WO2022147939A1 - 一种制备二异氰酸酯的方法及其装置 - Google Patents

一种制备二异氰酸酯的方法及其装置 Download PDF

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WO2022147939A1
WO2022147939A1 PCT/CN2021/093995 CN2021093995W WO2022147939A1 WO 2022147939 A1 WO2022147939 A1 WO 2022147939A1 CN 2021093995 W CN2021093995 W CN 2021093995W WO 2022147939 A1 WO2022147939 A1 WO 2022147939A1
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reaction
phosgene
reactor
zone
diamine
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PCT/CN2021/093995
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English (en)
French (fr)
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陈斌
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安徽东至广信农化有限公司
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Priority to US17/326,376 priority Critical patent/US11542228B2/en
Publication of WO2022147939A1 publication Critical patent/WO2022147939A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C263/00—Preparation of derivatives of isocyanic acid
    • C07C263/10—Preparation of derivatives of isocyanic acid by reaction of amines with carbonyl halides, e.g. with phosgene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
    • B01J19/0066—Stirrers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/18—Stationary reactors having moving elements inside
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2601/00—Systems containing only non-condensed rings
    • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
    • C07C2601/16—Systems containing only non-condensed rings with a six-membered ring the ring being unsaturated

Definitions

  • the invention belongs to the field of organic chemical industry, and designs a method for preparing isocyanate and a device thereof, in particular to a low-temperature gas-phase high-efficiency reactor and a method for preparing isocyanate through gas-phase phosgenation process using the reactor.
  • diisocyanate products mainly include aromatic, aliphatic and alicyclic isocyanates. Aliphatic and alicyclic isocyanates are collectively referred to as ADI isocyanates.
  • ADI isocyanate varieties mainly include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), xylylene diisocyanate (XDI) , tetramethylxylylene diisocyanate (TMXDI) and so on.
  • the gas-phase phosgenation method to prepare diisocyanates was reported in the 1940s.
  • the gas-phase reaction process is often carried out in a tubular reactor, which has the characteristics of fast reaction rate and low phosgene retention.
  • the reaction in order to speed up the reaction rate, the reaction is carried out at high temperature, which not only causes the decomposition of phosgene at high temperature, the increase of chlorine-containing by-products, but also the cracking of diamines, which becomes monoamine compounds, and finally generates monofunctional isocyanate impurities.
  • the mixing is improper, such as when the mixing is slow, more polymerization by-products will be generated.
  • Patent CN105032307A discloses a dynamic self-cleaning reactor in which phosgene and diamine are heated to 250-500°C, and the mixing reaction is carried out by spraying in the upper part of the mixer. Adding scrapers, support shafts, mixers and other components to the lower part of the reaction nozzle can ensure the formation of a swirling flow in the reaction gas phase, and provide rotating power to the scraper, clean the sediment in the reactor, and prolong the operation period.
  • a reactor dominated by turbulent flow is used to strengthen mixing, so that the reactants react in a state of strong turbulent flow.
  • the inner diameter is 2.5 mm and the length is 17.5 mm.
  • the amine steam is sprayed into the reactor at a high speed through a nozzle.
  • HDI was prepared at a high temperature of 300-500 °C. Subsequent improvements transformed the simple cylindrical reactor into a Venturi-like mixer, a design that reduced the contact and backmixing of the reaction zone with the walls.
  • the prior art is the preparation of isocyanates in the gas phase, in which the reaction properties in the tubular reactor are improved by means of flow-related measures such as the addition of homogenizing elements in the reactor and the centering of the gas phase educts, and in this way the heating is carried out.
  • the amine and phosgene react rapidly to 300-600° C., thereby avoiding the formation of deposits in the reactor walls and the formation of polymeric secondary products that lead to shortening of the reactor.
  • Patent CN101735109B discloses a method for preparing organic isocyanates in a liquid phase by using an impinging flow reactor and a static mixer.
  • the impinging flow reactor includes an outer cylinder, the feeding nozzle is arranged at the upper part of the outer cylinder, and the discharge port is arranged at the bottom of the outer cylinder ; Dissolve organic primary amine and phosgene in the same inert organic solvent respectively, and add them into the outer cylinder through the feeding nozzle to carry out phosgenation reaction, so that the average residence time of the material does not exceed 30s;
  • the discharged material is introduced into the reaction from the feed port of the static mixer provided with the heat exchange device, and the average residence time of the material is less than 30min, resulting in crude organic isocyanate.
  • the method of the invention utilizes the good micro-mixing properties of the impingement flow reactor, improves the mixing efficiency of raw materials, reduces the production cost of isocyanate and improves the production capacity of isocyanate.
  • the reactor of the invention has a simple structure, reduces the risk of blockage by solids, is easy to seal, and reduces the risk of phosgene leakage.
  • the process of preparing diisocyanate by gas-phase phosgenation is a rapid reaction process. Often, in order to ensure the reaction speed, higher temperature reaction temperature and wall temperature are used, and the formation of chlorine-containing by-products and monofunctional isocyanate impurities cannot be avoided. Therefore, it is necessary to find a A method that enables efficient and rapid mixing of reactants and effective removal of reaction by-products and deposits.
  • the object of the present invention is to provide a kind of low temperature gas phase high efficiency reactor and adopt this reactor to prepare the method for diisocyanate by gas phase phosgenation process.
  • the phosgene and diamine reaction impact zone can be arranged in the reaction zone, and the mixing of the two raw materials can be strengthened through the impact zone, which can speed up the mixing reaction of the phosgene and the diamine raw materials.
  • the inert medium is continuously diluted to remove the reaction heat in time, reduce the production of reaction by-products under high temperature conditions, control the wall temperature of each area of the tubular shell to reduce the coke on the wall, improve the reaction yield, and prolong the operation period of the reaction equipment.
