阅读说明：本技术 一种利用微通道反应器连续化制备3，3’-二氯-4，4’-二氨基二苯基甲烷的方法 (Method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using microchannel reactor ) 是由 王怡明 丁克鸿 徐林 刘相李 张巍伟 卞辰超 赵慧 于 2020-06-11 设计创作，主要内容包括：本发明涉及一种利用微通道反应器连续化制备3,3’-二氯-4,4’-二氨基二苯基甲烷的方法,将盐酸溶液和邻氯苯胺分别同时泵入微通道成盐模块中进行成盐反应,所得邻氯苯胺盐酸盐溶液送入微通道缩合重排模块与甲醛溶液进行缩合和重排反应；所得缩合重排反应液送入微通道中和模块与碱液进行中和反应；对产物进行连续化油水分离,分离所得油层进入微通道水洗模块进行水洗后再进行油水分离；所得MOCA产品纯度达到95％以上,且色度稳定。本发明通过利用微通道反应器,在不同的微通道反应器模块上依次连续进行均相进料,实现连续化生产MOCA,大幅提高生产效率,显著提升产品均一性和稳定性,全流程自动化操作,适于工业化推广应用。(The invention relates to a method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor, which comprises the steps of respectively pumping a hydrochloric acid solution and o-chloroaniline into a microchannel salifying module at the same time for salifying reaction, and feeding the obtained o-chloroaniline hydrochloride solution into a microchannel condensation rearrangement module for condensation and rearrangement reaction with a formaldehyde solution; feeding the obtained condensation rearrangement reaction liquid into a micro-channel neutralization module to perform neutralization reaction with alkali liquor; performing continuous oil-water separation on the product, and enabling the separated oil layer to enter a micro-channel water washing module for water washing and then performing oil-water separation; the purity of the obtained MOCA product reaches more than 95 percent, and the chroma is stable. According to the invention, the microchannel reactor is utilized to sequentially and continuously perform homogeneous phase feeding on different microchannel reactor modules, so that continuous MOCA production is realized, the production efficiency is greatly improved, the product uniformity and stability are obviously improved, the full-process automatic operation is realized, and the method is suitable for industrial popularization and application.)

1. A method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor is characterized by comprising the following steps:

(1) respectively and simultaneously pumping the hydrochloric acid solution and o-chloroaniline into a micro-channel salifying module to carry out salifying reaction to obtain an o-chloroaniline hydrochloride solution;

(2) sending the o-chloroaniline hydrochloride solution obtained in the step (1) into a microchannel condensation rearrangement module, simultaneously pumping formaldehyde solution into the microchannel condensation rearrangement module, and carrying out condensation and rearrangement reaction in the microchannel condensation rearrangement module;

(3) feeding the condensation rearrangement reaction liquid obtained in the step (2) into a micro-channel neutralization module, and simultaneously pumping alkali liquor into the micro-channel neutralization module to perform neutralization reaction in the micro-channel neutralization module;

(4) feeding the neutralization reaction liquid obtained in the step (3) into a first delayer, carrying out oil-water separation, feeding an oil layer obtained by separation into a micro-channel washing module for washing, and carrying out steam stripping on a water layer obtained by separation to recover o-chloroaniline;

(5) and (3) feeding the product obtained after the micro-channel washing module in the step (4) is washed by water into a second layer separator, carrying out oil-water separation, feeding the upper water layer obtained by separation into a distillation reactor for steam stripping to recover water, and feeding the lower oil layer obtained by separation into a product collecting tank for collection and drying to obtain the MOCA product.

2. The continuous production method of 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor as claimed in claim 1, wherein in step (1), the hydrochloric acid solution has a concentration of 10% to 25% by mass of hydrochloric acid.

3. The method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor according to claim 1, wherein in the step (1) and the step (2), the molar ratio of the hydrochloric acid to the o-chloroaniline to the formaldehyde is (1.5 to 1.1): 1: (0.4-0.7).

4. The continuous production method of 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor as claimed in claim 1, wherein in the step (2), the concentration of formaldehyde in the aqueous formaldehyde solution is 10% to 37% by mass.

5. The continuous production method of 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor as claimed in claim 1, wherein in step (2), the feeding manner of the formaldehyde solution is one feed or a plurality of feeds.

