A PROCESS FOR THE MANUFACTURE OF 4, 4-DISUBSTITUTED 5-METHYLENE-1,3-DIOXOLAN-2-ONES

摘要

A process for the manufacture of 4,4-disubstituted 5-methylene-l,3- dioxolan-2-ones ("cyclocarbonates") of the formula Iwherein Rl and R2 each independently signify a saturated or olefinically- unsaturated aliphatic group or an aromatic group, or Rl and R2 together form tetra- or pentamethylene, by reacting a corresponding 3,3-disubstituted prop-l-yn-3-o1 of the formula HC=C-C(Rl)(R2)-OH (II) with carbon dioxide in the presence of a quaternary ammonium or phosphonium salt as the catalyst comprises using a silver salt as a further catalyst. An alkali metal or quaternary ammonium or phosphonium salt of a carboxylic acid can also be used to increase the catalytic performance of the silver salt catalyst. Moreover, the addition of triphenylphosphine serves to accelerate the reaction to some extent. The silver salts used catalyze this process for the manufacture of cyclocarbonates significantly better than the copper salts previously used for this iurpose. The advantages of the process in accordance with the invention wnlch accrue are the much smaller amounts of catalyst required, significantly shorter reaction times and less drastic reaction conditions for the shorter reaction time. The thus-manufactured cyclocarbonates are valuable intermediates for the production of polymerisates and other useful substances, e.g. dyestuffs and carotenoids.