Polymers of carbonic acid, 6. Polymerization of trimethylene carbonate (1,3‐dioxan‐2‐one) with complexation catalysts

Abstract

AbstractNumerous bulk polymerizations of trimethylene carbonate (1,3‐dioxan‐2‐one, 2) were conducted at 90, 120 and 150°C. Tributyltin methoxide, tributyltin acetate, dibutyltin dibromide, tin(II) 2‐ethylhexanotate, bismuth(III) 2‐ethylhexanoate and zinc stearate were used as initiators. On the basis of GPC measurements with universal calibration, weight‐average molecular weights up to approx. 22000 were found. The chemical structure of the resulting polycarbonates was examined by elemental analyses and 1H NMR spectroscopy. In contrast to similar polymerizations of ethylene carbonate, either groups were never found. However, all polycarbonates contain a CH2OH end‐group. Furthermore, methylcarbonate, acetate, 2‐ethylhexanoate or stearate end‐groups were found. Cyclic oligomers were not detectable in the gel‐permeation chromatograms of reaction mixtures. IR spectra indicate complexation of the carbonyl group by the initiators. The reaction mechanism is discussed.