Preparation of beta-dione

Abstract

The invention relates to a preparation method of beta-diketone; Claisen condensation reaction is adopted; the chemical general expression of the beta-diketone is R1COCH2COR2, wherein, R1 is C6-C12 alkyl, and R2 is phenyl or alkylphenyl; the method comprises the following steps: ester, phenyl ketone and partial solvent are pre-mixed for spare; a condensating agent and remaining solvent are added in a reactor, and the temperature is raised under nitrogen atmosphere; during the period when the temperature of the reactor is raised to the needed temperature of the condensation reaction, the pre-mixed material is dropwise added in the reactor for carrying out the condensation reaction with a system which is composed of the condensating agent and the remaining solvent under an infinite reflux condition; after the pre-mixed material is dropwise added, heat-preserving condensation reaction is carried out continuously under the infinite reflux condition. The ester and the condensating agent in the raw material are contacted when the reacting condition is achieved, and acylation reaction is slow reaction, relative to the Claisen condensation reaction, thus being capable of better solving the acidylation problem of the ester, and reducing the effect of the acylation reaction to the minimum; the yield of the beta-diketone is more than or equal to 90 percent.

Description

technical field [0001] The present invention relates to condensed acyclic or carbocyclic compounds, in particular to a preparation method of β-diketone. Background technique [0002] The extraction performance of β-diketones showed that it is an effective copper extractant. When preparing β-diketone compounds, the Claisen condensation reaction is usually adopted, and the synthesis is carried out under the catalytic action of a condensing agent. For example, ester, inert hydrocarbon solvent and condensing agent are first added to the reactor, and the ketone or its derivatives are added dropwise during the period when the temperature is raised to the temperature required for the condensation reaction. Chinese invention patent CN1046498C announced a kind of "improved method for preparing β-diketone", which includes the following steps: [0003] (A) reacting acetophenone and an ester in the presence of a basic catalyst in an inert hydrocarbon solvent at the reflux temperature ...

AI Technical Summary

Problems solved by technology

[0013] The above method also has the following defects: in the process of raising the temperature, part of the ester and the condensing agent produce acylation, which changes the proportion of the original material, resulting in a decrease in the yield