Preparation method of alkyl substitution diphenylmethane diisocyanate

A technology of diphenylmethane and diisocyanate, which is applied in the direction of carbamate preparation, urea preparation, organic chemistry, etc., can solve the difficulty of transportation, storage and use, cannot be popularized and applied in a large range, and the cost of raw materials is expensive To achieve the effect of improving reaction efficiency, improving synthesis reaction process and uncontrollable speed, reducing side reactions and by-products

Inactive Publication Date: 2012-06-27
GUANGZHOU SUPER CHEM COATING CO LTDGUANGZHOU SUPER CHEM COATING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Second, phosgene is very toxic to the human body and pollutes the environment very seriously, so it is difficult to transport, store and use
In fact, the phosgene synthesis of TDI and MDI has a long process route, complex

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0026] The preparation method of the alkyl-substituted diphenylmethane diisocyanate of the present invention mainly comprises the following steps:

[0027] a: Weigh the alkylaniline and urea according to the appropriate proportion and place them in the reactor, the molar ratio of the alkylaniline and urea is 2-2.6:1;

[0028] b: Stir evenly and slowly heat up to 100-200°C, keep stirring for 10-20 minutes after reaching the corresponding temperature, and pass the tail gas into the water for absorption;

[0029] c: Stop the reaction when the reaction changes from red liquid to solid, and cool to room temperature naturally;

[0030] d: washing the solid in step c with alcohol for 3-6 times to obtain dialkyldiphenylurea;

[0031] e: Add dimethyl carbonate to the dialkyl diphenyl urea obtained in step d, and reflux reaction at 110-250°C for 6-12 hours to keep dialkyl diphenyl urea and dimethyl carbonate The molar ratio is 1:4-10;

[0032] f: Add sodium methylate during the reflu...

Embodiment 1

[0041] The preparation method of the diphenylmethane diisocyanate of alkyl substitution comprises the following steps:

[0042] a: Weigh the mixture of methylaniline, propylaniline and butylaniline and urea in the reactor according to the appropriate proportion, and the molar ratio of the mixture of methylaniline, propylaniline and butylaniline to urea is 2:1;

[0043] b: Stir evenly and slowly heat up to 100°C, keep stirring for 10 minutes after reaching the corresponding temperature, and put the tail gas into water for absorption;

[0044] c: Stop the reaction when the reaction changes from red liquid to solid, and cool to room temperature naturally;

[0045]d: washing the solid in step c with methanol for 3 times to obtain dialkyldiphenylurea;

[0046] e: Add dimethyl carbonate to the dialkyl diphenyl urea obtained in step d, and reflux reaction at 110°C for 6 hours, keeping the molar ratio of dialkyl diphenyl urea to dimethyl carbonate as 1:4;

[0047] f: Add sodium met...

Embodiment 2

[0054] The preparation method of the diphenylmethane diisocyanate of alkyl substitution comprises the following steps:

[0055] a: Weigh the mixture of methylaniline, ethylaniline and pentylaniline and urea in the reactor according to the appropriate proportion, and the molar ratio of the mixture of methylaniline, ethylaniline and pentylaniline to urea is 2.6:1;

[0056] b: Stir evenly and slowly heat up to 200°C, keep stirring for 20 minutes after reaching the corresponding temperature, and put the tail gas into water for absorption;

[0057] c: Stop the reaction when the reaction changes from red liquid to solid, and cool to room temperature naturally;

[0058] d: washing the solid in step c with methanol for 6 times to obtain dialkyldiphenylurea;

[0059] e: Add dimethyl carbonate to the dialkyl diphenyl urea obtained in step d, and reflux reaction at 250°C for 12 hours, keeping the molar ratio of dialkyl diphenyl urea to dimethyl carbonate as 1:10;

[0060] f: Add sodiu...

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PUM

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Abstract

The invention discloses a preparation method of alkyl substitution diphenylmethane diisocyanate, which includes the following steps: weighing alkylaniline and urea, placing the alkylaniline and the urea in a reactor, heating the alkylaniline and the urea to the temperature ranging from 100 DEG C to 200 DEG C, stirring the mixture for 10 to 20 minutes, stopping reaction when red liquid is changed to solid, cooling the mixture to the room temperature, washing the mixture for 3 to 6 times through alcohol to obtain dialkyl group diphenyl urea, adding dimethyl carbonate into dialkyl group diphenyl urea, conducting back flowing reaction on the mixture under the temperature ranging from 110 DEG C to 250 DEG C for 6 to 12 hours, adding sodium methoxide into the mixture, conducting filtering after reaction is finished, conducting reduced pressure distillation on filtering liquid, conducting crystallization on normal hexane to obtain alkyl aniline methyl formate, adding lewis acid and methylation agent into the alkyl aniline methyl formate, increasing the temperature to the range from 70 DEG C to 100 DEG C, conducting reaction for 4 to 7 hours, cooling the mixture to the room temperature, conducting filtering on the mixture and washing the mixture through alcohol for 3 to 6 times to obtain alkyl aniline methyl formate and conducting decomposition reaction on the dialkyl group diphenylmethane dicarbamic acid ester. The preparation method of the alkyl substitution diphenylmethane diisocyanate is strong in stability, low in toxicity and controllable in reaction process.

Description

technical field [0001] The invention relates to a preparation method of diphenylmethane diisocyanate, in particular to a preparation method of alkyl-substituted diphenylmethane diisocyanate. Background technique [0002] Isocyanate is one of the raw materials for synthesizing polyurethane resin, which is widely used in civilian and military fields. At present, isocyanate monomers are mainly used in China, toluene diisocyanate (TDI) and diphenylmethylene diisocyanate (MDI), and the preparation method is generally based on the phosgene method. This method is Amino (NH 2 ) into isocyanate groups (NCO). However, there are two major drawbacks in the preparation of TDI and MDI by the phosgene method. One, the activity of phosgene is extremely high, it is difficult to control the stability of its reaction when reacting with other raw materials, and the activity of phosgene can change with the change of its content in the reaction process, when preparing TDI or MDI More by-produ...

Claims

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Application Information

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IPC IPC(8): C07C265/14C07C263/06C07C263/04
Inventor 刘身凯梁剑锋梁秋明李国荣
Owner GUANGZHOU SUPER CHEM COATING CO LTDGUANGZHOU SUPER CHEM COATING CO LTD
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