262 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS W.N.'s of the new surfactants, which range approximately from 20 to 30, evidently surpass that of SSO (ca. 14) or POE-OLE (ca. 15) and manifest one of their distinctive features. This prominent water-retention capacity implies superiority in emulsifying power and may facilitate the formulation of w/o emulsions with a large water content which would be far preferred by most consumers. Another investigation was undertaken on their dispersive ability in liquid paraffin, using titanium dioxide as a dispersoid. The new surfactants displayed excellent dispersive power (Table V). Interaction of metal with a lone pair of a nitrogen atom (a Table V Dispersion of TiO2 in Liquid Paraffin in the Presence of W/O Emulsifiers Absorbance Compound (at 300 nm) OL--DEA 1.41 OL--AMPD 1.59 OL--AEPD 1.51 OL--TMAM 1.50 POE--OLE 0.01 Absorbance Compound (at 300 nm) OLA--DEA 1.32 OLA--AEPD 1.05 OLA--TMAM 1.01 SBA--DEA 1.10 SBA--AMPD 1.64 SBA--TMAM 1.21 SSO 0.10 stronger electron-donor than an oxygen atom) present in the hydrophilic group, seems to account for such property. Participation of a nitrogen atom may also be one of factors responsible for their large water number. These results suggest some measure of success in formulating w/o cosmetics containing pigments and large amounts of water. The stability of a w/o emulsion composed of surfactant (5%), liquid paraffin (28%) and water (67%) was also evaluated in terms of the degree of oil-phase separation with the lapse of time after preparation, along with the change of the particle size of water droplets. W/O emulsions obtained with the new emulsifying agents exhibited better storage stability, as shown in Table VI and Figure 1, which, taken in conjunction with Table VI Stability Evaluation of W/O Emulsions (at R.T.) Volume (%)a Compound 48H b 10D c 1Y • Volume (%) OL--DEA 94.4 91.2 80.8 OL--AMPD 100 97.0 93.9' OL--AEPD 96.6 91.1 86.4' OL--TMAM 100 95.0 73.3 POE--OLE 93.9 90.9 63.6 Compound 48H 10D 1Y OLA--DEA 100 95.0 83.9 OLA--AMPD 100 99.5 75.0 OLA--AEPD 99.5 92.9 OLA--TMAM 100 97.1 74.2 SBA--DEA 97.5 93.5 76.7 SBA--AMPD 100 94.1 74.4 SBA--TMAM 100 100 78.9 SSO 99.0 90.6 73.7 aRepresents the proportion of emulsified layer. bHour. CDay. •Year. 'Two months later.

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