Water Number of Nonionic Surfactants, III.

Polyoxy Alkylene Derivatives of Fatty Alcohols

Abstract

The water number (W. N.) of polyoxyethylene derivatives of fatty alcohols and of polyoxypropylene cetyl ethers (general formula CP_aE_b:where C is cetyl alcohol, P propylene oxide, E ethylene oxide, and a and b are numbers of moles added, respectively) was measured and studied with relation to the properties of these derivatives.
(1) Polyoxyethylene derivative of fatty alcohols : A tendency that the W.N. increases linearly with increase of the mole number of E was observed, but it gradually began to deviate from the linearity and became smaller through the maximum. When the mole number of E is above 100, it was observed a tendency that the W.N. converges to a range from 11 to 12.
(2) CP_aE_b : (a) If CP_a, polyoxypropylene cetyl ether, is assumed as an oleophilic group, the feature of increse in W.N. with increase in mole number of E was almost the same as in the case of usual nonionic surfactants. (b) Solubility of these derivatives against water could be clearly classified by the magnitude of W.N.
(3) For the raw material to which the ethylene oxide was reacted, it was confirmed that the difference in W.N. corresponding to the increase in the carbon number by 24, from CP₀ to CP₈, are approximately equivalent to the difference in W.N. corresponding to the increase in carbon number of saturated fatty alcohols by 2 from C₁₆ to C₁₈.