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Method for preparing methyl acetoacetate by using novel composite catalyst

A technology of methyl acetoacetate and composite catalyst, which is applied in the direction of chemical instruments and methods, preparation of organic compounds, organic compound/hydride/coordination complex catalysts, etc., and can solve the problem of low product yield and crude methyl acetoacetate Low content and other problems, to achieve the effect of reducing energy consumption, easy operation, and improving production capacity

Active Publication Date: 2009-01-07
安徽天成新材料有限公司
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Problems solved by technology

The thick methyl acetoacetate content that this method produces is low (only 97.42%), and product yield is low (only 96.84%)

Method used

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  • Method for preparing methyl acetoacetate by using novel composite catalyst

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specific Embodiment approach

[0008] Add 1.2 tons of methanol with a purity of 99.9% to a 5000L enamel kettle, add 1.5 kg of triethylene diamine under stirring, and dropwise add 3.0 tons of diketene with a content of ≥ 97.5%. After holding at 110-120°C for 1 hour, the temperature is lowered to 40°C. Add 3 kg of concentrated sulfuric acid with a content of ≥98% as a catalyst, keep it for half an hour, and filter the resulting solution to obtain crude diethyl methyl ester.

[0009] The crude diethyl methyl ester is preheated by the diethyl methyl ester steam of the high boiling tower and then enters the low boiling tower to remove the low boilers. About 70% of the methyl acetoacetate in the low boilers is recovered into the rectification tower, where acetic acid, After methanol and other substances are incinerated, carbon dioxide and water are generated, which is pollution-free. The reaction liquid from which low boilers are removed flows by itself into the high boiling tower, the rectification residue is discha...

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Abstract

The invention discloses a method for preparing methyl acetoacetate by using complex catalyst, which comprises the following steps: carrying out esterification reaction of methanol and diketene to generate crude methyl acetoacetate, wherein two different catalysts are added in the different stages of the esterification reaction; triethylenediamine catalyst is added before the esterification reaction; and diketene can be added directly dropwise without being heated by vapor, thereby overcoming the disadvantage that diketene is added dropwise after heating methanol to the boiling point in the conventional process and reducing the energy consumption; and cooling the generated liquid to 40 DEG C after the reaction, adding concentrated sulfur acid catalyst, keeping the temperature for half an hour, filtering, continuously rectifying the filtrate, and separating to obtain fine methyl acetoacetate with the content larger than 99%. Compared with the conventional intermittent rectification method, the continuous rectification method has greatly improved throughput and more convenient operation.

Description

Technical field [0001] The invention relates to a method for preparing methyl acetoacetate using a novel composite catalyst, and belongs to the technical field of chemical industry. Background technique [0002] According to the "Handbook of Fine Organic Chemical Raw Materials and Intermediates" (Chemical Industry Press, edited by Xu Kexun, March 1999), the reaction generation principle of methyl acetoacetate is: That is, use concentrated sulfuric acid as a catalyst, heat the methanol to boiling, then add diketene dropwise, remove the low boiling matter in the reactor, then stop receiving the previous fraction, and start receiving the main fraction, methyl acetoacetate, until it is completely removed. . The crude methyl acetoacetate produced by this method has a low content (only 97.42%) and a low product yield (only 96.84%). Contents of the invention [0003] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a met...

Claims

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Application Information

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IPC IPC(8): C07C69/72C07C67/08B01J31/02B01J27/04
Inventor 陈正荣陈敏陈正崔惠忠
Owner 安徽天成新材料有限公司
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