Cyclic keto-butyraldehydes a process for their preparation, and their use in the preparation of cyclic diisocyanates

摘要

New cyclic keto-butyraldehydes of the formula <IMAGE> in which R1 and R2 are either identical or different and denote hydrogen or lower alkyl and in which the cycloaliphatic ring may contain a double bond, can be prepared from the corresponding cyclic keto-olefins in the presence of a rhodium-containing catalyst by reaction with carbon monoxide and hydrogen. The new cyclic keto-butyraldehydes can be used in the preparation of diisocyanates which are used as crosslinking agents in the preparation of polyurethanes.