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Process for preparing 4,4'-diaminodiphenylmethane through condensation of acidic ionic liquid catalytic aniline and formaldehyde

A technology of diaminodiphenylmethane and acidic ionic liquid, which is applied in the field of green chemistry, can solve the problems of difficult reuse of catalysts, high corrosion of liquid strong acids, and large waste water discharge, so as to achieve good industrial application prospects and overcome the post-treatment process cumbersome, low vapor pressure effect

Active Publication Date: 2014-12-17
HEBEI UNIV OF TECH
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  • Abstract
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  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide an acidic ionic liquid for the existing 4,4'-MDA synthesis technology, which has the problems of high corrosiveness of liquid strong acid, difficult separation of products, difficulty in reusing catalysts, and large amount of waste water discharge. Catalyzed Condensation of Aniline and Formaldehyde to Prepare 4,4'-MDA

Method used

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  • Process for preparing 4,4'-diaminodiphenylmethane through condensation of acidic ionic liquid catalytic aniline and formaldehyde
  • Process for preparing 4,4'-diaminodiphenylmethane through condensation of acidic ionic liquid catalytic aniline and formaldehyde
  • Process for preparing 4,4'-diaminodiphenylmethane through condensation of acidic ionic liquid catalytic aniline and formaldehyde

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Embodiment 1

[0039] In the three-necked flask, add 3.418g [HSO 3 -bmim]C 6 h 6 SO 3 Ionic liquid and 15.331g aniline (0.165mol), magnetically stirred, and 2.634g formaldehyde aqueous solution (mass fraction: 37%, formaldehyde 0.032mol) was added dropwise at 50℃. Reaction 8h. After the reaction was finished, it was cooled to room temperature, and a sample was analyzed by liquid chromatography. The conversion rate of aniline was 33.3%, and the yield and selectivity of 4,4'-MDA were 63.8% and 75.5% (4,4'-MDA's Yield is based on formaldehyde, selectivity is based on aniline).

[0040] After the reaction, water was added to the reaction solution for extraction, and the aqueous layer and the organic layer were separated. The aqueous layer was rotatably evaporated, and the ionic liquid was recovered and reused.

[0041] Examples 2-44 were carried out according to the operation steps of Example 1, and the reaction conditions and results are shown in the summary table.

[0042]

[0043] ...

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Abstract

The invention provides a process for preparing 4,4'-diaminodiphenylmethane (4,4-MDA) through condensation of acidic ionic liquid catalytic aniline and formaldehyde. The process includes the first step of adding aniline and acidic ionic liquid into a reactor provided with a backflow condensing device, dropwise adding a formalin solution into the reactor at 30-60 DEG C, stirring the mixture for 5-45 minutes, and then raising the temperature to 60-120 DEG C to react for 2-10 hours, wherein the raw material molar ratio is that aniline: formaldehyde=2-10: 1, and the catalyst mass ratio is that the acidic ionic liquid: the formaldehyde=0.5-10: 1, the second step of using water to extract reaction liquid, obtaining a water layer and an organic layer through separation, carrying out spin-steaming on the water layer, and recycling the ionic liquid for repeat use. The process is mild in reaction condition, high in catalyst activity and good in selectivity, and the prepared 4,4'-diaminodiphenylmethane can be repeatedly used.

Description

technical field [0001] The invention relates to the technical field of green chemistry, in particular to a process for preparing 4,4'-diaminodiphenylmethane by using an acidic ionic liquid to catalyze the condensation of aniline and formaldehyde. Background technique [0002] 4,4'-Diaminodiphenylmethane (4,4'-MDA) is an important raw material for the synthesis of polyurethane MDI. In addition, as an important chemical, it is also widely used in many fields, such as being used as a tough curing agent for epoxy resin, as a chain extender, and as a preparation of polyesterimide (PEI) and polyimide Imine (PI) insulating varnish, bima resin and other insulating materials can also be used to synthesize dyes such as basic bright yellow O, basic violet 5BN and triarylmethane. It is precisely because 4,4'-MDA has such important and wide applications that its synthesis method has attracted people's attention and has been one of the research hotspots at home and abroad. [0003] At p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C211/50
Inventor 赵新强田金萍安华良王延吉
Owner HEBEI UNIV OF TECH
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