Thermally induced polymerization in m- and p-halogenomethyl-benzoates to poly(hydroxymethylbenzoic acid)

Heating alkali sails of m- and p-halogenomethylbenzoic acid above ca. 100 d egrees C leads to elimination of alkali halide and formation of the corresp onding poly(hydroxymethylbenzoic acid). The salt is precipitated as small c ubes (ca. 0.3 mu m) in a matrix of the polyester and can be washed out with water to leave a porous material (pore size <1 mu m) The degree of polymer isation of the polymers is between 30 and 100, depending on the benzoate sa lt and the reaction conditions. The reaction appears to occur at least part ially in the solid state.