Dehydration of benzene through fluorine containing aromatic polyamide membrane by pervaporation

摘要

A series of soluble polyamides were synthesized by direct polycondensation of the 5-tert-butyl isophthalic acid with different diamines. Solution (20%) of the polymers ill suitable solvents was used to cast the membranes. The membranes showed selectivity toward the benzene (Bz) in A mixture of Bz/water (H2O). Water affinity of the membrane Was found to be lower than that of Bz. The polyamide incorporating hexafluoro isopropylidene moiety was promising for the dehydaration of Bz and breaking of Bz/H2O azeotrope. The polymers exhibited inherent viscosities, ranging from 0.40 to 0.92 dL/g and 10% weight loss in synthetic air Lip to 474 degrees C Glass transition temperature measured by DSC and DMA reached up to 258 degrees C. The membranes were pale yellow in appearance having tensile strength up to 85 MPa, modulus of elasticity up to 2.6 GPa, and elongation at break up to 9.5%, depending upon the exact repeating unit structure. (C) 2008 Wiley Periodicals, Inc.