  • the present invention adopts following technical scheme:
  • the low-temperature gas-phase reactor for preparing diisocyanate of the present invention comprises upper and lower sections, the upper section is a rapid reaction heat transfer section, the lower section is a slow reaction heat preservation section, and the two sections of the reactor are both jacketed tube reactors with basically the same structure, And have their own independent jacket device, independent temperature control.
  • the upper rapid reaction heat transfer section includes a tubular shell, an external segmented jacket, and an air distribution device located on the top of the shell.
  • the shell is provided with at least one set of uniformly distributed feeding nozzles.
  • a group of the feeding nozzles includes at least one phosgene feeding nozzle and at least one diamine feeding nozzle, and the reaction materials are ejected through the nozzles and collide with each other in the middle impact zone to enhance the reaction effect.
  • the lower part of the impact zone is provided with a disc, and the diameter of the disc is smaller than the inner diameter of the tubular reactor. Its function is to prevent the mixture from directly entering the reaction section, so that the reaction mixture forms a turbulent flow, and adjusts the contact time between phosgene and amine.
  • a fan blade is arranged on the rotating shaft, and the fan blade quickly guides the reactant to the lower section during rotation.
  • the angle between the feed nozzle and the axial direction of the reactor is 90°, that is, it is placed horizontally.
  • the gas distribution device is located on the top of the shell, on the upper part of the feeding nozzle, and the upper surface of the gas distribution device has an air outlet device.
  • the inert medium is evenly distributed through the gas distribution device and is refracted to the impact reaction zone on the top of the shell, reducing the temperature and temperature of the reaction zone. concentration.
  • the lower section of the slow reaction and heat preservation section is basically the same type as the upper section of the reactor, but there is no air distribution device and feed nozzle, and the wind direction of the fan blades on the rotating shaft is opposite.
  • the phosgene and diamine feeds enter the shell and are dispersed in the form of nozzles, the dispersed phase collides between the two feed pipes, and the turbulent impact zone generated by the impinging flow is located in the steady state region between the two feed pipes.
  • the diameter of the impact reaction zone d1 (0.2 ⁇ 0.6)D
  • D is the inner diameter of the tubular shell
  • d can be understood as the diameter of the circular area formed by the nozzle or the distance between the front ends of the two nozzles in alignment
  • D is 0.5 to 1 m, and can also be 0.6 m, 0.7 m, 0.8 m, and 0.9 m.
  • the distance between the disc and the plane of the impact zone formed by the nozzle is 10 to 100 mm;
  • the speed at which phosgene and diamine enter the impact zone are the same and both are 10-50 m/s, preferably 15-45 m/s, more preferably 20-40 m/s, It is more preferably 25 to 35 m/sec, and more preferably 30 m/sec.
  • the average residence time of the material in the impact zone is 0.01-0.5 seconds, preferably 0.05-0.4 seconds, more preferably 0.1-0.3 seconds, more preferably 0.15-0.3 seconds, more preferably 0.2-0.3 seconds, more preferably 0.25-0.3 seconds.
  • tubular shell is provided with 1-4 phosgene and 1-4 diamine feeding nozzles, preferably 2-3 phosgene and 2-3 diamine feeding nozzles, wherein phosgene feeds
  • phosgene feeds The nozzles and the diamine feed nozzles are alternately spaced and distributed uniformly and symmetrically in the reactor shell.
  • the distance between the air distribution device and the top of the tubular casing is 10-100 mm, preferably 50-100 mm, more preferably 60-100 mm, more preferably 70-100 mm, more preferably 80-100 mm, more preferably 80-90 mm.
  • the distance between the air distribution device and the steady-state impact zone is 10-200mm, preferably 50-200mm, more preferably 50-180mm, more preferably 100-150mm, and can also be 110mm, 120mm, 130mm and 140mm.
  • the speed of refraction at the top of the shell to the impact reaction zone is 0.1-8 m/s, preferably 0.5-6 m/s, more preferably 1-4 m/s, or 1.5 m/s, 2 m/s, 2.5 m/s.
  • the size of the nozzle is optional to control the molar ratio of the feed amine and phosgene to be 1:1.2-5, preferably 1:1.3-4, more preferably 1:1.5-3, preferably 1:1.6-2, preferably 1 : 1.8 to 2. Excess phosgene can ensure the complete reaction of the amine, and the excess phosgene can be separated and recovered for recycling in the later stage.
  • the outer segmented jacket of the tubular shell is divided into an upper rapid reaction heat transfer section and a lower slow reaction heat preservation section.
  • the upper rapid reaction heat transfer section keeps the shell wall temperature at 200 to 300 °C, preferably 250 to 290 °C, more preferably 260 to 280 °C, and can also be 270 °C;
  • the lower slow reaction heat preservation section maintains the shell wall temperature as 150 to 300°C, preferably 160 to 290°C, more preferably 170 to 280°C, more preferably 180 to 260°C.
  • the temperatures of the above two-stage reactors are determined according to different reactants.
  • the distance of the rapid reaction heat transfer section at the upper part of the segmented jacket outside the tubular shell is 500-2000mm, preferably 600-2000mm, preferably 800-1900mm, preferably 1000-1800mm, preferably 1200-1700mm, preferably 1500-1600mm.
  • the distance of the lower slow reaction holding section is 1000-7000mm, preferably 2000-7000mm, preferably 3000-7000mm, preferably 3500-6500mm, preferably 4000-6000mm, and can also be 4500mm, 5000mm, 5500mm.
  • heat transfer medium in the outer segmented jacket of the tubular shell, such as one of heat transfer oil, steam, molten salt and the like.
