THE ACTIVITIES OF SOME WATER-IN-OIL EMULSIFYING AGENTS 179 alcohols) can be shown to contain at least 18 groups of compounds (Fig. 4). Most of the unidentified compounds are steroids. The known composition of Hartolan has been effectively summarised in Table 1, but in addition to the alcoholic compounds listed, there is also a small amount of unsaponified ester. o 2. 00 o o Figure 4. Two-dimensional thin film chromatographic pattern of Hartolan (kindly provided by B. Bush, Esq.). Developing solvents :-- 1. cyclohexane/benzene/acetone: 3/1 [1 Key 1. esters and hydrocarbons 2. cholesta-3,5-dien-7-one 3. isocholesterol 4. aliphatic monols 5. cholesterol 2. benzene containing 12% ethanol 6. 7-oxolanostenol 7. 7,11-dioxolanostenol 8. 7-oxocholesterol 9. aliphatic diols 10. cholestane triol Hartolan is not easily resolved into its individual components so that ideas about its emulsifying power are based on the behaviour of representative pure compounds. Three main groups of compounds can be distinguished: aliphatic alcohols, steroids containing 27 carbon atoms per molecule and steroids (sometimes referred to as triterpenes) containing 30 carbon atoms per

180 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS molecule. The emulsifying powers of representatives of each group are shown in Figure 5. Comparison of the emulsifying powers of the crude fractions obtained from Hartolan with those of the representative compounds shows that the 500 ! " • c• 400 2oo I I I I (a (c) o 2 • 6 8 IO Concer•Pr'ctt'/Dn (• ) Figure ,5. Water numbers of alcohols as a function of their concentrations in liquid paraffin (a) cholesterol' (b) isocholesterol (c) neicosanol impure materials usually have the greater water numbers. Although it is well known that a mixture of related surface-active agents is usually more effective than a single compound, Table 3 also reveals that it is possible to obtain an enhancement of the emulsifying power by mixing an emulsifying agent with a non-surface-active compound of the right type. It may be seen that for 2.5ø,/0 lanolin alcohols in liquid paraffin, the water number is 255 while that of the lanolin esters is negligible. If, however, the two materials