Abstract: Immobilized Lewis Acid catalyst comprising porous polymer film substrate having at least one Lewis Acid immobilized on pore surfaces thereof, said polymer film substrate prior to having said Lewis Acid immobilized thereon comprising a porous film of functionalized polymer and, optionally, unfunctionalized polymer, said functionalized polymer having within its structure units represented by the formula ##STR1## and said unfunctionalized polymer having within its structure repeating monomer units represented by the formula ##STR2## wherein D represents OH, halide, NH.sub.2, NHR.sup.3, OM', or OM";R.sup.1 represents hydrogen, C.sub.1 -C.sub.24 alkyl, C.sub.3 -C.sub.24 cycloalkyl, C.sub.6 -C.sub.18 aryl or C.sub.7 -C.sub.30 alkylaryl;R.sup.2 represents C.sub.3 -C.sub.24 alkyl, C.sub.3 -C.sub.24 cycloalkyl, C.sub.6 -C.sub.18 aryl or C.sub.7 -C.sub.30 alkaryl;R.sup.3 represents C.sub.1 -C.sub.24 alkyl, C.sub.3 -C.sub.24 cycloalkyl, C.sub.6 -C.sub.18 aryl or C.sub.7 -C.sub.

Abstract: A multi-step membrane separation process whereby the natural polymer .alpha.-chitosan extracted from the shell of crustaceans, etc. can be simply separated and purified into low molecular weight chitosan or oligosaccharide chitosan in a high yield. A chitosan mixture of various molecular weights is reacted with an acid in the presence of enzyme while applying an ultrasonic treatment to the mixture and then, added with pure water to give an aqueous solution having a chitosan concentration of 1 to 50%. It is subjected to a continuous membrane filtration under a pressure and further to a second fractionation and separation technique employing a proper membrane according to a desired molecular weight cut-off, at least one time.

Abstract: An immobilized Lewis Acid catalyst system for the carbocationic polymerization of olefin monomer is provided. The catalyst comprises a porous polymer support having catalytically active Lewis Acid residue bonded to the surface of the support including the pore surfaces.