Dimethyloxirane 2,3-Epoxybutane

Polymerization initiated with BF3 0(C2H5)2 or (C2H5)30 A8 (A = SbClf or BF4 9) gave only the ohgomer fraction with 60—90 % yield. 

Linear polymers with fairly high molecular weights (ninh = 0.6 for 0.5% solution in benzene at 30 °C) were also obtained in the polymerization of 1,1,2-trimethyl-oxirane (2,3-epoxy-2-methylbutane) with R3A1-H20 initiator 16). 

The other two highly substituted a-epoxides which polymerize to high polymers are cis- and trans-l,4-dichloroepoxybutanes, (cD and tD, respectively)12)  

These polymers, developed by Vandenberg, are the natural extension of the successful development of two other chlorinated polyethers , namely poly-3,3-bis-(chloromethyl)oxetane (polyBCMO, Penton of Hercules Co) and the previously mentioned epichlorohydrin elastomers. The presence of two bulky chloromethyl groups hampers cyclization and increases the stability of the cationic active centers. 

These monomers (a mixture of cis- and trans-isomers) may be obtained according to the following scheme  

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Mahmoudian et al. have tested 18 organisms that use ethene or propene as the carbon source, including Aerococcus, Alcaligenes, Micrococcus, and Staphylococcus spp., in the epoxidation of short-chain aliphatic olefins, and all of them stereospecifically produce (P)-l,2-epoxypropane (3, 90-96% ee), (R)-l,2-epoxybutane (4, 90-98% ee), and 2R, 3R)-2,3-dimethyloxirane (6, 64-88% ee) from the corresponding olefins (Scheme 13.1) [75]. Other alkene-utilizing bacteria from the genus of Nocardia, Xunthobacter, Mycobacterium, etc. have also been used in the production of 3,4, and 8 with up to 98% ee (Scheme 13.1) [76, 77]. 

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