  • the upper and lower reactors are connected by a check valve to ensure that the reactants will not be back mixed to cause serious side reactions.
  • the rotating shafts of the upper and lower sections are individually controlled, and the rotation speed can be controlled to an appropriate speed to ensure the residence time and the reaction effect.
  • the upper fan ensures that the airflow goes down, and the lower part controls the airflow to slightly ascend, or does not affect the airflow, or controls the airflow to descend, that is, the airflow is controlled by forward or reverse rotation, which is reversed with the airflow in the upper segment, which can increase the dwell time and accurately. Control the reaction to ensure the reaction effect.
  • the air distribution equipment can be one of the slot-disk type, the tube type, the air-lifting cap type, and the vane type.
  • the inert medium is a mixture of one or more of nitrogen, argon, helium, radon, carbon dioxide, and carbon monoxide.
  • the present invention also provides a method for preparing diisocyanate using the above-mentioned low-temperature gas-phase high-efficiency reactor, the method comprising:
  • the inert medium in the gas distribution equipment in step b) is a mixture of one or more of nitrogen, argon, helium, radon, carbon dioxide and carbon monoxide.
  • reaction pressure in step c) or d) tubular reactor is 0.2 ⁇ 10bar, preferably 1 ⁇ 9bar, preferably 1 ⁇ 8bar, also can be 2bar, 3bar, 4bar, 5bar, 6bar or 7bar; Above-mentioned pressure is absolute pressure.
  • the amine to phosgene feed molar ratio is 1:1.2-5, preferably 1:1.3-4, more preferably 1:1.5-3, preferably 1:1.6-2, preferably 1:1.8-2.
  • step d) quenching zone can use conventional equipment such as washing tower, the gaseous reaction mixture is cooled by 100 ⁇ 200 °C (solvent temperature can also be 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C , 170 ° C, 180 ° C, 190 ° C), the solvent is cooled and absorbed, so that the isocyanate is selectively transferred to the washing solution; the solvent can be a non-reactive (inert relative to the isocyanate product system) solvent that meets the temperature and dissolution conditions, such as Halogen-substituted hydrocarbons, such as conventional chlorobenzene, dichlorobenzene, etc., can also use isocyanates, such as the same isocyanates as the product, as the quenching solvent.
  • solvent temperature can also be 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C , 170 ° C, 180 ° C
  • the isocyanate mixture after quenching is separated into isocyanate solution and gas components; the gas components enter the tail gas treatment link for absorption and recycling; the isocyanate enters the rectifying tower to separate the isocyanate product.
  • the diamine raw material used in the present invention is selected from toluenediamine, methylenediphenylamine, 1,6-hexanediamine, isophoronediamine, cyclohexanediamine, 1,4-butanediamine, 1,6-hexanediamine, 5-Diamino-2-methylpentane, 1,4-diaminocyclohexane, m-xylylenediamine, 4,4'-diaminodicyclohexylmethane, diaminobenzene, naphthalenediamine etc.; the above-mentioned diamines with no defined positions include all possible structures of this structure that may be substituted with two amino groups.
  • the specific device of the present invention can carry out the reaction at a lower temperature, avoiding by-products generated by high temperature, and the specific reactor structure avoids the generation of coke, long-term operation is unobstructed, and no cleaning is required; compared with the solvent method, the reaction is fast. , The advantages of high mixing efficiency.
  • FIG. 1 Schematic diagram of a single group of feed nozzle reactors
  • FIG. 2 Schematic diagram of the setting structure of the feeding nozzle
  • FIG. 3 Schematic diagram of two-group feed nozzle reactor
  • the numbers in the figure represent: 1-gas distribution device, 21-phosgene feed nozzle, 22-diamine feed nozzle, 3-reactor, 4-rotating shaft, 5-flow-promoting blade, 6-reactor shell Body, 7-tubular shell external segmented jacket-upper rapid reaction heat transfer section, 8 and 9-connecting device of upper rapid reaction heat transfer section of reactor and lower slow reaction heat preservation section, 10-disc.
  • the preparation of the diisocyanate reactor includes: in the tubular reactor 3, the phosgene feed tube 21 entering the reaction tube in the upper region of the reaction tube and the diamine feed tube are introduced into the side corresponding to the same position 22.
  • the central area of the two feed pipes is the reaction and impact area. Due to the continuous and stable feeding, the steady state of this area is ensured, and the phosgene and diamine carry out mutual collision and mixing reaction in this area.
  • a gas distribution device 1 with inert gas on the top of the tubular shell After the inert gas entering the feed pipe passes through the gas distribution device, it is evenly distributed and reaches the top of the tubular shell, and then re-refracted to the impact reaction zone to reduce the reaction rate. zone temperature and concentration.
  • a jacket in the outer shell of the tubular reactor which is divided into upper and lower parts, and different temperatures are used to transfer heat respectively.
  • the upper part is the rapid reaction heat removal section 7, and the lower part is the slow reaction heat preservation section.
  • Figure, but its structure is basically the same as the previous paragraph, except that there is no air distribution device and feeding device.
  • the crude diisocyanate gas phase is obtained through the tubular reactor reaction, and reaches the quenching zone.
  • the crude diisocyanate mixture is recycled and absorbed by the solvent in the quenching zone, the crude diisocyanate crude product is obtained, and then the product is purified and rectified.
  • the product of diisocyanate is obtained, and the gas component enters the tail gas treatment part for absorption and circulation.
  • FIG. 3 is a reactor with two sets of feed nozzles shown in FIG. 2 .
  • a reactor as shown in Figures 1-2 was used. There are 2 phosgene feeding nozzles and 2 diamine feeding nozzles on the tubular reactor. The phosgene and diamine feeding nozzles are arranged alternately and evenly at horizontal intervals. The angle is 90°C.
