CN101143828A - Continuous reaction technique for producing crude MDA - Google Patents
Continuous reaction technique for producing crude MDA Download PDFInfo
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- CN101143828A CN101143828A CNA2007100654227A CN200710065422A CN101143828A CN 101143828 A CN101143828 A CN 101143828A CN A2007100654227 A CNA2007100654227 A CN A2007100654227A CN 200710065422 A CN200710065422 A CN 200710065422A CN 101143828 A CN101143828 A CN 101143828A
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Abstract
The invention discloses a continuous reaction technique which utilizes the condensation reaction between aniline and formaldehyde under the existance of hydrochloric acid catalyst to prepare crude MDA. According to a certain proportion, aniline hydrochloride solution and the formaldehyde enter into an injection mixer for rapid and sufficient mixing and then enter into a segmented pre-condensation reactor for stepwise pre-condensation reaction, after being heated, a pre-condensed product enters into a tubular first transposition device, and after being further heated, enters into a horizontal second transposition device, so that the crude MDA is generated by transposition. After the condensed solution undergoes the refining of neutralization, water washing, aniline removal and dehydration, the crude MDA is produced. The crude MDA produces MDI though the phosgenation reaction.
Description
Technical field
The invention belongs to the continuous reaction process that a kind of polyphenyl polymethylene polyamines (thick MDA) is produced.
Background technology
Ditan-4,4 '-vulcabond (MDI) is made by phosgenation reaction by polyphenyl polymethylene polyamines (being called for short polyamines, thick MDA, thick DAM).Aniline and formaldehyde make thick MDA through condensation reaction, and reaction mainly is made up of two steps, and the first step aniline and formaldehyde carry out the precondensation reaction and generates the secondary amine mixture in the presence of an acidic catalyst (generally selecting hydrochloric acid):
Second goes on foot secondary amine class material transposition at high temperature generates primary amine class material (being polyamines):
Condensated liquid with in the NaOH solution and after, the organic phase of telling through washing, take off the aniline dehydration and obtain thick MDA after refining, thick MDA generates MDI through phosgenation reaction.
Thick MDA is grouped into by multiple one-tenth such as diamines, triamine, tetramine, five amine, and every kind of amine has multiple isomer again.Wherein the main component of diamines is 4,4 ' isomer, and other has 2,2 ' isomer of a spot of 2,4 ' isomer and trace.Also have multiple side reaction during the aniline formaldehyde condensation, main by product is the N-methyl compound, and the N-methyl compound of two phenyl ring is called for short MMM, and molecular formula is:
Stay in the MDI product through these impurity of phosgenation reaction, have a strong impact on the quality of MDI product.
Different thick MDA production according to manufacturing process is divided into interrupter method, semi-continuous process and continuous processing.Interrupter method is owing to exist reinforced, discharging and unproductive time such as cleaning, and the production cycle is long, plant factor is not high, and industrial scale is less.The reaction conditions of each batch can not be in full accord in the batch production, unstable product quality.
The successive reaction fado adopts multistage caldron process, as: the disclosed technology of US5053539.There is back-mixing in material, causes diamine contents to reduce.Patent DD300166 has adopted the pipe type continuously technology, and its formaldehyde adds employing static mixing method, and mixed temperature is 70～80 ℃.Temperature is higher after the mixing of materials, and is unfavorable to diamine contents, and side reaction product N-methyl compound amount increases, and influences quality product.Patent CN1151119 discloses a half-continuous process, reduces the N-methyl compound content among the MDA, be suitable for the manufacturing of many phenyl ring amine of high level, but quality product is still not satisfactory.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of continuous condensating technology, improves diamine contents among the thick MDA, reduces side reaction product N-methyl compound amount, improves the quality of products, and avoids precipitation to cause line clogging.The thick MDA general requirement diamine contents wherein height of will trying one's best in continuous processing, for reaching this purpose, must be avoided the back-mixing of material, and tubular reactor is optimal selection.But tubular reactor brings the other problem again.
