Optimization of the transport of aminic substrates

A series of aminic substrates were transported and separated by means of a chloroformic liquid membrane. Several system parameters (source phase pH, r eceiving phase pH, carrier concentration, substrate concentration, stirring rate, transport duration) were investigated in order to determine the best experimental conditions that allow a proper separation of aliphatic and ar omatic amines from aqueous mixtures. As the substrate started to be transfe rred against its concentration gradient, the part played by the carrier bec ame more important. The results were analyzed assuming that the global tran sport experiment consisted of a series of extraction equilibria taking plac e simultaneously at the two water-membrane interfaces, and considering that the rate determining process was the diffusion of the neutral substrate, a nd its association with the carrier through the organic membrane. Aniline c ould be successfully separated from dimethylaniline, and di-n-butylamine, a nd cyclohexylamine from morpholine, fact that encouraged the working out of the environmental aspects of our project. (C) 2001 Elsevier Science B.V. A ll rights reserved.