Process for preparing dialkyl carbonate and diol products

Dialkyl carbonate and diol products are prepared in an integrated process performed by reacting an alkylene oxide with carbon dioxide in the presence of a non-halide-containing homogeneous carbonation catalyst in a first reaction zone to form a crude cyclic carbonate product. The crude cyclic carbonate product is introduced along with an aliphatic monohydric alcohol to a second reaction zone containing a transesterification catalyst. The transesterification catalyst is comprised of a strongly basic Type I ion exchange resin in gel having a particular form. The cyclic carbonate product and monohydric alcohol are reacted to form the dialkyl carbonate and diol products. In another aspect, dialkyl carbonate and diol products are prepared in an integrated process wherein a halide-containing homogeneous carbonation catalyst is used to form a crude cyclic carbonate product that is then used in a transesterification reaction. The transesterification catalyst is regenerated to accommodate the effects of the halide-containing catalyst.