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A method for continuous preparation of 3,3'-dichloro-4,4'-diaminodiphenylmethane

A technology of diaminodiphenyl and methane, which is applied in the field of continuous preparation 3, can solve the problems of continuous post-treatment process, unstable product quality, limited production capacity, etc. Easy to change color during storage and the effect of capacity expansion

Active Publication Date: 2022-03-04
JIANGSU RUIXIANG CHEM +1
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Problems solved by technology

[0003] In the prior art, US3297759A discloses a method for continuous preparation of 4,4'-diaminodiphenylmethane compounds. In the method, formaldehyde aqueous solution and aniline derivatives are mixed through a metering pump in a primary kettle, and the two Add hydrochloric acid to the first-stage kettle to mix, and finally enter the rearrangement kettle for rearrangement; in this process, o-chloroaniline and formaldehyde are fed into the first-stage kettle, which is easy to generate Schiff base impurities, and the product quality is low; hydrochloric acid, hydrochloric acid and formaldehyde The molar ratio is greater than 4:1, resulting in high hydrochloric acid unit consumption
[0004] US3478099A discloses a method for continuous preparation of 4,4'-diaminodiphenylmethane compounds. In this method, hydrochloric acid and aniline are mixed in a first-stage kettle to form a salt, and formaldehyde aqueous solution is added through a second-stage tubular reactor to mix. Finally, the crude product is obtained after rearrangement, neutralization, and water washing; this process uses a tubular reactor for condensation rearrangement, without stirring to promote mass transfer and heat transfer, which will easily lead to excessive local formaldehyde concentration and unstable product quality, and this method does not Mention post-processing serialization process
[0005] CN110818573A provides a preparation method of 3,3'-dichloro-4,4'-diaminodiphenylmethane, using the form of mixed acid composed of solid acid and liquid acid as catalyst and adopting azeotropic distillation to recycle the reaction liquid The liquid acid in the method makes full use of the respective advantages of solid acid and liquid acid, effectively reduces the consumption of liquid acid, reduces the corrosion loss of equipment, and improves the yield of MOCA; but this method still has a certain degree of operational complexity, limited capacity

Method used

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  • A method for continuous preparation of 3,3'-dichloro-4,4'-diaminodiphenylmethane

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Effect test

Embodiment 1

[0047] (1) Add 5110g of hydrochloric acid solution, 1276.3g of o-chloroaniline and 1500g of formaldehyde solution to the primary reaction kettle continuously and simultaneously, and carry out salt formation and condensation reaction at 50°C for 30min; wherein, the mass of hydrochloric acid in 5110g of hydrochloric acid solution The percentage concentration is 10%, containing 14mol of hydrochloric acid; the mass percent concentration of formaldehyde in 1500g formaldehyde aqueous solution is 10%, containing 5mol of formaldehyde; 1276.3g o-chloroaniline is analytically pure, and the purity is 99.9%; The ratio is 1.4:1:0.5;

[0048] (2) The reaction solution in the first-stage reaction kettle obtained after the condensation reaction of the step (1) is continuously overflowed into the first collection kettle, and rearranged to generate MOCA hydrochloride. After the material collection of the material tank is completed, the overflow of the first-level reactor is switched to the seco...

Embodiment 2

[0053] (1) Add 3163.3g of hydrochloric acid solution, 1276.3g of o-chloroaniline and 1500g of formaldehyde solution to the primary reaction kettle continuously and simultaneously, and carry out salt formation and condensation reaction at 40°C for 60 minutes; among them, the hydrochloric acid in the 3163.3g of hydrochloric acid solution The mass percent concentration of 15% of formaldehyde contains 13mol of hydrochloric acid; the mass percent concentration of formaldehyde in 1500g formaldehyde aqueous solution is 10%, containing 5mol of formaldehyde; 1276.3g of o-chloroaniline is analytically pure, and its purity is 99.9%; The molar ratio is 1.3:1:0.5;

[0054] (2) The reaction solution in the first-stage reaction kettle obtained after the condensation reaction of the step (1) is continuously overflowed into the first collection kettle, and rearranged to generate MOCA hydrochloride. After the material receiving tank is finished, the overflow of the first-stage reactor is switch...

Embodiment 3

[0059] (1) 2190g of hydrochloric acid solution, 1276.3g of o-chloroaniline and 1200g of formaldehyde aqueous solution were added dropwise to the primary reaction kettle simultaneously respectively, and salt formation and condensation reaction were carried out at 30°C for 90min; wherein, the mass of hydrochloric acid in 2190g of hydrochloric acid solution The percentage concentration is 20%, containing 12mol of hydrochloric acid; the mass percent concentration of formaldehyde in 1200g formaldehyde aqueous solution is 15%, containing 6mol of formaldehyde; 1276.3g o-chloroaniline is analytically pure, and the purity is 99.9%; The ratio is 1.2:1:0.6;

[0060] (2) The reaction solution in the first-stage reaction kettle obtained after the condensation reaction of the step (1) is continuously overflowed into the first collection kettle, and rearranged to generate MOCA hydrochloride. After the material receiving tank is finished, the overflow of the first-stage reactor is switched to...

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Abstract

The invention relates to a method for continuously preparing 3,3'-dichloro-4,4'-diaminodiphenylmethane. Hydrochloric acid solution, o-chloroaniline and formaldehyde aqueous solution are continuously and simultaneously added dropwise to a primary reactor Salt formation and condensation reaction are carried out in the medium; continuous rearrangement reaction and neutralization reaction are carried out by double-pot switching; continuous oil-water separation and continuous washing are carried out on the product; the purity and chromaticity stability of the obtained MOCA product are significantly improved; The present invention effectively solves the problems of MOCA and unreacted o-chloroaniline, which are ubiquitous in the prior art, are easy to change color after long-term heat storage, and the chromaticity of MOCA products is unstable and the production capacity is limited. Moreover, the synthesis process is automatically and continuously controlled, The overall production efficiency is significantly improved, and the acid consumption, alkali consumption and salty wastewater discharge are significantly reduced, the environmental protection effect is significantly enhanced, and the operation is simple, the economic cost is low, and the production capacity of a single production line is large, which is suitable for popularization and application.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a method for continuously preparing 3,3'-dichloro-4,4'-diaminodiphenylmethane. Background technique [0002] 3,3'-dichloro-4,4'-diaminodiphenylmethane is a commonly used aromatic diamine chain extender, commonly known as MOCA, which can be used as a crosslinking agent and curing agent for polyurethane and epoxy resins , can also be used as a vulcanizing agent for rubber, and can also be used to prepare some products with high electrical resistance. It is widely used in automobiles, machinery manufacturing, mining, sports facilities and other fields. DuPont of the United States took the lead in developing the synthesis process of MOCA. This process uses o-chloroaniline, formaldehyde and hydrochloric acid as raw materials. First, o-chloroaniline and hydrochloric acid are reacted to form o-chloroaniline hydrochloride, and then condensed with formaldehyde to form MOCA hydrochl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C211/52C07C209/00C07C209/54
CPCC07C209/00C07C209/54C07C209/60C07C249/02C07C211/52C07C211/53C07C251/04
Inventor 王怡明丁克鸿徐林刘相李张巍伟卞辰超赵慧
Owner JIANGSU RUIXIANG CHEM
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