Vinyl polymerization by lithium Di-n-butylcuprate

Abstract

Lithium di-n-butylcuprate was prepared by the reaction of 1 equiv of cuprous iodide with 2 equiv of n-butyllithium. This reagent was used as a catalyst for polymerization of vinyl monomers and then it was observed that this catalyst was effective to the polymerization of specific monomers such as α,β-unsaturated nitrile, carbonyl, and ester analogues. The polymerization reaction was retarded by the addition of pyridine, nitrobenzene, or hydroquinone. This catalyst exerts a stronger stereoregulating effect on the addition of monomers than n-butyllithium. The polymerization of methyl methacrylate was carried out by using lithium di-n-butylcuprate as a catalyst under various conditions. The effects of catalyst concentration, temperature, polymerization time, and catalyst forming time were examined. It was observed that conversion increased with polymerization time and catalyst concentration. When polymerization temperature was kept at $-10^c C$, the maximum conversion was obtained. The preparation of a catalyst in THF was more rapid than in toluene. From the above results, a coordinated anionic mechanism is proposed.