6. The continuous process for preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using microchannel reactor as claimed in claim 1, wherein in step (2), there are n sets of said microchannel condensation rearrangement modules, and said n sets of said microchannel condensation rearrangement modules are connected in series in turn, and each set of said microchannel condensation rearrangement modules individually corresponds to one feed of said formaldehyde solution.

7. The continuous preparation method of 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using microchannel reactor as claimed in claim 1, wherein in the step (1), the step (2) and the step (3), the temperature in the microchannel salt-forming module, the microchannel condensation rearrangement module and the microchannel neutralization module is 80 ℃ to 120 ℃.

8. The continuous process for preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using microchannel reactor as claimed in claim 1, characterized in that in step (3), the lye is sodium hydroxide solution.

9. The continuous preparation method of 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane with microchannel reactor as claimed in claim 8, characterized in that in step (3), the molar ratio of sodium hydroxide to hydrochloric acid is (1.0-1.3): 1.

10. The continuous production method of 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor as claimed in any one of claims 1 to 9, characterized in that the total reaction time of step (1), step (2) and step (3) is 30s to 300 s.

Technical Field

The invention relates to the technical field of fine chemical engineering, in particular to a method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor.

Background

3, 3 '-dichloro-4, 4' -diaminodiphenylmethane is a commonly used aromatic diamine chain extender, commonly called MOCA, can be used as a cross-linking agent, a curing agent and a vulcanizing agent, can also be used for preparing products with higher electric resistance, and is widely applied in a plurality of industrial fields of airplanes, automobiles, mining and the like.

In 1953, DuPont, USA, who developed MOCA synthesis technology, first reacted o-chloroaniline with hydrochloric acid to generate o-chloroaniline hydrochloride, then condensed the salt solution with formaldehyde to generate MOCA hydrochloride, then neutralized the hydrochloric acid with NaOH, and finally obtained MOCA product through water washing, steam distillation and other steps. The production process mostly adopts a kettle type batch reactor, has long reaction time, complicated operation, difficult realization of continuous production, long treatment process after reaction, complicated steps, high energy consumption and easy reduction of MOCA product quality.

CN105294448B discloses a method for continuously preparing 4, 4-diaminodiphenylmethane derivatives by solid acid catalysis, which comprises the steps of taking aniline derivatives and formaldehyde as raw materials, and carrying out condensation reaction by solid acid catalysis in a first-stage or second-stage fixed bed reactor to obtain the 4, 4-diaminodiphenylmethane derivatives (MDA, MDT and MOCA). The method uses solid acid H beta, HY and HZSM-5 molecular sieves to replace traditional inorganic acid catalysts such as hydrochloric acid and sulfuric acid, and the process is simpler; however, the MOCA synthesized by the process has low yield, high unit consumption of o-chloroaniline, easy inactivation of the solid acid catalyst and difficult regeneration, and research stays in a laboratory pilot plant stage, so that industrialization is not realized.

CN205933698U discloses a 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane continuous condensation device, which comprises a micro-reactor, a tubular reactor and a neutralization kettle which are sequentially communicated, wherein a material inlet of the micro-reactor is respectively communicated with a raw material metering tank and the micro-reactor through a metering pump, the temperature of the micro-reactor is controlled after the material enters the micro-reactor, the material enters the neutralization kettle through the tubular reactor for neutralization, and a product MOCA is obtained after the neutralization; the method has the advantages of low energy consumption and realization of continuous production in partial steps, but the tubular reactor adopts gravity to push materials to flow, so that the mixing effect is poorer than that of the traditional kettle type reactor, and the mass and heat transfer efficiency is low.

CN106986777B discloses a method for preparing 4, 4-diaminodiphenylmethane derivatives by using a microreactor, which comprises the steps of conveying aniline derivative hydrochloride and formaldehyde solution into the microreactor through a advection pump respectively for contact, mixing and reaction, then cooling, dropwise adding sodium hydroxide aqueous solution, separating out white precipitate, filtering and drying to obtain crude 4, 4-diaminodiphenylmethane derivatives (MDA, MDT or MOCA), recrystallizing with ethanol, filtering, and drying to obtain pure products. The method needs to be provided with a separate salifying kettle, the salifying liquid is a solid-liquid two-phase mixture, and the liquid-solid two-phase mixture is fed, so that the system can not continuously run due to the blockage of a micro-channel.