  • the average residence time of the two materials in the impact zone was 0.2 seconds. D is 0.5 meters.
  • the distance between the tubular gas distribution equipment and the top of the tubular shell is 80 mm, and the distance between the steady-state impact zone is 100 mm, the inert medium is nitrogen, and the speed of refraction to the impact reaction zone is 4 m/s.
  • the upper part of the tubular shell rapidly reacts with the heat transfer section, keeping the shell wall temperature at 280°C, and the distance between the heat transfer section is 1500mm.
  • the lower slow reaction insulation section keeps the shell wall temperature at 200°C, the insulation section distance is 6000mm, and the jacket medium is heat-conducting oil.
  • 1,6-Hexamethylene hexanediamine (HDA) and phosgene are preheated to 250°C, and nitrogen is preheated to 200°C. Adjust the nozzle diameter and control the HDA:phosgene molar ratio to be 1:1.5. After the phosgene and HDA are distributed through the nozzle, effective micro-mixing is carried out in the impact zone, and nitrogen gas passes through the impact reaction zone from above to take away excess heat. After the gas-phase mixture passes through the impingement mixing reaction zone, it is further reacted along the tubular reactor to obtain a gas-phase diisocyanate mixture, wherein the reaction pressure in the tubular reactor is 1 bar.
  • the crude diisocyanate mixture is recycled and absorbed through the solvent chlorobenzene at a temperature of 130° C. to obtain a liquid-phase crude product. Removing light/heavy components in a rectifying tower to obtain a diisocyanate product.
  • the gas enters the tail gas treatment device.
  • the content of HDI product obtained by the rectification column is 99.8%
  • the chromaticity is less than or equal to 12HAZEN (Apha) (much lower than the commercial product)
  • the conversion rate of HDA is 98.9%.
  • a reactor as shown in Figures 1-2 was used. There are 2 phosgene feeding nozzles and 2 diamine feeding nozzles on the tubular reactor. Phosgene and diamine feeding nozzles are alternately and evenly spaced horizontally. The angle is 45°C.
  • the average residence time of the two materials in the impact zone was 0.3 seconds. D is 0.7 meters.
  • the distance between the tubular gas distribution equipment and the top of the tubular shell is 60mm, and the distance from the steady-state impact zone is 200mm, the inert medium is nitrogen, and the speed of refraction to the impact reaction zone is 4m/s.
  • the upper part of the tubular shell rapidly reacts with the heat transfer section, keeping the shell wall temperature at 280°C and the distance between the heat transfer section at 1200mm.
  • the lower slow reaction insulation section keeps the shell wall temperature at 220°C, the insulation section distance is 5000mm, and the jacket medium is heat-conducting oil.
  • Isophorone diamine (IPDA) and phosgene distribution are preheated to 260°C, and nitrogen is preheated to 170°C. Adjust the nozzle diameter and control the molar ratio of IPDA:phosgene to 1:1.3. After the phosgene and IPDA are distributed through the nozzle, effective micro-mixing is carried out in the impact zone, and nitrogen gas passes through the impact reaction zone from above to take away excess heat. After passing through the impingement mixing reaction zone, the gas-phase mixture is further reacted along the tubular reactor to obtain a gas-phase diisocyanate mixture, wherein the reaction pressure in the tubular reactor is 1.5 bar.
  • the crude diisocyanate mixture is recycled and absorbed by using chlorobenzene at a temperature of 130° C. to obtain a liquid-phase crude product. Removing light/heavy components in a rectifying tower to obtain a diisocyanate product.
  • the gas enters the tail gas treatment device.
  • the IPDI product content is 99.5% obtained through the rectification column, the chromaticity is less than or equal to 20HAZEN (Apha) (much lower than the commercial product), and the IPDA conversion rate is 98.9%.
  • the machine was shut down for maintenance. No obvious coke was found at the outlet of the phosgene and diamine feed pipes and the inner wall of the tubular reactor. The equipment was in good condition and did not affect the continued operation of the reaction.
  • Reactors as shown in Figures 2-3 were used. There are 2 phosgene feeding nozzles and 2 diamine feeding nozzles on the tubular reactor. The phosgene and diamine feeding nozzles are arranged alternately and evenly at horizontal intervals. The angle is 90°C. There are two groups of such components shown in Fig. 2, the second group is located in the middle section of the reactor.
  • the speed at which phosgene enters the impact zone is 30 m/s
  • the speed at which diamine enters the impact zone is 30 m/s.
  • the distance from the impact area is 100mm.
  • the average residence time of the two materials in the impact zone was 0.3 seconds.
  • D is 1 meter.
  • the distance between the tubular gas distribution equipment and the top of the tubular shell is 80mm, and the distance from the steady-state impact zone is 100mm, the inert medium is nitrogen, and the speed of refraction to the impact reaction zone is 8 m/s.
  • the upper part of the tubular shell rapidly reacts to the heat transfer section, keeping the shell wall temperature at 280°C and the distance of the heat transfer section at 2000mm.
  • the lower slow reaction insulation section keeps the shell wall temperature at 220°C, the insulation section distance is 7000mm, and the jacket medium is heat-conducting oil.
  • Isophorone diamine (IPDA) and phosgene distribution are preheated to 260°C, and nitrogen is preheated to 170°C. Adjust the nozzle diameter and control the molar ratio of IPDA:phosgene to 1:1.3. After the phosgene and IPDA are distributed through the nozzle, effective micro-mixing is carried out in the impact zone, and nitrogen gas passes through the impact reaction zone from above to take away excess heat. After passing through the impingement mixing reaction zone, the gas-phase mixture is further reacted along the tubular reactor to obtain a gas-phase diisocyanate mixture, wherein the reaction pressure in the tubular reactor is 3 bar.
