Synthesis of six-membered cyclic carbonate monomers by disproportionation of 1,3-bis(alkoxycarbonyloxy)propanes and their polymerization

A new synthetic method of six-membered cyclic carbonates is presented. Diff erent 1,3-bis(alkoxycarbonyloxy)propanes obtained from 1,3-diols and diethy l or dimethyl carbonate were subjected to disproportionation at 200 -350 de grees C in the presence of colloidal silica or Sn(II) stearate leading to 1 ,3-dioxan-2-ones. The disproportionation was carried out in gaseous and liq uid phases. The presented method was especially useful for preparation of s ix-membered mono- and biscyclic carbonates from polyfunctional alcohols suc h as trimethylolpropane, pentaerythritol and trimethylpropane dimer. The st ructure of the polymers obtained from 5-methyl-1,3-dioxan-2-one and 5-ethyl -5methoxycarbonyloxymethyl-1,3-dioxan-2-one in the presence of different ca talysts were analyzed using MALDI-TOF mass spectrometry.