SEPARATION OF BENZENE CYCLOHEXANE MIXTURE S BY DIMETHYLAMINOETHYL METHACRYLATE GEL MEMBRANES FORMED IN PORES OF A THIN SILICA MEMBRANE

Dimethylaminoethyl methacrylate gels were synthesized by crosslinking with ethylene glycol dimethacrylate (EGDMA), diethylene glycol dimetha crylate (DEGDMA), or triethylene glycol dimethacrylate (TEGDMA). They swell in aromatic solvents but hardly at all in paraffinic solvents. T he gels were formed in the pores of thin silica membranes. The composi te membranes were used for separation of benzene/cyclohexane mixtures by the pervaporation method. As expected from the swelling-shrinking b ehavior of the gels in benzene/cyclohexane mixtures, benzene permeated selectively through the membranes. The selectivity depended on the le ngth of the crosslinking agents used for synthesizing the gels, and in creased in this order: EGDMA > TEGDMA> DEGDMA. Furthermore, the swelli ng-shrinking behavior in benzene/cyclohexane mixtures depended on temp erature, because of the heat-sensitive property of gels, and even in c yclohexane, the swelling of gels was clearly noticed with increasing t emperature. Thus the selectivity of composite membranes lowered with i ncreasing the separation temperature.