  • the crude diisocyanate mixture is recycled and absorbed by using chlorobenzene at a temperature of 130° C. to obtain a liquid-phase crude product. Removing light/heavy components in a rectifying tower to obtain a diisocyanate product.
  • the gas enters the tail gas treatment device.
  • the IPDI product content is 99.6% obtained through the rectification column, the chromaticity is less than or equal to 21HAZEN (Apha) (much lower than the commercial product), and the IPDA conversion rate is 99.1%.

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Abstract

一种低温气相法制备二异氰酸酯的反应器及方法，管式反应器包括管式壳体、外部夹套及位于壳体顶部的布气设备，壳体上设置有至少一组均匀分布的进料喷嘴，一组进料喷嘴包括至少一个光气进料喷嘴和至少一个二胺进料喷嘴，反应物料通过喷嘴喷出后在中部撞击区相互撞击，增强反应效果，布气设备位于壳体顶部、进料喷嘴上部，惰性介质通过布气设备均匀分布后在壳体顶部折射至撞击反应区，降低反应区温度及浓度，通过反应器，可以强化光气及胺类混合，惰性介质连续稀释，及时移走反应放出热量，减少高温下副产的生成，控制管式壳体各区域壁面温度减少壁面结焦物，提高反应收率，延长反应设备的运作周期。

Description

一种制备二异氰酸酯的方法及其装置 技术领域
本发明属于有机化工领域，设计异氰酸酯的制备方法及其装置，具体涉及一种低温气相高效反应器以及采用该反应器通过气相光气化过程制备异氰酸酯的方法。
背景技术
异氰酸酯是一类含有-N＝C＝O官能团的有机化合物，二异氰酸酯是指含有两个该官能团的化合物，二异氰酸酯一般都具有很高的反应活性，极易与含有活泼氢的化合物发生反应，是一种重要的有机合成中间体。自1849年Wurtz首次制备出烷基异氰酸酯以来，人类一直在探索各种具有特殊结构和性能的异氰酸酯产品以及开发各种制备异氰酸酯的方法。
目前二异氰酸酯产品主要包括芳香族类、脂肪族类和脂环族类，脂肪族类和脂环族类异氰酸酯统称为ADI类异氰酸酯，近年来ADI类异氰酸酯产品的需求加大，该类产品发展较快。ADI类异氰酸酯品种主要有异佛尔酮二异氰酸酯(IPDI)、六亚甲基二异氰酸酯(HDI)、4,4'-二环己基甲烷二异氰酸酯(H12MDI)、苯二甲基二异氰酸酯(XDI)、四甲基苯二亚甲基二异氰酸酯(TMXDI)等。
气相光气化法来制备二异氰酸酯在20世纪40年代就有报道，气相反应过程常常在管式反应器内进行，其具有反应速率快，光气滞留量低的特点。传统气相反应，为了加快反应速率，均采用高温下反应，不仅造成高温下光气分解，含氯副产物增加，而且会发生二胺裂解，变成单胺类化合物，最终生成单官能团异氰酸酯杂质。同时，若混合不当，如混合缓慢时，则生成较多聚合副产物。这些副产物由于反应器内壁壁面温度控制不佳，会进一步聚合，形成高粘度焦油物质，造成器壁内部挂壁结焦、结块，最终堵塞反应器，特别是物料在第一接触点处更易产生结焦物，进而导致混合流场的逐步恶化，缩短了反应器的运行周期。因此，一方面需要低温下反应，减少含氯副产物和单官能团异氰酸酯生成。另一方面，采用高混合效率的反应器，有效提高反应收率，减少副反应发生的几率，第三方面，控制温度的惰性气体在反应撞击区稀释及管式壳体各个区域壁面温度控制， 以避免在反应器内固体结焦物的生成，有效减少不可避免的反应沉积物，延长反应器运行周期。
专利CN105032307A公开了一种动态自清理反应器，光气及二胺加热至250～500℃，先将在混合器中上部通过喷射进行混合反应。在反应喷嘴下部增加刮片、支撑轴、混合器等部件，可以保证反应气相形成旋流，并给刮片提供旋转动力，清理反应器的沉积物，延长运行周期。还有现有技术采用湍流占主导地位的反应器来加强混合，使反应物在强湍流状态下反应，其内径为2.5mm，长度为17.5mm，胺蒸汽通过喷嘴高速的喷入到反应器内，在300～500℃高温下制备HDI。后续的改进将简单的圆筒形反应器改善为类似文丘里混合器，这种设计可以减少反应区与器壁的接触和返混。现有技术有在气相中制备异氰酸酯，方法中通过与流动相关的措施如在反应器中加入均化元件以及确定气相离析物的中心，提高管式反应器内的反应特性，以此形式使加热到300～600℃的胺和光气快速反应，从而避免反应器壁面中沉积物和导致反应器缩短的聚合次级产物的形成。
