MECHANISM OF RECYCLIZATION OF FURANS TO THIOPHENES AND SELENOPHENES UNDER ACID CATALYSIS. 1. KINETIC STUDIES OF THE REACTION OF 2,5-DIALKYLFURANS WITH HYDROGEN SULFIDE IN THE PRESENCE OF HYDROCHLORID ACID

Article abstract of DOI:10.1007/BF00470688

The transformation of 2,5-dialkylfurans to thiophene by reaction with hydrogen sulfide in the presence of hydrochloric acid was studied.The reaction was found to be first order with respect to the furan; the rate of consumption of the furan did not change with the increasing length of one of the alkyl substituents.Recrystalization in the presence of acid proceeds in two independent directions: through the formation of an intermediate dicarbonyl compound, and by direct conversion of the furan to a thiophene.Kinetic data showed that the reaction occurs mainly by the second route.