Chloromethyloxirane Epichlorohydrin, ECH

High molecular weight polyECH as well as its copolymers with ethylene oxide (EO) are commercial products. Their production is based on the discovery made by Van-denberg4 5 who first observed that some modified alkyl aluminiums are efficient initiators, giving high molecular weight products in the polymerization of various oxiranes. 

Although sometimes it is not clear whether the actual propagation should be classified as anionic or cationic (for instance, for propylene oxide)9) and sometimes it is assumed that both mechanisms simultaneously operate, it is quite apparent that ECH polymerizes with these initiators exclusively by a cationic mechanism. 

This basic procedure may be modified to obtain either rubbery atactic or crystalline isotactic polyECH as the main product. 

The industrial process for making ECH elastomers (Herclor of Hercules Co. and Hydrin of B. F. Goodrich Chemical Co.) were developed 12) by the use of alkylaluminum initiators. 

The information concerning these processes is mostly from the patent literature 13). In our description we mainly relied on the review article by Vandenberg12). 

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