SYNTHESIS OF PYRIDINE-MOIETIES-CONTAINING POLY(ACYLHYDRAZONE)S AND SOLUTE SEPARATION THROUGH THEIR MEMBRANES

Poly(acylhydrazone)s containing pyridine moieties were synthesized from 2,6-pyridinedicaboxaldehyde and each of five dihydrazides. Although most of the polycondensates were insoluble or sparingly soluble and of low molecular weight, the polymers from malonyldihydrazide were highly soluble and readily gave tough films. Their performances as separation membranes were examined in reverse osmosis, gas separation, and pervaporation (PV). The membranes showed a good performance in PV and were water permselective for aqueous alcohols and aprotic solutes, showing to be very effective to break azeotropes with high separation factors and to preferentially separate water from high concentration feeds, particularly in butanols and THF. Deviation from ideal flux, swelling degree, and some physicochemical parameters such as solubility parameter, molar volume, and vapor pressure were correlated to the membrane performances in a wide range of feed concentrations of the above two solute groups. (C) 1995 John Wiley & Sons, Inc.