专利CN101735109B公开了一种采用撞击流反应器和静态混合器在液相中制备有机异氰酸酯的方法，撞击流反应器包括外筒，进料喷嘴设置在外筒的上部，出料口设置在外筒的底部；将有机伯胺和光气分别溶解在相同的惰性有机溶剂中，通过进料喷嘴加入外筒内，进行光气化反应，使物料平均停留时间不超过30s；将从撞击流反应器出料口排出的物料从设置有换热装置的静态混合器进料口引入反应，物料平均停留时间小于30min，生成有机异氰酸酯粗品。本发明的方法利用撞击流反应器良好的微观混合性质，改善原料的混合效率，降低异氰酸酯生产成本并提高异氰酸酯生产能力。本发明反应器结构简单，降低了固体物堵塞的危险；易于密封，减少光气泄漏的危险。
气相光气化制备二异氰酸酯的过程是一快速反应过程，往往为了保证反应速度，采用较高温度反应温度及壁面温度，无法避免含氯副产物和单官能团异氰酸酯杂质的形成，因此需要寻找一种能够使反应物高效快速混合且有效除去反应副产物及沉积物的方法。
发明内容
本发明的目的在于，提供一种低温气相高效反应器以及采用该反应器通过气 相光气化过程制备二异氰酸酯的方法。其可在反应区域设置光气及二胺反应撞击区，通过撞击区强化两种原料混合，可以加快光气及二胺原料混合反应。惰性介质连续稀释，及时移走反应放出热量，减少高温情况下反应副产物的产生，控制管式壳体各个区域壁面温度减少壁面结焦物，提高反应收率，延长反应设备的运作周期。
本发明采用以下技术方案：
本发明的制备二异氰酸酯的低温气相反应器包括上下两段，上段为急速反应移热段，下段为慢速反应保温段，两段反应器类型均为基本相同结构的夹套管式反应器，且具有各自独立的夹套装置，独立控温。
上段急速反应移热段，包括管式壳体及外部分段式夹套、位于所述壳体顶部的布气设备，所述壳体上设置有至少一组均匀分布的进料喷嘴。一组所述进料喷嘴包括至少一个光气进料喷嘴和至少一个二胺进料喷嘴，反应物料通过喷嘴喷出后在中部撞击区相互撞击，增强反应效果。撞击区下部设置圆盘，圆盘直径小于管式反应器内径，其作用为阻止混合物直接进入反应段，使反应混合物形成乱流，调节光气与胺的接触时间，由于其连接旋转轴，因此具有扰流作用，使混合气沿器壁下行。此时为了将充分接触的反应物迅速由急速反应移热段传递至慢速反应保温段，在旋转轴上设置扇叶，转动时扇叶将反应物迅速导流至下段。所述进料喷嘴与反应器轴向夹角为90°，即水平放置。所述布气设备位于所述壳体顶部，进料喷嘴上部，布气装置上表面具有出气装置，惰性介质通过布气设备均匀分布后在壳体顶部折射至撞击反应区，降低反应区温度及浓度。管式壳体外部分段式夹套中存在移热介质，有效控制壳体壁面温度。
下段慢速反应保温段，与上段反应器类型基本相同，但是不设置布气装置和进料喷嘴，且转轴上扇叶风向相反。
进一步地，光气和二胺进料进入壳体内部采用喷嘴形式进行分散，分散相在两进料管中间撞击，撞击流产生的湍动撞击区位于两进料管之间的稳态区域内，撞击反应区的直径d1＝(0.2～0.6)D,D为管式壳体的内径，d可以理解为喷嘴所形成圆形区域的直径或者处于对位的两个喷嘴前端之间的距离，优选d1＝(0.3～0.6)D，更优选d1＝(0.4～0.6)D，更优选d1＝(0.5～0.6)D，更优选d1＝0.6D。
进一步地，圆盘直径d2＝(0.6～0.9)D，优选d2＝(0.7～0.9)D，更优选 d2＝(0.75～0.9)D，更优选d2＝(0.8～0.9)D，更优选d2＝(0.85～0.9)D。D为0.5～1米，还可以为0.6米、0.7米、0.8米、0.9米。
圆盘距离喷嘴形成的撞击区平面10～100mm；还可以为20mm、30mm、40mm、50mm、60mm、70mm、80mm、90mm。
进一步地，光气和二胺进料喷嘴中光气和二胺进入撞击区的速度相同且均为10～50米/秒，优选15～45米/秒，更优选20～40米/秒，更优选25～35米/秒，更优选30米/秒。物料在撞击区内平均停留时间为0.01～0.5秒，优选0.05～0.4秒，更优选0.1～0.3秒，更优选0.15～0.3秒，更优选0.2～0.3秒，更优选0.25～0.3秒。
进一步地，管式壳体上设置有1～4个光气和1～4个二胺进料喷嘴，优选2～3个光气和2～3个二胺进料喷嘴，其中光气进料喷嘴与二胺进料喷嘴交替间隔且均匀、对称分布在反应器壳体，优选光气与二胺进料喷嘴数量相同，优选数量均为2。
进一步地，布气设备和管式壳体顶部的间距为10～100mm，优选50～100mm，更优选60～100mm，更优选70～100mm，更优选80～100mm，更优选80～90mm。布气设备和稳态撞击区的间距为10～200mm，优选50～200mm，更优选50～180mm，更优选100～150mm，还可以为110mm、120mm、130mm、140mm。
进一步地，惰性介质通过布气设备均匀分布后在壳体顶部折射至撞击反应区的速度为0.1～8米/秒，优选0.5～6米/秒，更优选1～4米/秒，还可以为1.5米/秒、2米/秒、2.5米/秒。
进一步地，喷嘴大小可选，以控制进料胺与光气的摩尔比为1:1.2～5，优选1：1.3～4，更优选1：1.5～3，优选1:1.6～2，优选1:1.8～2。过量光气可以保证胺的完全反应，而且后期可以分离回收过量光气循环使用。
进一步地，管式壳体外部分段式夹套，分为上部急速反应移热段、下部慢速反应保温段。其中上部急速反应移热段，保持壳体壁面温度为200～300℃，优选250～290℃，更优选260～280℃，还可以为270℃；下部慢速反应保温段保持壳体壁面温度为150～300℃，优选160～290℃，更优选170～280℃，更优选180～260℃。上述两段反应器的温度均根据不同反应物进行确定。
