申请人:——
公开号:US20030171601A1
公开(公告)日:2003-09-11
The invention relates to a method for the production of 2-coumarone or substituted 2-coumarones, whereby cyclohexanone or substituted cyclohexanone is reacted with a carboxyl-containing acylating agent a) to give methyl 2-(2-oxo-cyclohexyl)-2-hydroxyacetate or substituted methyl 2-(2-oxo-cyclohexyl)-2-hydroxyacetates, which are either a
1
) directly converted to 2-coumarone or substituted 2-coumarones by means of catalytic gas-phase dehydrogenation, or a
2
) 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 methyl 2-oxocyclohexylidenacetate and the enol-lactone of the 2-oxocyclohexylidenacetic acid, or a mixture of substituted methyl 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 methyl 2-oxocyclohexylidenacetate and the enol-lactone of 2-oxo-cyclohexylidenacetic acid, or a mixture of substituted methyl 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.
该发明涉及一种生产2-香豆酮或取代2-香豆酮的方法,其中环己酮或取代环己酮与含羧基的酰化试剂a) 反应,得到甲基2-(2-氧代环己基)-2-羟基乙酸酯或取代甲基2-(2-氧代环己基)-2-羟基乙酸酯,这些化合物要么a1) 直接通过催化气相脱氢转化为2-香豆酮或取代2-香豆酮,要么a2) 在碱性条件下通过共沸蒸馏脱水,或使用强酸,或强酸性离子交换剂将其转化为甲基2-氧代环己基亚乙酸酯和2-氧代环己基亚乙酸的烯醇内酯的混合物,或取代甲基2-氧代环己基亚乙酸酯和取代2-氧代环己基亚乙酸的烯醇内酯的混合物,最终再通过催化气相脱氢转化为2-香豆酮或取代2-香豆酮,或b) 直接在酸性或碱性条件下转化为甲基2-氧代环己基亚乙酸酯和2-氧代环己基亚乙酸的烯醇内酯的混合物,或取代甲基2-氧代环己基亚乙酸酯和取代2-氧代环己基亚乙酸的烯醇内酯的混合物,最终再通过催化气相脱氢转化为2-香豆酮或取代2-香豆酮。