HIGH CATALYTIC ACTIVITY OF CALCINED IRON SULFATE FOR POLYMERIZATION OF ISOBUTYL VINYL ETHER

Isobutyl vinyl ether is known to be polymerized by a cation catalyst such as metal oxide-HCl. Several metal oxides catalyze the polymerization at the temperature around the boiling point of monomer. The authors have found that calcined iron sulfate is exceedingly active for this polymerization, and the crystalline polymer was synthesized with this catalyst at room temperature. In the reported experiments, the iron(II) sulfate catalyst was prepared by calcining a guaranteed reagent grade hydrate in a pyrex glass or quartz tube for 3 hr in air and stored in ampoules. When the catalyst (0. 1 g), heat-treated at 700 degree C, was added to 2 ml of isobutyl vinyl ether (guaranteed reagent grade containing 0. 003% of p-tert-butyl catechol as stabilizing agent) at room temperature, polymerization occurred immediately with violent evolution of heat. The reaction was complete in less than 10 sec. The time required for the formation of the polymer depends on the calcination temperature of iron sulfate; the catalyst calcined at 700 degree C proved to be the most active. However, the catalyst calcined at 750 degree C was inactive at all in spite of the remarkable activity when heat-treated at 700 degree C. The catalysts prepared by calcining at 800 and 900 degree C were also inactive.