Therefore, improvement of the MOCA synthesis process, product quality enhancement, production efficiency improvement, raw material loss reduction and wastewater discharge reduction, and industrial large-scale production are urgently needed.

Disclosure of Invention

The invention aims to provide a method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor, which aims to solve the problems in the prior art, reduce side reactions, enhance the product quality, improve the production efficiency, reduce the raw material loss and the wastewater discharge so as to realize green and environment-friendly industrial scale-up production.

The technical scheme for solving the problems is as follows: a method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor comprises the following steps:

(1) respectively and simultaneously pumping the hydrochloric acid solution and o-chloroaniline into a micro-channel salifying module to carry out salifying reaction to obtain an o-chloroaniline hydrochloride solution;

(2) sending the o-chloroaniline hydrochloride solution obtained in the step (1) into a microchannel condensation rearrangement module, simultaneously pumping formaldehyde solution into the microchannel condensation rearrangement module, and carrying out condensation and rearrangement reaction in the microchannel condensation rearrangement module;

(3) feeding the condensation rearrangement reaction liquid obtained in the step (2) into a micro-channel neutralization module, and simultaneously pumping alkali liquor into the micro-channel neutralization module to perform neutralization reaction in the micro-channel neutralization module;

(4) feeding the neutralization reaction liquid obtained in the step (3) into a first delayer, carrying out oil-water separation, feeding an oil layer obtained by separation into a micro-channel washing module for washing, and carrying out steam stripping on a water layer obtained by separation to recover o-chloroaniline;

(5) and (3) feeding the product obtained after the micro-channel washing module in the step (4) is washed by water into a second layer separator, carrying out oil-water separation, feeding the upper water layer obtained by separation into a distillation reactor for steam stripping to recover water, and feeding the lower oil layer obtained by separation into a product collecting tank for collection and drying to obtain the MOCA product.

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor, in the step (1), the mass percentage concentration of hydrochloric acid in the hydrochloric acid solution is 10% to 25%.

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using the microchannel reactor, in the step (1) and the step (2), the molar ratio of the hydrochloric acid to the o-chloroaniline to the formaldehyde is (1.5-1.1): 1: (0.4-0.7).

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor, in the step (2), the mass percentage concentration of formaldehyde in the formaldehyde aqueous solution is 10% to 37%.

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor according to the present invention, in the step (2), the feeding manner of the formaldehyde solution is one feed or a plurality of feeds.

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor according to the present invention, in the step (2), there are n sets of the microchannel condensation rearrangement modules, the n sets of the microchannel condensation rearrangement modules are sequentially connected in series, and each set of the microchannel condensation rearrangement modules individually corresponds to one feed of the formaldehyde solution.

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor, in the step (1), the step (2) and the step (3), the temperature in the microchannel salt-forming module, the microchannel condensation rearrangement module and the microchannel neutralization module is 80 to 120 ℃.

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using the microchannel reactor, in the step (3), the alkali liquor is sodium hydroxide solution.

Further, in the method for continuously preparing the 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using the microchannel reactor, in the step (3), the molar ratio of the sodium hydroxide to the hydrochloric acid is (1.0-1.3): 1.

Further, in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using the microchannel reactor, the total reaction time of the step (1), the step (2) and the step (3) is 30-300 s.

Compared with the prior art, the invention has the beneficial effects that: the MOCA is creatively prepared by using the microchannel reactor, and the process design is optimized, so that the problems of poor heat transfer effect, poor material mixing effect, heterogeneous feeding, incapability of continuous production and the like in the prior art are effectively solved; the method has the advantages that materials are sequentially and continuously conveyed on different microchannel reactor modules by utilizing the microchannel reactor, so that continuous production of MOCA is realized, meanwhile, the raw materials are fully contacted through homogeneous feeding of reaction raw materials, the specific surface area is large, the heat and mass transfer efficiency is fully improved, so that the raw material mixing and contacting time is short, the reaction is fast and uniform, byproducts are few, the product quality uniformity and stability are remarkably improved, the purity of the obtained MOCA product can reach more than 95%, the chromaticity is stable, and the economic benefit is remarkably enhanced; in addition, because the mass transfer and the reaction process are completed in the micro-reaction channel, a conventional stirring device is not needed, the operation complexity is reduced, and meanwhile, the energy consumption such as acid consumption, alkali consumption and the like is greatly reduced; by using the microchannel reactor, the raw materials are fully and uniformly contacted, no local aggregation exists, the reaction safety is high, the full process is automatically operated, no amplification effect exists in the industrial process, and the method is suitable for large-scale popularization and application.

