Figure 5From: Basic surface-active properties in the homologous series of β-alkyl (C12H25/C18H37) polyethyleneoxy (n = 0-20) propionamidesBlock diagram of operations of the process of purification by liquid-liquid extraction (petroleum ether, b.p. = 30-60°C/ethyl alcohol 96%) of “heterogeneous” polyethoxylated (n = 3-20) higher alcohols R(EO) n H, of free higher alcohols (ROH) (adapted from Schick, M., 1987) [[8]].Back to article page