PREPARATION OF COUMARIN OR AN ALKYLATED COUMARIN AND A CORRES PONDING DIHYDROCOUMARIN

摘要

1390307 Coumarin and dihydrocoumarin or alkylated derivatives thereof STAMICARBON BV 29 Aug 1973 [31 Aug 1972] 40585/73 Heading C2C A process for the preparation of coumarin or an alkylated coumarin together with a corresponding dihydrocoumarin comprises dehydrogenating a lactone of general formula where R 1 to R 6 are the same or different and are hydrogen or C 1 -C 5 alkyl, provided that the total number of carbon atoms in the R groups is not more than 10, with a dehydrogenation catalyst such as palladium or carbon, in the liquid phase, and with the reaction temperature at the start of the dehydrogenation in the range 200‹ to 375‹ C.