| 摘要 |
A method for the production of 2-coumarone or substituted 2-coumarones is disclosed, wherein cyclohexanone or substituted cyclohexanone is reacted with a carboxyl-containing acylating agent, (a) to give C1-C3-alkyl 2-(2-oxo-cyclohexyl)-2-hydroxyacetate or substituted C1-C3-alkyl 2-(2-oxo-cyclohexyl)-2-hydroxyacetates, which are either (a1) directly converted to 2-coumarone or substituted 2-coumarones by means of catalytic gas-phase dehydrogenation, or (a2) dehydrated by means of azeotropic distillation under basic conditions, or by use of a strong acid, or a strongly acidic ion exchanger to a mixture of substituted C1-C3-alkyl 2-oxocyclohexylidenacetate and the enol-lactone of the 2-oxocyclohexylidenacetic acid, or a mixture of substituted C1-C3-alkyl 2-oxocyclohexylidenacetate and the enol-lactone of the substituted 2-oxocyclohexylidenacetic acid, which is finally converted in turn by catalytic gas-phase dehydrogenation to 2-coumarone, or substituted 2-coumarones, or (b) are directly converted under acidic or basic conditions into a mixture of C1-C3-alkyl 2-oxocyclohexylidenacetate and the enol-lactone of 2-oxo-cyclohexylidenacetic acid, or a mixture of substituted C1-C3-alkyl 2-oxocyclohexylidenacetate and the enol-lactone of the substituted 2-oxo-cyclohexylidenacetic acid, which is finally converted in turn by catalytic gas-phase dehydrogenation into 2-coumarone or substituted 2-coumarones. |
