Process for preparing thiophenes
AssigneeSociete Nationale Elf Aquitaine (Production)
InventorsJoel Barrault, Michel Guisnet, Jacques Lucien, Raymond Maurel
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Abstract
Preparation of a thiophene by the action of H.sub.2 S on an organic substance containing oxygen or sulphur. The substance which is used is an unsaturated carbonyl or thiocarbonyl compound, particularly an aldehyde, thioaldehyde, ketone or thioketone. The reaction preferably takes place between 250.degree. and 500.degree. C. on a catalyst of the alumina type containing an alkali or alkaline earth oxide. The process permits the unsubstituted or substituted thiophene to be obtained with high yields and high degrees of selectivity, exceeding 70%.
Claims15
A method for preparing thiophenes, which comprises reacting in the presence of an alumina catalyst between 250.degree. and 500.degree. C. hydrogen sulfide with a compound selected from the group consisting of the unsaturated carbonyl and thiocarbonyl compounds represented by the formula ##STR11## where X is O or S while each of the symbols R, R', R" and R''' is hydrogen or lower alkyl, or ortho-tolualdehyde or phenyl-acetaldehyde, then condensing the reaction mixture and separating the thiophene formed.
Dependencies are inferred from the claim text.