Precondensation reaction is faster reaction, must make the material short mix even, enters the tubular reactor reaction then, otherwise side reaction increases, and influences quality product.In tubular reactor, reaction easily produces precipitation, even causes line clogging, and in concentration of formaldehyde height, this situation of easier appearance when temperature of reaction is low, promptly the entrance at tubular reactor takes place easily.In process of the test, we observe in the reactor inlet section, of short duration material occurs by the muddy phenomenon of bleach again of transparent change.This is big with herein response intensity, temperature is low relevant.Temperature is low favourable to the precondensation reaction, and the mass-and heat-transfer of strengthening the initial section reaction so becomes optimal selection.Translocation reaction is relatively slow, finishes the reaction needed long period, but most of reaction can finish within a short period of time, and translocation reaction is carried out reducing equipment does not stage by stage influence diamine contents again.
Technology of the present invention is: aniline, hydrochloric acid, water are mixed by a certain percentage, generate anilinechloride solution under the temperature control condition; Anilinechloride solution is as main flow, and formaldehyde enters jet mixer by a certain percentage as time stream and carries out short mix; Mixed solution enters sectional precondensation reactor, the reaction of proceed step by step precondensation; Enter tubular type first inversion device after the heating of precondensation liquid and carry out translocation reaction, generate polyamines, enter second changer behind the reheat, make transposition complete; Condensated liquid obtains thick MDA through the neutralization washing after making with extra care.Molar ratio of material of the present invention is: aniline/hydrochloric acid/formaldehyde/water=1/0.3～1.0/0.2～0.49/4.5～6.0.
Optimal way of the present invention: 20～40 ℃ of anilinechloride solution are as main flow; formaldehyde mixes in jet mixer as time stream; venturi-type eductors or other can guarantee the uniform injector of material short mix all can, pressure reduction 0.3～0.6MPa guarantees to mix before and after the mixing tank.Volume ratio 6～the 10:1 of anilinechloride and formaldehyde solution, for reaching this ratio, formaldehyde can adopt multi-stage jet to mix.Mixed material enters first section tubular reactor, material flow 5～10m/s, 0.5～2 second residence time, material directly enters second section tubular reactor then, material flow is 0.5m/s～1.5m/s in the pipe, 30～60 seconds residence time, 30～60 ℃ of temperature of reaction, logical water coolant cools off in the chuck.A focus can occur in second section tubular reactor, for the temperature of controlling this some place is not higher than 60 ℃, formaldehyde divides multi-stage jet to add in case of necessity.Most of formaldehyde reacts in second section tubular reactor, and material enters the 3rd section precondensation reactor, and the preferential shell and tube heat exchanger that adopts of this section also can adopt the reactor of being with heat exchange, and 1～10 minute residence time, temperature out is controlled at below 60 ℃.The precondensation liquid that the precondensation reactor comes out is heated to the first inversion device that enters tubular type after 90～100 ℃, and changer is vertical, and precondensation liquid enters from the upper end, and the residence time of material is 3～10 minutes, about flow velocity 1～5cm/s.To become primary amine be MDA in most of secondary amine transposition in the tubular type changer.After condensated liquid comes out to be heated to 100～140 ℃ from tubular type changer bottom, enter the residence time and be 30～120 minutes horizontal second changer, make transposition complete.In condensated liquid, add NaOH solution, neutralization HCl wherein, the material phase-splitting, organic phase through wash, dewater, take off aniline refining after, must thick MDA.
Most preferably mode of the present invention: the pressure reduction of jet mixer is 0.4MPa, the volume ratio 8～10: 1 of anilinechloride and formaldehyde solution; First section tubular type precondensation reactor, material flow be greater than 8m/s, about 1 second residence time, and 50 ℃ of the temperature vertexs in second section tubular type precondensation reactor; The temperature of first inversion device is 98 ℃, 5 minutes residence time; The temperature of second changer is 110 ℃, 90 minutes residence time.
