Bispropylene spiroorthocarbonate

One of the mechanisms taken into consideration for the polymerisation of propylene carbonate was that this proceeded via orthocarbonate species. The likelihood of such a mechanism might be ascertained by the polymerisation of bispropylene spiroorthocarbonate with diethylzinc as the catalyst at 160 °C, which was found to yield poly(propylene ether-carbonate) [143],... 

The polymerisation of the bispropylene spiroorthocarbonate with zinc-based coordination catalysts probably involves zinc alcoholate propagating species, which is shown schematically as follows ... 

Fairly good confirmation of the postulated mechanism of cyclic carbonate enchainment according to scheme (15) may be the obtaining of poly(oxypro-pylene-co-oxycarbonyloxypropylene) of predominant head-to-tail regioregular-ity from bispropylene spiroorthocarbonate with a zinc-based coordination catalyst [146]. It must be emphasised that the copolymerisation of propylene... 

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