| abstract |
An anion exchange method conducted at a high temperature, which comprises using a crosslinked anion exchanger which comprises structural units having a quaternary ammonium group of the following formula (a) and structural units derived from an unsaturated hydrocarbon group-containing crosslinkable monomer, and of which at least 90% of anion exchange groups are present in the form of a group represented by <IMAGE> as defined in the following formula (a): <IMAGE> (a) wherein R is a -(CH2)n-group (n=an integer of from 3 to 18) which may include a cyclic hydrocarbon, each of R1, R2 and R3 which are independent from one another, is a C1-C8 hydrocarbon group or a C1-C8 alkanol group, the benzene ring of the formula (a) may be substituted by an alkyl group or a halogen atom, or may be condensed with other aromatic ring, and X is an anion. |