. Condensates based upon diethanolamine with C•2/C•8 unsaturated fatty acids are good oil-in-water emulsifiers for mineral oil. The third group of water-soluble derivatives falling within our classifica- cation (a) are those where a simple fatty acid alkylolamide has been con- densed with ethylene oxide to give compounds corresponding to the formulas below: (2) /(CH,.CH•.O)•H R.CO.NH. (CH•.CH•.O),•H R.CO.N •(CH•.CHa. O)•H 174