进一步地，管式壳体外部分段式夹套上部急速反应移热段距离500～2000mm，优选600～2000mm，优选800～1900mm，优选1000～1800mm，优选1200～1700mm， 优选1500～1600mm。下部慢速反应保温段距离1000～7000mm，优选2000～7000mm，优选3000～7000mm，优选3500～6500mm，优选4000～6000mm，还可以为4500mm，5000mm，5500mm。
进一步地，管式壳体外部分段式夹套中存在移热介质，例如导热油、蒸汽、熔盐等其中一种。
进一步地，上段、下段反应器之间通过止回阀连接，保证反应物不会返混导致严重的副反应。
进一步地，上段、下段的转轴单独控制，可以控制转速至合适的速度以保证停留时间、反应效果。上段风扇保证气流向下行，下段控制气流微弱上行、或者不影响气流，或者控制气流下行，即通过正向旋转或反向旋转实现对气流的控制，与上段气流形成逆向，可以增加停留时间，精确控制反应进行，保证反应效果。
进一步地，布气设备可以是槽盘式、管式、升气帽式、叶片式中一种。
进一步地，惰性介质是氮气、氩气、氦气、氡气、二氧化碳、一氧化碳中一种或多种的混合物。
本发明还提供了采用上述的低温气相高效反应器制备二异氰酸酯的方法，该方法包括：
a)将光气及二胺分别进行加热气化，保证进料喷嘴中反应进料温度为200～300℃；
b)将布气设备中惰性介质进行加热，保证惰性介质在壳体顶部折射温度为150～250℃；
c)光气和二胺经过喷嘴分布后，在撞击区进行有效微观混合，惰性介质从上穿过撞击反应区，带走多余热量；
d)气相混合物经过撞击混合、上段反应区后，沿着管式反应器中进一步反应，得到气相二异氰酸酯混合物；然后到骤冷区，通过溶剂对粗二异氰酸酯混合物循环吸收，得到液相粗产品；再经过精馏塔中除去轻/重组分，得到二异氰酸酯产品。
其中步骤b)中布气设备中惰性介质是氮气、氩气、氦气、氡气、二氧化碳、一氧化碳中一种或多种的混合物。
其中步骤c)或d)管式反应器中反应压力为0.2～10bar，优选1～9bar，优选 1～8bar，还可以为2bar、3bar、4bar、5bar、6bar或7bar；上述压力为绝对压力。
胺与光气进料摩尔比为1:1.2～5，优选1：1.3～4，更优选1：1.5～3，优选1:1.6～2，优选1:1.8～2。
其中步骤d)骤冷区可以采用现有技术常规的设备如洗涤塔，气态反应混合物被100～200℃(溶剂温度还可以为110℃、120℃、130℃、140℃、150℃、160℃、170℃、180℃、190℃)的溶剂降温吸收，使异氰酸酯选择性地转移至洗涤溶液中；溶剂可以为符合温度、溶解条件的非反应性(相对于异氰酸酯产物体系惰性)的溶剂，如卤素取代的烃类，具体比如常规的氯苯、二氯苯等，也可以使用异氰酸酯，比如与产物相同的异氰酸酯作为骤冷溶剂。
骤冷后的异氰酸酯混合物被分离为异氰酸酯溶液、气体组分；其中气体成分进入尾气处理环节，进行吸收、循环利用；异氰酸酯进入精馏塔分离出异氰酸酯产品。
本发明采用的二胺原料选自甲苯二胺、亚甲基二苯胺、1,6-己二胺、异佛尔酮二胺、环己烷二胺、1,4-丁二胺、1,5-二氨基-2-甲基戊烷、1,4-二氨基环己烷，间苯二亚甲基二胺，4,4’-二氨基二环己基甲烷、二氨基苯、萘二胺等；上述没有限定位置的二胺包括该结构的任意可被两个氨基取代的所有可能的结构。
本发明特定的装置可以在较低温度下进行反应，避免了高温产生的副产物，此外特定的反应器结构避免结焦的产生，长期运行无障碍，不需要进行清洁；与溶剂法相比具有反应快速、混合效率高等优点。
附图说明
图1单组进料喷嘴反应器示意图
图2进料喷嘴设置结构示意图
图3双组进料喷嘴反应器示意图
其中，图中编号分别表示：1-布气装置，21-光气进料喷嘴，22-二胺进料喷嘴，3-反应器，4-转轴，5-促流叶片，6-反应器壳体，7-管式壳体外部分段式夹套-上部急速反应移热段，8和9-反应器上部急速反应移热段与下部慢速反应保温段连接装置，10-圆盘。
具体实施方式
为了使本发明的目的、技术方案及优点更加清楚明白，以下通过实施例，并结合附图，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本发明，并不用于限定本发明。
除非另有定义，本文所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。本文中在本发明的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本发明。
如图1-2所示，制备二异氰酸酯反应器包括：管式反应器3中，在反应管上部区域进入反应管的光气进料管21和同样位置对应的一侧引入二胺进料管22，两个进料管中心区域为反应撞击区，由于进料连续稳定，保证该区域的稳态，光气和二胺在此区域中进行相互撞击混合反应。
其中，在管式壳体顶部有惰性气体的布气设备1，在进料管进入的惰性气体经过布气设备后，均匀分布到达管式壳体顶部后，重新折射至撞击反应区，降低反应区温度及浓度。在管式反应器外壳体有夹套，分为上下两个部分，分别采用不同温度移热，上部为急速反应移热段7，下部为慢速反应保温段，下部并未给出具体的附图，但是其结构与上段基本相同，除了没有布气装置和进料装置。
