Process for manufacturing cyclocarbonates using a silver salt catalyst

Abstract

A process for the manufacture of 4,4-disubstituted 5-methylene-1,3-dioxolan-2-ones ('cyclocarbonates') of the formula: ##STR1## wherein R.sup.1 and R.sup.2 each independently signify a saturated or olefinically-unsaturated aliphatic group or an aromatic group, or R.sup.1 and R.sup.2 together form tetra- or pentamethylene, by reacting a corresponding 3,3-disubstituted prop-1-yn-3-ol of the formula HC.tbd.C--C(R.sup.1)(R.sup.2)--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 catalyze this process significantly better than the previously utilized copper salts. Advantageously, the process uses much smaller amounts of catalyst, significantly shortens reaction times, and mandates less drastic reaction conditions. Cyclocarbonates produced by this process are valuable intermediates for the production of polymerizates and other useful substances, such as dyestuffs and carotenoids.