Kinetic Studies of the Solution Polymerization of Trioxane Catalyzed by BF3·O(C2H5)2. IV. The Change in the Formaldehyde Concentration during Polymerization

Abstract

Abstract In the solution polymerization of trioxane catalyzed by BF3·O(C2H5)2 and boron fluoride, the dependence of the yield of CH2O produced in the induction period on the polymerization conditions has been studied at 30°C. In the case of the BF3·O(C2H5)2 catalyst, the formation of CH2O has been recognized in n-hexane just after the addition of the catalyst while no induction period of the polymerization was seen. In polar solvents, both the formation of CH2O and the polymerization were retarded as the water concentration increased. In these systems the concentration of the CH2O formed changed with time, and no equilibrium or stationary concentration was recognized. In the case of the boron fluoride catalyst, an increase in the water concentration remarkably increased the induction period, also. For either catalyst the induction period was not decreased by the addition of CH2O to the polymerization system in advance of the catalyst addition. Therefore, it has been deduced that, in the polymerization system catalyzed by BF3·O(C2H5)2, the polymerization and depolymerization reaction took place simultaneously and that the induction period was caused by water, which inhibits the formation of high polymers.