The precondensation reactor of technology of the present invention is divided into three sections, by first section mass transfer, the heat transfer that increased flow velocity reinforced, avoid sedimentary generation, material can make under the situation of most of formaldehyde at no back-mixing in the residence time of second section tubular reactor and react, and the 3rd section reactor takes out reaction heat and residual formaldehyde is reacted completely.Be design and the layout that makes things convenient for equipment, translocation reaction divides two sections to carry out, and the first inversion device adopts tubular reactor, helps the raising of diamine contents, and second changer adopts long horizontal reactor of the residence time, guarantees that transposition is complete.Adopt jet mixer, formaldehyde and aniline are mixed in the short period of time at the utmost point, avoid the local excessive side reaction that causes of formaldehyde.The control of precondensation temperature of reaction helps improving diamine contents at a lower temperature, reduces side reaction product N-methyl compound.Formaldehyde adds and can once add, also can repeatedly add, by the flow of material proportion, injector primary-to-secondary flow when the hot(test)-spot temperature of second section precondensation reactor determine jointly.Present method has effectively improved quality product, and makes constant product quality.
Using distinct device application present method to produce thick MDA all drops within protection scope of the present invention.
Embodiment
Embodiment 1
Material proportion is an aniline: hydrochloric acid: formaldehyde: water (mol ratio)=1: 0.6: 0.3: 4.8, and the inlet amount of anilinechloride is 690kg/h, 31.4 ℃ of temperature, the inlet amount of formaldehyde are 92kg/h.The pressure reduction of jet mixer is 0.32MPa, and the vertex of tubular type precondensation temperature is 42 ℃, and the temperature of first inversion device is 98 ℃, and 5 minutes residence time, the second changer temperature is 110 ℃, 60 minutes residence time.Thick MDA forms with the gas chromatograph analysis, and getting diamine contents is 82.9%, and wherein 2,4 ' body accounts for 9.28%, and transposition secondary amine is not that 0.21%, two phenyl ring N-methyl compound is 0.12%.
Embodiment 2
Material proportion is identical with embodiment 1 with flow, 23 ℃ of aniline salt acid solution temperature, and the pressure reduction of jet mixer is 0.33MPa, tubular type precondensation temperature is 36 ℃, and the temperature of first inversion device is 94 ℃, 8 minutes residence time, the second changer temperature is 120 ℃, 90 minutes residence time.Thick MDA forms: diamine contents is 83.2%, and wherein 2,4 ' body accounts for 8.96%, and transposition secondary amine is not that 0.13%, two phenyl ring N-methyl compound is below 0.1%.
Embodiment 3
Material proportion is identical with embodiment 1 with flow, 40 ℃ of aniline salt acid solution temperature, and the pressure reduction of jet mixer is 0.3MPa, tubular type precondensation temperature is 53 ℃, and the temperature of first inversion device is 100 ℃, 3 minutes residence time, the second changer temperature is 125 ℃, 40 minutes residence time.Thick MDA forms: diamine contents is 81.8%, and wherein 2,4 ' body accounts for 9.41%, and transposition secondary amine is not that 0.19%, two phenyl ring N-methyl compound is 0.15%.
Embodiment 4
Material proportion is an aniline: hydrochloric acid: formaldehyde: water (mol ratio)=1: 0.8: 0.4: 5, and the inlet amount of aniline hydrochloric acid is 710kg/h, 35 ℃ of temperature, the inlet amount of formaldehyde are 122kg/h.The pressure reduction of jet mixer is 0.4MPa, and the vertex of tubular type precondensation temperature is 63 ℃, and the temperature of first inversion device is 95 ℃, and 5 minutes residence time, the second translocation reaction actuator temperature is 110 ℃, 60 minutes residence time.Diamine contents is 74.2% among the thick MDA, and wherein 2,4 ' body accounts for 4.7%, and transposition secondary amine is not 0.26%, two phenyl ring N-methyl compound 0.42%.The formaldehyde amount of this example is big, precondensation temperature height, and reaction is violent, causes two phenyl ring N-methyl compound content height.
Example 5
Material proportion, flow are identical with example 4, and formaldehyde changes two-stage into and sprays and add, and the principal goods material is cooled to 30 ℃ before the charging of the second stage, and the vertex of first step tubular type precondensation temperature is 51 ℃, and the vertex of first step tubular type precondensation temperature is 47 ℃.Diamine contents is 75.4% among the thick MDA, and wherein 2,4 ' body accounts for 4.3%, and transposition secondary amine is not 0.25%, two phenyl ring N-methyl compound 0.13%.