Drawings

FIG. 1 is a schematic partial flow diagram of a process for the continuous preparation of 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor according to the present invention;

FIG. 2 is a schematic diagram of the distribution process of the microchannel condensation rearrangement module in the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using the microchannel reactor.

Detailed Description

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, the raw materials and reagents in the examples of the present invention were all purchased from commercial sources.

As shown in figure 1, the method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using the microchannel reactor comprises the following steps:

(1) respectively and simultaneously pumping the hydrochloric acid solution and o-chloroaniline into a micro-channel salifying module to carry out salifying reaction to obtain an o-chloroaniline hydrochloride solution;

(2) sending the o-chloroaniline hydrochloride solution obtained in the step (1) into a microchannel condensation rearrangement module, simultaneously pumping formaldehyde solution into the microchannel condensation rearrangement module, and carrying out condensation and rearrangement reaction in the microchannel condensation rearrangement module;

(3) feeding the condensation rearrangement reaction liquid obtained in the step (2) into a micro-channel neutralization module, and simultaneously pumping alkali liquor into the micro-channel neutralization module to perform neutralization reaction in the micro-channel neutralization module;

(4) feeding the neutralization reaction liquid obtained in the step (3) into a first delayer, carrying out oil-water separation, feeding an oil layer obtained by separation into a micro-channel washing module for washing, and carrying out steam stripping on a water layer obtained by separation to recover o-chloroaniline;

(5) and (3) feeding the product obtained after the micro-channel washing module in the step (4) is washed by water into a second layer separator, carrying out oil-water separation, feeding the upper water layer obtained by separation into a distillation reactor for steam stripping to recover water, and feeding the lower oil layer obtained by separation into a product collecting tank for collection and drying to obtain the MOCA product.

In the method for continuously preparing the 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using the microchannel reactor, the MOCA preparation production thinking of the traditional batch process and other continuous processes is broken through, the microchannel reactor is innovatively adopted for continuously preparing the MOCA, and the overall process is optimally designed based on the combination of the characteristics of the microchannel reactor and the reaction process of the MOCA preparation, so that a plurality of microchannel reactor modules are combined into a system for continuously preparing the MOCA; in the microchannel salifying module, the microchannel condensation rearrangement module, the microchannel neutralization module and the microchannel water washing module, feeding materials such as hydrochloric acid solution, o-chloroaniline, formaldehyde solution, alkali liquor, water washing water and the like in a continuous flow mode through a micro pipeline of each microchannel reactor module respectively, and enabling the materials to enter reaction materials in each microchannel reactor module for rapid mixing; in the process, each material fluid is fully contacted with the wall of the corresponding microchannel reactor module, and the in-situ efficient heat exchange in the reaction process is realized based on the extremely large specific surface area of the microchannel reactor; the materials fed by the micro-pipeline continuous flow are uniformly distributed in a flow field in a laminar flow state, the contacted materials are uniformly and quickly mixed, and the reaction liquid is homogeneous at each reaction stage of MOCA, so that the retention time and the reaction temperature of the materials under the reaction condition can be accurately controlled, the initiation or termination of the reaction is facilitated, and the reaction safety is effectively controlled; therefore, MOCA is prepared by the process method designed by the invention, the uniformity of the obtained product is improved, the generated byproducts are reduced, the MOCA is green and safe, the side reactions are few, the mass production can be realized by adding a micro-reaction unit, the amplification effect is basically avoided, the full process is automatically operated, and the MOCA is suitable for large-scale industrial popularization and application.

