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Preparation method of methyl acetoacetate

A methyl acetoacetate, methanol technology, applied in the preparation of ketene/polyketene, organic chemistry and other directions, can solve the problems of residual catalyst residue, high rectification requirements, low product content, etc., and achieves reduction of raw material consumption and process operation. Simple and effective for improving rectification yield

Active Publication Date: 2015-02-11
NANTONG ACETIC ACID CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: large investment in equipment and high requirements for rectification
The disadvantage of this process is that the catalyst needs to be removed, there is still residue in the mother liquor purification, the rectification yield is low, and the product content is low
[0007] In summary, the disadvantages of the preparation method of methyl acetoacetate in the prior art are that the equipment investment is large, the rectification requirement is high, the catalyst must be removed, the catalyst removal is not thorough, and the mother liquor purification still has catalyst residues, which affects the stability of the product. Low conversion rate, low rectification yield and low product content

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] A kind of preparation technology of methyl acetoacetate, comprises the following steps:

[0032] Preparation of amine-type ionic liquid catalyst: Add 15.4g (0.21mol) of n-butylamine into a three-necked flask, slowly add 12.0g (0.2mol) of glacial acetic acid dropwise, after the addition is complete, heat to 60°C and continue the reaction for 2 hours to obtain light yellow Liquid n-butylamine acetate, the yield is 96%.

[0033] Esterification process: Add 28.57g of methanol and 0.071g of catalyst n-butylamine acetate ionic liquid into a 500ml three-necked flask, heat up to reflux at 80°C, add 50g of diketene dropwise, dropwise add 50g of diketene, keep it at 120°C for 3h, detect no diketene, and react Finished, the finished product of methyl acetoacetate was distilled out after rectification in a rectifying tower to obtain methyl acetoacetate 68.1, the product yield was 98.7%, and the product content was 99.73%.

Embodiment 2

[0035] Add 26.67g of methanol and 0.077g of catalyst n-butylamine nitrate ionic liquid into a 500ml three-necked flask (refer to Example 1 for catalyst preparation), heat up to reflux, add 50g of diketene dropwise, dropwise add 3h, keep warm at 120°C for 3h, detect no diketene , the reaction is over, and the finished product of methyl acetoacetate is distilled out after rectification in a rectifying tower to obtain 67.8g of methyl acetoacetate, the product yield is 98.2%, and the product content is 99.72%.

Embodiment 3

[0037] Add 24.76g of methanol and 0.67g of ethylamine acetate ionic liquid catalyst (refer to Example 1 for catalyst preparation) into a 500ml three-necked flask, raise the temperature to reflux, add 50g of diketene dropwise, finish the dropwise addition in 3 hours, keep warm at 120°C for 3h, detect no diketene, After the reaction was completed, the finished product of methyl acetoacetate was distilled out after rectification in a rectification tower to obtain 67.9 g of methyl acetoacetate, with a product yield of 98.3% and a product content of 99.76%.

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Abstract

The invention provides a preparation method of methyl acetoacetate. The preparation method sequentially comprises the following steps of: (1) fully dissolving methanol and a catalyst, then adding the mixture into an esterification reaction kettle, heating up, and dropwise adding ketene dimer; (2) after completing dropwise addition, insulating, and cooling to produce crude methyl acetoacetate; (3) rectifying the crude product to obtain the finished methyl acetoacetate. The preparation method is characterized in that the catalyst in the step (1) is an amine type ionic liquid catalyst which is selected from one or more of n-butylamine nitrate, n-butylamine acetate, ethylamine nitrate, ethylamine acetate, propylamine nitrate and propylamine acetate. According to the preparation method of methyl acetoacetate, the amine type ionic liquid catalyst is researched and is good in stability, the stability of methyl acetoacetate is enhanced under the action of the catalyst, the rectification yield of a product can be improved, the technological operations are simple, the raw material consumption is reduced, and the catalyst has obvious advantages and a positive effect.

Description

technical field [0001] The invention belongs to the field of chemical production, in particular to a method for preparing methyl acetoacetate. Background technique [0002] Methyl acetoacetate, colorless liquid, with special odor, easily soluble in water, melting point: -28°C, boiling point: 169-170°C70mmHg(lit.), density: 1.077, refractive index: n20 / D1.419( lit.), flash point: 158°F, solubility: 460g / L (20°C), water solubility: 460g / L (20ºC) [0003] Methyl acetoacetate Uses: (1) Used in the pharmaceutical industry (2) Methyl acetoacetate is used as fungicides hymexazol, pyrimexamol, pyrithrimol, insecticides diazinon, musphos, pyrimidinox , intermediates of the herbicide imazethapyr, the rodenticide coumateral, warfarin, etc. (3) Used as a solvent for cellulose ether and a component of a mixed solvent for cellulose resin, and also used in organic synthesis such as pesticides, medicines, dyes, and polymer stabilizers. [0004] Prior Art Synthetic Process: [0005] The ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/72C07C67/46
Inventor 丁彩峰朱小刚刘芳姚俊生
Owner NANTONG ACETIC ACID CHEM
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