Significantly precipitation does not all appear on the tube wall of the precondensation reactor of above embodiment.
Claims (6)
1. the continuous reaction process that thick MDA produces comprises the following steps:
A. aniline, hydrochloric acid, water are mixed in proportion, generate anilinechloride solution under the temperature control condition;
B. anilinechloride solution is as main flow, and formaldehyde solution enters jet mixer in proportion as time stream and carries out short mix; Mixed solution enters sectional precondensation tubular reactor, the reaction of proceed step by step precondensation; Molar ratio of material is aniline/hydrochloric acid/formaldehyde/water=1/0.3～1.0/0.2～0.49/4.5～6.0;
C. enter tubular type first inversion device after the heating of precondensation liquid and carry out translocation reaction, generate polyamines, enter second changer behind the reheat, make transposition complete;
D. condensated liquid obtains thick MDA through the neutralization washing after making with extra care.
2. technology according to claim 1 is characterized in that: the temperature of aniline salt acid solution is controlled at 20～40 ℃; The jet mixer pressure drop is 0.3～0.6MPa, and the volume ratio of anilinechloride solution and formaldehyde solution is 6～10/1, can once also can repeatedly add when adding formaldehyde.
3. technology according to claim 2 is characterized in that: the precondensation reaction divides three sections and carries out: first section, and material flow 5～10m/s in the tubular reactor, 0.5～2 second residence time; Second section, residence time of material is 30～60 seconds in the tubular reactor, and flow velocity is 0.5～1.5m/s, and temperature of reaction is 30～60 ℃; The 3rd section, material is having the reactor reaction of heat-exchanger rig, 1～10 minute residence time.
4. technology according to claim 3 is characterized in that: tubular type first inversion device is vertical, and residence time of material is 3～10 minutes, flow velocity 1～5cm/s, and temperature is 90～100 ℃; Second changer is horizontal, and residence time of material is 30～120 minutes, and temperature is 100～140 ℃.
5. technology according to claim 4 is characterized in that: the pressure reduction of jet mixer is 0.4MPa, and the volume ratio of anilinechloride solution and formaldehyde solution is 8～10: 1; First section tubular type precondensation reactor, material flow is greater than 8m/s, about 1 second residence time; 50 ℃ of temperature vertexs in second section tubular type precondensation reactor.
6. technology according to claim 5 is characterized in that: the temperature of first inversion device is 98 ℃, 5 minutes residence time; The temperature of second changer is 110 ℃, 90 minutes residence time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CNA2007100654227A CN101143828A (en) | 2007-04-13 | 2007-04-13 | Continuous reaction technique for producing crude MDA |
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| CNA2007100654227A CN101143828A (en) | 2007-04-13 | 2007-04-13 | Continuous reaction technique for producing crude MDA |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106467453A (en) * | 2016-08-31 | 2017-03-01 | 贝利化学（张家港）有限公司 | A kind of method that pipeline reactor synthesizes p-Methoxybenzoic acid |
| CN114315598A (en) * | 2020-09-29 | 2022-04-12 | 万华化学集团股份有限公司 | Preparation method of diphenylmethane series diamine and polyamine |
-
2007
- 2007-04-13 CN CNA2007100654227A patent/CN101143828A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106467453A (en) * | 2016-08-31 | 2017-03-01 | 贝利化学（张家港）有限公司 | A kind of method that pipeline reactor synthesizes p-Methoxybenzoic acid |
| CN106467453B (en) * | 2016-08-31 | 2018-10-16 | 贝利化学（张家港）有限公司 | A kind of method of pipeline reactor synthesis P-methoxybenzoic acid |
| CN114315598A (en) * | 2020-09-29 | 2022-04-12 | 万华化学集团股份有限公司 | Preparation method of diphenylmethane series diamine and polyamine |
| CN114315598B (en) * | 2020-09-29 | 2024-02-02 | 万华化学集团股份有限公司 | Preparation method of diphenyl methane series diamine and polyamine |
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Open date: 20080319 |