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Post-treatment method for continuously synthesizing methyl 4-chloroacetoacetate

A technology of methyl acetate and chloroacetyl, which is applied in the post-treatment field of continuous synthesis of methyl 4-chloroacetoacetate, can solve problems such as poor product quality, environmental pollution, and difficult product separation, and achieve product yield and quality improvement, Inhibit the deep chlorination of products and ensure the effect of product quality

Active Publication Date: 2018-04-17
NANTONG ACETIC ACID CHEM +1
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0009] In order to solve the above problems, the object of the present invention is to provide a post-processing method for continuously synthesizing methyl 4-chloroacetoacetate, to solve the problem that the amount of waste water is relatively large in the current methyl 4-chloroacetoacetate synthesis process, and waste salt is difficult to handle. The environmental pollution is serious, and the product separation is difficult, the rectification yield is low, and the product quality is poor, etc.

Method used

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  • Post-treatment method for continuously synthesizing methyl 4-chloroacetoacetate

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Embodiment 1

[0040] Embodiment 1: a kind of post-processing method of continuous synthesis of methyl 4-chloroacetoacetate:

[0041] 1) Using diketene, chlorine gas, dichloromethane and methanol as raw materials, first dissolve chlorine gas in dichloromethane, and enter the chlorination reaction module of the microchannel continuous flow reactor through a metering pump together with diketene, and then enter into the esterification reaction with methanol The module synthesizes methyl 4-chloroacetoacetate, and the HCl tail gas generated in the process is connected to the three-stage HCL absorption system, and the water absorption range of each stage is m (water absorption of each stage): m (diketene) = 1.5: 1;

[0042] 2) After the esterification reaction, the dichloromethane solution of methyl 4-chloroacetoacetate is obtained, which is added to the washing layered tower, and the amount of washing in the washing layered tower is the same as that of the three-stage HCL. 7. After washing with w...

Embodiment 2

[0047] Embodiment 2: a kind of aftertreatment method of continuous synthesis 4-methyl chloroacetoacetate:

[0048] 1) Step 1) is the same as in Example 1, the water absorption range of each stage is m (absorbed water amount of each stage): m (diketene)=1.7:1;

[0049] 2) After the esterification reaction, the dichloromethane solution of methyl 4-chloroacetoacetate is obtained, which is added to the washing layered tower, and the amount of washing in the washing layered tower is the same as that of the three-stage HCL. 7.5. After washing with water, the water phase goes to the three-stage HCL absorption system, and the organic phase enters the lightening distillation tower;

[0050] 3) The organic phase is preheated to 38°C by the preheater and fed continuously from the light-removing rectification tower. In the top receiving tank, the water is separated through the water separator (the separated water enters the HCL absorption system), and after the water content of the dichl...

Embodiment 3

[0054] Embodiment 3: a kind of aftertreatment method of continuous synthesis 4-methyl chloroacetoacetate:

[0055] 1) Step 1) is the same as in Example 1, the range of water absorption per stage is m (water absorption per stage): m (diketene) = 2:1;

[0056] 2) After the esterification reaction, the dichloromethane solution of methyl 4-chloroacetoacetate is obtained, which is added to the washing layered tower, and the amount of washing in the washing layered tower is the same as that of the three-stage HCL. 8. After washing with water, the water phase goes to the three-stage HCL absorption system, and the organic phase enters the light removal distillation tower;

[0057] 3) The organic phase is preheated to 40°C by the preheater and continuously fed from the light-removing rectification tower. In the receiving tank, the water is separated by a water separator (the separated water enters the HCL absorption system), and after the water content of the dichloromethane reaches 0...

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Abstract

The invention belongs to the field of chemical engineering and in particular relates to a post-treatment method for continuously synthesizing methyl 4-chloroacetoacetate. The post-treatment method comprises the following steps: taking diketene, chlorine gas, dichloromethane and methanol as raw materials; inoculating HCl tail gas generated in a process of synthesizing the methyl 4-chloroacetoacetate into a three-grade HCl absorption system; carrying out esterification reaction to obtain a dichloromethane solution of the methyl 4-chloroacetoacetate; adding the dichloromethane solution into a water-washing layering tower; after carrying out water washing, removing the three-grade HCl absorption system from a water phase; after conveying an organic phase into a light component rectifying tower, continuously feeding the organic phase into a negative-pressure rectifying tower from a tower kettle through a feeding pump, so as to obtain a methyl 4-chloroacetoacetate finished product. A byproduct of the HCl absorption system is 25 to 30 percent industrial hydrochloric acid and can be used for selling. The light component rectifying tower and a decompression rectifying tower are used for continuously rectifying and separating a solvent and the product; the solvent can be recycled and applied; a separation technology is green and environmentally friendly and the rectifying efficiency is greatly improved.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a post-treatment method for continuously synthesizing methyl 4-chloroacetoacetate. Background technique [0002] Methyl 4-chloroacetoacetate is a colorless light yellow liquid, molecular weight: 150.56, melting point: 14-16°C, boiling point: 212°C, density: 1.287, flash point: 107°C, water solubility: 71g / L (20°C ). Methyl 4-chloroacetoacetate is a good intermediate for pharmaceutical synthesis. It is mainly used to produce oxiracetam. Oxiracetam belongs to the drug for the treatment of cerebrovascular diseases. It is the fourth generation of nootropic drugs and pyrrolidones. Derivatives, the trade names are Jianlangxing, Ou Laining, neuromet and neupan, etc. Oxiracetam is a new type of central nervous system drug, which can promote the functional recovery of nerve cells and improve brain metabolism. It has multiple functions, has significant curative effect on tre...

Claims

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Application Information

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IPC IPC(8): C07C67/46C07C67/54C07C67/58C07C67/56C07C69/716C01B7/07
CPCC01B7/0706C07C67/46C07C67/54C07C67/56C07C67/58C07C69/716
Inventor 庆九俞新南薛金全朱小刚刘芳卢乐朱爱华
Owner NANTONG ACETIC ACID CHEM
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