SYNTHETIC salts we have what was probably one of the first commercially avail- ' able type cationic agents, the Sapamines, made by the acyla- tion of an unsymmetrical dialkyl : ethylene diamine with a fatty acid chloride. R.CO.C1 q- H•N.C•H•.N(C•.H•)• "' ---•R.CO.NH.C:H4.NiC•Hs) • oleyl chloride being used in the Sapamines. The fatty esters of primary, secon- dary and tertiary hydroxy amines are used in the textile industry. The product Emulphor F.M. or Empilan F.M. is the mono oleate of triethanolamine, and the softening agent Soromin S.G. is prepared by reacting triethanolamine with stearic acid then treating the ester with an aqueous solution of formic acid to .give the ester salt. The F.M. type of product is an excellent water-in- oil emulsifying agent for mineral oils and has uses as a stabiliser for oil-in-water emulsions. Among the quaternary and amine salts of interest to the cosmetic chemist we have cetyl trimethyl ammonium bromide (Cetavlon) and the Velan PF series based on Steara- mide methyl pyridinium chloride. made by heating stearamide with formaldehyde and pyridine hydro- chloride. Lissolamine A or Cetavlon is cetyl trimethyl ammonium bromide. Triton X400 is lauryl dimethyl benzyl ammonium chloride. (This was introduced originally as "Zephirol," made by methylating DETERGENTS a primary amine and quaternising with benzyl chloride.) NONIONIC TYPES The main advantages of nonionic products are: (1) their relative stability to high concentration of electrolytes, (2) the degree of solubilisation conferred by polar groups is more easily controlled than is the case with ionising surface- active agents. It has been reported that one sulphate group is approximately equal in solubilising effect to 4 ethylene oxide (OCH •_CH2) groups. The main divisions of the nonionic products are the ethylene glycol polyethers and the poly-glycerol derivatives. The general formula of the ethyl- eneglycol polyethers is: R([CH •CH •O] raH)n and they are made by the condensa- tion of an insoluble compound con- taining reactive hydrogen atoms, e.g., a carboxylic acid, amine, amide or Mercaptan with the alkylene oxide according to the following reaction CH• -- CH• R.OH q- n •k// ---- 0 R--O--C2H•(OC•I•4)•OH Representative of this type of pro- duct are the Emulphor 0 types, certain Igepals and Leonils and Lissapol NX and N. Emulphor O = Sperm oil and 20 tools. Et20. Emulphor ELN = Dodecyl phenol q- 20 tools. ErgO. 209

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Emulphor EL = Castor oil d- 40 mols. Et•O. Dismulgan III = Dodecyl phenol + 30 mols. Et •0. Triton NE = Alkyl phenol Et•O. Igepal B Conc. = Iso-octylphenol 3 tools. Et•.O. Leonil LS = Hexyl/heptyl/ betanaphthol 4 Et•O sulphate. Empilan AQ = Laufic acid polyglycol. Polyglycerol ethers may be exem- plified by the following formula R(OC2HsOH)nOH Other nonionic surface-active agents include the very important glycol and glycerol fatty acid esters, e.g., glycerol mono stearate, glycol mono stearate and the like. These have very considerable importance in the foodstuffs industry. A further important type of deter- gent which is used in cosmetics and in industry is made by the condensa- tion of 2 molecules of diethanolamine with 1 molecule of a fatty acid, at 150-170 ø C. This type of product is sold under various trade names, chiefly in the United States, such Alrosol, Dianol, Ninol, etc. The main reaction is R.COOH d- HN(C•H•OH)• fC•H,OH R.CON X d- H•O C•H,OH The oil-soluble surface-active (emulsifying) agents comprise cer- tain Spans, pentaerythritol and gly- cerol esters, etc. This type of pro- duct is manufactured by heating together the alcohols, for instance, glycerol, mannitol, etc., with the desired fatty acid, for instance, stearic, lauric, etc., in the presence of a catalyst yielding a very valuable range of cosmetic emulsifying agents. SEQUESTERING AGENTS Of considerable importance tech- nically are the water softening agents exemplified by the Trilon B. type of product. This is the sodium salt of ethylene diamine tetra acetic acid and is capable of sequestering cal- cium, barium, magnesium, iron ions from aqueous solutions. The seques- tering action is thought to be due to the formation of stable complexes, where the metal ion is held by co- ordinate bonds to the nitrogen atom as well as by salt linkages to the carboxylic groups. HOOC.CH•. CH•.COOH 'x / NCH•.CH•N HOOC.CH• CH•.COOH ANALYSIS AND EVALUATION Turning now to the analysis and evaluation of synthetic detergents used in cosmetic practice, it is usual to make the following analytical determinations both on raw materiMs and on finished shampoos: 1. Active Matter Content by Cat- ionic Titration. As is well known, anionic detergents are incompatible with cationic detergents, a complex compound is precipitated when solu- tions of the two types are mixed together, and this fact is made use of in a method of estimation of the active matter content of detergent-- 210