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Preparation method of 3,3'-dimethyl-4,4'-diamino dibenzyl methane

A technology of diaminodiphenylmethane and dimethyl, which is applied in 3 fields, can solve the problems of high cost, many reaction by-products, and low yield, and achieve the effects of simple operation, low cost, and high yield

Inactive Publication Date: 2007-04-18
SHANGHAI CHEM REAGENT RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a kind of 3,3'-dimethyl-4, the preparation method of 4'-diaminodiphenylmethane, to overcome the many reaction by-products in the prior art, the yield is low; Raw material price is expensive, High cost and cumbersome operation

Method used

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  • Preparation method of 3,3'-dimethyl-4,4'-diamino dibenzyl methane
  • Preparation method of 3,3'-dimethyl-4,4'-diamino dibenzyl methane

Examples

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Embodiment 1

[0022] Add 200ml of water and 100ml (1.0mol) concentrated hydrochloric acid into a 500ml reactor equipped with heating, stirring, thermometer, and reflux condenser, control the reaction temperature at 20-30°C, and add 106g (1.0mol) o-toluidine dropwise under stirring , continue to stir for 20 minutes, add 0.6g 4,4'-dimethylaminopyridine (DMAP), maintain the temperature, slowly drop in 40g (0.5mol) 37% formaldehyde solution, react for 2 hours after dropping, slowly heat up to 80-90°C, react for 3 hours. Cool to 25°C, adjust pH to 7 with 25% NaOH solution, and white solid precipitates out. Filter, wash with water, dry, obtain 3,3'-dimethyl-4,4'-diaminodiphenylmethane crude product 113g, add 800ml ethanol, dimethylformamide mixed solution (according to ethanol: dimethylformamide =5:1 volume ratio preparation) for recrystallization to obtain 3,3'dimethyl-4,4'-diaminodiphenylmethane white crystals 87g, yield 77%, purity 99.3% (HPLC), melting point 158 -159°C

Embodiment 2

[0024] Add 200ml of water and 100ml (1.0mol) of concentrated hydrochloric acid into a 500ml reactor with heating, stirring, thermometer, and reflux condenser. The reaction temperature is controlled at 20-30°C, and 106g (1.0mol) of o-toluidine is added dropwise under stirring. , continue to stir for 20 minutes, add 0.8g 4,4'-dimethylaminopyridine (DMAP), maintain the temperature and add 15g (0.5mol) paraformaldehyde in batches, react for 2 hours, slowly heat up to 80-90°C, and react 3 hours. Cool to 20°C, adjust pH to 7 with 25% KOH solution, and white solid precipitates out. Filter, wash with water, dry, obtain 3,3'-dimethyl-4,4'-diaminodiphenylmethane crude product 115g, add 400ml ethanol, dimethylformamide mixed solution (according to ethanol: dimethylformamide =1:1 volume ratio preparation) to carry out recrystallization to obtain 3,3'-dimethyl-4,4'-diaminodiphenylmethane white crystal 91g, yield 80.5%, purity 99.2% (HPLC), melting point 158-159°C.

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Abstract

The present invention discloses a preparation method of 3,3-dimethyl-4,4-diaminodiphenyl methane. Said method includes the following steps: using o-toluidine as raw material, making it be reacted with hydrochloric acid to form salt, making it and condensation agent implement condensation reaction in the presence of catalyst, using alkaline solution to neutralize reaction product, and using mixed solution to make recrystallization so as to obtain the invented object product. Its purity can be up to above 99%, and its yield is 77-82%, and its melting point is 158-159 deg.C.

Description

technical field [0001] The invention relates to a preparation method of 3,3'-dimethyl-4,4'-diaminodiphenylmethane. Background technique [0002] 3,3'-Dimethyl-4,4'-diaminodiphenylmethane is an important chemical raw material, especially as a raw material for polyimide monomer or dipping paint. Its structural formula is: [0003] [0004] The method reported by Scanlan etc. is to react with o-toluidine, hydrochloric acid and formaldehyde solution. Under alkaline conditions, steam distills out the unreacted raw material o-toluidine, and the reactant obtained is through twice recrystallization to obtain 3,3 '-Dimethyl-4,4'-diaminodiphenylmethane, yield 63% (J.Am.Chem.Soc., 1935, May: 887-892). The method has high reaction temperature, many by-products, cumbersome post-treatment, low yield, multiple recrystallizations, high cost, and little prospect of industrialization. [0005] Barluenga et al. reported that o-toluidine reacted with paraformaldehyde in the presence of so...

Claims

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Application Information

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IPC IPC(8): C07C211/50C07C209/68
Inventor 何扣宝廖本仁蒋旭亮
Owner SHANGHAI CHEM REAGENT RES INST
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