In the above method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor, each material is fed homogeneously in a continuous flow manner through the microchannel of each microchannel reactor module, and after the reaction, the material is continuously fed into the next step stage as homogeneous output, specifically, in step (1), the following salt-forming reaction occurs:

in step (2), the following condensation and rearrangement reactions occur:

in step (3), the following neutralization reaction occurs:

in order to ensure the quality of MACA products such as purity, chromaticity and the like, preferably, in the step (1), the mass percentage concentration of hydrochloric acid in the hydrochloric acid solution is 10-25%; in the step (2), the mass percentage concentration of formaldehyde in the formaldehyde aqueous solution is 10-37%; in the step (1) and the step (2), the molar ratio of the hydrochloric acid to the o-chloroaniline to the formaldehyde is (1.5-1.1): 1: (0.4 to 0.7); in the step (3), in order to guarantee the neutralization effect, the alkali liquor is preferably a sodium hydroxide solution, and the molar ratio of sodium hydroxide to hydrochloric acid is (1.0-1.3): 1, so as to guarantee the neutralization efficiency; more preferably, in the step (1), the step (2) and the step (3), the temperature of the microchannel salifying module, the microchannel condensation rearrangement module and the microchannel neutralization module is controlled to be 80-120 ℃, so as to be beneficial to realizing homogeneous feeding, and particularly, the o-chloroaniline hydrochloride is dissolved in hydrochloric acid to provide guarantee for homogeneous continuous reaction; and (3) controlling the total reaction time of the step (1), the step (2) and the step (3) to be 30-300 s, and avoiding the problems of unstable chromaticity and the like caused by overlong reaction time.

In the above-mentioned method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane using a microchannel reactor, in the step (2), the feeding manner of the formaldehyde solution can be one-strand feeding or multi-strand feeding, and preferably, the feeding manner of the formaldehyde solution is multi-strand feeding; the number of the microchannel condensation rearrangement modules is n (n is more than or equal to 1), preferably, more than two groups of the microchannel condensation rearrangement modules are provided, and preferably, 3-5 groups of the microchannel condensation rearrangement modules are provided; when the microchannel condensation rearrangement module has more than two groups, preferably, the n groups of microchannel condensation rearrangement modules are sequentially connected in series, each group of microchannel condensation rearrangement modules respectively and independently corresponds to one feed of the formaldehyde solution, as shown in fig. 2, by taking 5 groups of microchannel condensation rearrangement modules as an example, namely, a first microchannel condensation rearrangement module, a second microchannel condensation rearrangement module, a third microchannel condensation rearrangement module, a fourth microchannel condensation rearrangement module and a fifth microchannel condensation rearrangement module are sequentially connected in series, when the device is specifically operated, the adjacent chloroaniline hydrochloride solution obtained in step (1) sequentially enters the first microchannel condensation rearrangement module, the second microchannel condensation rearrangement module, the third microchannel condensation rearrangement module, the fourth microchannel rearrangement module and the fifth microchannel condensation rearrangement module, and simultaneously, the formaldehyde solution is equally divided into five feeds, pumping formaldehyde solution into each microchannel condensation rearrangement module respectively by each feed, carrying out condensation and rearrangement reaction in each microchannel condensation rearrangement module, and finally conveying reaction liquid to the microchannel neutralization module through the fifth microchannel condensation rearrangement module; therefore, through the arrangement of the plurality of groups of microchannel condensation rearrangement modules, formaldehyde is fed in a plurality of strands in a segmented manner, the reaction is guaranteed, the concentration of formaldehyde in a single microchannel condensation rearrangement module is reduced, the self-polymerization of formaldehyde and the side reaction of impurities such as tripolymer and tetramer generated by the reaction of the formaldehyde and o-chloroaniline hydrochloride are reduced, and the purity and the yield of MOCA products are improved.

In the above-mentioned method for continuously preparing 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane by using a microchannel reactor, the MOCA product obtained in step (5), i.e. 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane, is subjected to a colorimetric test, preferably, the MOCA colorimetric measurement method specified in the trade mark HG/T2711-2012 is adopted, namely: preparing potassium chloroplatinate-hydrochloric acid colorimetric solutions with different contents to obtain colorimetric solutions with 1-8 # chroma, transferring the molten MOCA product into a nano colorimetric tube, and performing visual comparison on the molten MOCA product and the colorimetric solution with the potassium chloroplatinate-hydrochloric acid colorimetric solutions to obtain the chroma of the product; test analysis shows that the color intensity of the MOCA product prepared by the invention meets the standard, is stable and is obviously superior to that of products obtained by the traditional intermittent and other continuous processes.

The present invention will be further described in more detail with reference to more specific application examples, but the present invention is not limited to any examples.