Process for preparing dialkyl carbonate and diol products

摘要

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.

主权项

1. A method of preparing a dialkyl carbonate and diol products in an integrated process comprising:
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; and introducing the crude cyclic carbonate product from the first reaction zone along with an aliphatic monohydric alcohol to a second reaction zone containing a transesterification catalyst comprised of a strongly basic Type I ion exchange resin in gel form of polystyrene crosslinked with divinyl benzene having from about 4% to about 8% crosslinking, and from about 40% to about 60% water retention, the ion exchange resin including at least one of quaternary ammonium groups or quaternary phosphonium groups, the transesterification catalyst being configured as substantially spherical beads having a particle size of from about 0.2 mm to about 1.5 mm and allowing the cyclic carbonate product and monohydric alcohol to react under reaction conditions to form the dialkyl carbonate and diol products wherein the non-halide-containing homogeneous carbonation catalyst comprises inorganic compounds selected from the group consisting of hydroxides, carbonates, and bicarbonates of alkali metals, or organic compounds selected from the group consisting of alkali methoxides and alkali ethoxides.