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Preparation method of alpha-cyanacrylate

A technology of cyanoacrylate and cyanoacetate, which is applied in the field of preparation of α-cyanoacrylate, can solve the problems of waste energy treatment, complex process, environmental pollution, etc., and achieve production cost saving, process safety, The effect of broad application prospects

Inactive Publication Date: 2008-01-02
北京科化新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The shortcoming of above-mentioned known technology is that when carrying out condensation reaction, dehydration operation mostly is carried out in toxic and flammable organic solvents such as methyl alcohol, benzene and dichloroethane; In whole reaction process, added a certain amount of plasticizer
If organic solvents are used in the production process, there are many disadvantages, such as: unsafe, environmental pollution, complicated process, waste of energy and troublesome disposal, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 1. Applied to the preparation of ethyl α-cyanoacrylate

[0019] (1). Mix ethyl cyanoacetate and paraformaldehyde in a reaction kettle, in the presence of a hexahydropyridine catalyst, at a temperature of 60±5°C and a reaction start of 15-25mmHg, and a vacuum of 1-3mmHg at the end of the reaction Condensation reaction under low temperature, after dehydration is complete, add phosphorus pentoxide and hydroquinone polymerization inhibitor, and then carry out cracking distillation under the condition of vacuum with a vacuum degree of 1-5mmHg and a temperature of 160-195°C;

[0020] Among them, the molar ratio of ethyl cyanoacetate to paraformaldehyde is 1.07-1.00; the addition amount of phosphorus pentoxide is 4-8 g / mol paraformaldehyde, and the addition amount of hydroquinone is 1-3 g / mol Paraformaldehyde; the addition amount of hexahydropyridine is 3ml / mol paraformaldehyde.

[0021] (2). The crude monomer of α-cyanoacrylate ethyl ester obtained in step (1) is rectified a...

Embodiment 2

[0023] 2. Applied to the preparation of methoxyethyl α-cyanoacrylate

[0024] (1). Mix methoxyethyl cyanoacetate and paraformaldehyde in a reaction kettle, in the presence of a hexahydropyridine catalyst, at a temperature of 60±5°C and a reaction start of 30mmHg, and a vacuum of 1mmHg at the end of the reaction Carry out condensation reaction, add phosphorus pentoxide and hydroquinone polymerization inhibitor after dehydration is complete, and then carry out cracking distillation under the conditions of vacuum with a vacuum degree of 0.1-25mmHg and a temperature of 160-200°C;

[0025] Wherein, the feeding molar ratio of methoxyethyl cyanoacetate and paraformaldehyde is 1.05~1.00; the addition amount of phosphorus pentoxide is 4~8g / mol paraformaldehyde, the addition amount of hydroquinone is 1~ 3g / mol paraformaldehyde; the addition amount of hexahydropyridine is 3ml / mol paraformaldehyde.

[0026] (2). The crude monomer of α-cyanoacrylate ethyl ester obtained in step (1) is rec...

Embodiment 3

[0028] (1). Methyl cyanoacetate and formaldehyde aqueous solution are mixed in a reaction kettle, and in the presence of a sodium hydroxide catalyst, at a temperature of 60°C, the reaction starts at 45mmHg, and the reaction ends at 0.5mmHg for condensation reaction under vacuum; dehydration After completion, add phosphorus pentoxide, catechol and p-tert-butylphenol polymerization inhibitor, and then carry out pyrolysis and distillation under the conditions of a vacuum with a vacuum degree of 0.5-25mmHg and a temperature of 165-210°C;

[0029] Wherein, the feeding molar ratio of methyl cyanoacetate and formaldehyde is 1.10: 1.00; ; The addition of sodium hydroxide is 1.0 gram / mol formaldehyde

[0030] (2). The crude monomer of α-methyl cyanoacrylate obtained in step (1) is then rectified to obtain the relatively high α-methyl cyanoacrylate with a yield of 60% and a purity of 99%. fine monomer.

[0031] In order to increase the storage stability of the product, sulfur dioxide ...

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PUM

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Abstract

The invention discloses a condensation reaction without anhydrating agent and the preparing method of alpha-cyanacrylate without elasticizer in the alpha-cyanacrylate field. The method comprises the following steps: regarding cyanoacetate and methyl aldehyde solution or cavaform as the material; proceeding with the condensation reaction without anhydrating agent in the basic catalyst, 60+ -5Deg. C, 0.5-50mmHg vacuum condition; adding the inhibitor after completing dewatering; proceeding with cracking distillation without elasticizer at 0.5-25mmHg vacuum and 160-220Deg. C; getting high purity and production efficient alpha-cyanacrylate by distillation. The invention doesn't pollute the environment, which is provided with the wide application foreground and the apparent economy benefit.

Description

technical field [0001] The invention belongs to the field of preparing α-cyanoacrylate, in particular to a condensation reaction without dehydrating agent and a preparation method of α-cyanoacrylate without plasticizer. Background technique [0002] U.S. Patents 3254111, 3639361, 3577394, and Chinese Patent Publication Nos. CN87103468, CN1261070, CN1070636, and CN1047077 all disclose the synthesis process or method for preparing α-cyanoacrylate (mainly α-alkyl cyanoacrylate). The main production process or method disclosed by these patents is: alkyl cyanoacetate (commonly used ethyl cyanoacetate, butyl cyanoacetate, etc. depending on different product series) in aqueous formaldehyde or with paraformaldehyde After mixing, condensation reaction is carried out in the presence of alkaline catalyst (usually hexahydropyridine, sodium hydroxide, sodium alkoxide, etc.) and dehydrating agent, and the dehydrating agent is recovered after dehydration. Cracking distillation is carried ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C255/23C07C253/30
Inventor 袁有学任惠敏李琦冉建新
Owner 北京科化新材料科技有限公司
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