Coordinate polymerization of heterocycles: 3. Oligomerization of tetrahydrofuran induced by TiCl 4 in the presence of acetyl chloride and epichlorohydrin

Abstract

When a strong and a weak donor are present as promotors in the oligomerization of tetrahydrofuran then under certain conditions a pronounced stabilization of active centres occurs. The formation of centres is governed by equilibrium reactions during which the monomer and promotors are coordinated to Ti atom. The coordination ability is determined by the donor numbers. The dependence of oligomerization reaction rate on the molar fraction of tetrahydrofuran exhibits a minimum. At the concentration conditions corresponding to this minimum, especially in the presence of diethyl ether, the active centres do not lose their reactivity and the oligomerization becomes stationary to high conversions. The results suggest that the classification of coordinate polymerizations to cationic and anionic coordinate polymerizations is meaningless. Coordinate polymerizations belong to a separate group of polyreactions similarly as e.g. radical polymerizations.