Method for preparing methyl acetoacetate

Abstract

The invention discloses a method for preparing methyl acetoacetate. The method comprises the following steps: adding a catalyst once, continuously adding ketene dimer and a methanol solution through a raw material feeding hole, continuously adding an extraction agent through an extraction agent feeding hole, simultaneously adding two materials into a reaction-extraction rectifying tower, and starting heating; carrying out total reflux so as to obtain the methanol solution through the tower top of the reaction-extraction rectifying tower and obtain a mixed liquid of the methyl acetoacetate, the catalyst and the extraction agent through the tower bottom of the reaction-extraction rectifying tower, and enabling the mixed liquid to flow into a decompression extraction tower from a tower-bottom discharging hole, so as to obtain a target product, namely the methyl acetoacetate from the tower top of the decompression extraction tower. Due to the arrangement of the reaction-extraction rectifying tower and the decompression extraction tower, the methyl acetoacetate is prepared by virtue of a reaction-rectification and extraction-separation integrated reaction, the materials are fed once, and the catalyst and the extraction agent can be recycled, so that the operation is simple, the cost is lowered, the purity and rate of the prepared methyl acetoacetate are high, and the energy consumption is reduced.

Description

technical field [0001] The invention relates to a method for preparing methyl acetoacetate. Background technique [0002] Methyl acetoacetate is an important raw material for the synthesis of "three medicines". It is used as a raw material for pesticides to prepare insecticides, such as "diazinon", "allethrin", "monocrotophos", etc., and to prepare herbicides, such as " Herbicide, etc., and fungicides; used as raw materials for dyes to produce pyrazolone series and aniline derivatives series dyes; used as solvents for the dissolution of cellulose ethers, antimalarials, spices, lacquers and coatings; As a chelating agent, a resin modifier, and a tackifier for printing inks; as a polymerization catalyst to prepare metal complexes such as aluminum and chromium; also as a hydrophobic agent. [0003] There are two traditional production methods of methyl acetoacetate: using diketene and methanol as raw materials, using tertiary amines (boiling point around 280°C) as catalysts, d...

AI Technical Summary

Problems solved by technology

The above method is because the reaction process is a gap reaction, the conversion rate is 61%, and the product purity is 98%, the catalyst cannot be recycled, resulting in an increase in cost, and the purification process is complicated and the production efficiency is low

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