其中，经过管式反应器反应得到粗二异氰酸酯气相，到达骤冷区，在骤冷区使用溶剂对粗二异氰酸酯混合物循环吸收后，得到粗二异氰酸酯粗产品，然后进行产品精制精馏塔，脱除产品中轻重组分，得到二异氰酸酯的产品，气体组分进入尾气处理部分进行吸收、循环。
图3为具有两组图2所示进料喷嘴的反应器。
实施例1
采用如图1～2所示的反应器。管式反应器上光气进料喷嘴有2个，二胺进料喷嘴有2个，光气与二胺进料喷嘴交替均匀水平间隔设置，相邻两组进料喷嘴所在平面的轴向夹角为90℃。其中撞击反应区的直径d1＝0.6D,光气进入撞击区的速度为20米/秒，二胺进入撞击区的速度为20米/秒。圆盘直径d2＝0.7D，距离撞击区100mm。两种物料在撞击区内平均停留时间为0.2秒。D为0.5米。管式布气设备，和管式壳体顶部的间距为80mm，和稳态撞击区的间距为100mm， 惰性介质为氮气，折射至撞击反应区的速度为4米/秒。管式壳体上部急速反应移热段，保持壳体壁面温度为280℃，移热段距离1500mm。下部慢速反应保温段保持壳体壁面温度为200℃，保温段距离6000mm，其中夹套介质均为导热油。
制备二异氰酸酯HDI(1,6-六亚甲基二异氰酸酯)
1,6-六亚甲基已二胺(HDA)、光气分布预热至250℃，氮气预热温度至200℃。调整喷嘴管径，控制HDA：光气摩尔比为1:1.5，光气和HDA经过喷嘴分布后，在撞击区进行有效微观混合，氮气从上穿过撞击反应区，带走多余热量。气相混合物经过撞击混合反应区后，沿着管式反应器中进一步反应，得到气相二异氰酸酯混合物，其中管式反应器中反应压力为1bar。然后到骤冷区通过溶剂氯苯在130℃温度下对粗二异氰酸酯混合物循环吸收，得到液相粗产品。再经过精馏塔中除去轻/重组分，得到二异氰酸酯产品。气体进入尾气处理装置。
在该实施例中，通过精馏塔得到HDI产品含量99.8％，色度≤12HAZEN(Apha)(远低于市售产品)，HDA转化率为98.9％。经过长周期运行，在开车运行1个月之后，停车检修，光气、二胺进料管出口及管式反应器内壁均未见明显结焦物，设备状态良好，不影响反应的继续运转。
实施例2
采用如图1～2所示的反应器。管式反应器上光气进料喷嘴有2个，二胺进料喷嘴有2个，光气与二胺进料喷嘴交替均匀间隔水平设置，相邻两组进料喷嘴所在平面的轴向夹角为45℃。其中撞击反应区的直径d1＝0.65D,光气进入撞击区的速度为18米/秒，二胺进入撞击区的速度为18米/秒。两种物料在撞击区内平均停留时间为0.3秒。D为0.7米。管式布气设备，和管式壳体顶部的间距为60mm，和稳态撞击区的间距为200mm，惰性介质为氮气，折射至撞击反应区的速度为4米/秒。管式壳体上部急速反应移热段，保持壳体壁面温度为280℃，移热段距离1200mm。下部慢速反应保温段保持壳体壁面温度为220℃，保温段距离5000mm，其中夹套介质均为导热油。
制备二异氰酸酯IPDI(异佛尔酮二异氰酸酯)
异佛尔酮二胺(IPDA)、光气分布预热至260℃，氮气预热温度至170℃。调整喷嘴管径，控制IPDA：光气摩尔比为1:1.3，光气和IPDA经过喷嘴分布后，在撞击区进行有效微观混合，氮气从上穿过撞击反应区，带走多余热量。气相混 合物经过撞击混合反应区后，沿着管式反应器中进一步反应，得到气相二异氰酸酯混合物，其中管式反应器中反应压力为1.5bar。然后到骤冷区使用氯苯在130℃温度下对粗二异氰酸酯混合物循环吸收，得到液相粗产品。再经过精馏塔中除去轻/重组分，得到二异氰酸酯产品。气体进入尾气处理装置。
在该实施例中，通过精馏塔得到IPDI产品含量99.5％，色度≤20HAZEN(Apha)(远低于市售产品)，IPDA转化率为98.9％。经过开车运行3个月之后，停车检修，光气、二胺进料管出口及管式反应器内壁均未见明显结焦物，设备状态良好，不影响反应的继续运转。
实施例3
采用如图2～3所示的反应器。管式反应器上光气进料喷嘴有2个，二胺进料喷嘴有2个，光气与二胺进料喷嘴交替均匀水平间隔设置，相邻两组进料喷嘴所在平面的轴向夹角为90℃，这种图2所示的部件共两组，第二组位于反应器中段。其中撞击反应区的直径d1＝0.6D,光气进入撞击区的速度为30米/秒，二胺进入撞击区的速度为30米/秒。圆盘直径d2＝0.6D，距离撞击区100mm。两种物料在撞击区内平均停留时间为0.3秒。D为1米。管式布气设备，和管式壳体顶部的间距为80mm，和稳态撞击区的间距为100mm，惰性介质为氮气，折射至撞击反应区的速度为8米/秒。管式壳体上部急速反应移热段，保持壳体壁面温度为280℃，移热段距离2000mm。下部慢速反应保温段保持壳体壁面温度为220℃，保温段距离7000mm，其中夹套介质均为导热油。
制备二异氰酸酯IPDI(异佛尔酮二异氰酸酯)
异佛尔酮二胺(IPDA)、光气分布预热至260℃，氮气预热温度至170℃。调整喷嘴管径，控制IPDA：光气摩尔比为1:1.3，光气和IPDA经过喷嘴分布后，在撞击区进行有效微观混合，氮气从上穿过撞击反应区，带走多余热量。气相混合物经过撞击混合反应区后，沿着管式反应器中进一步反应，得到气相二异氰酸酯混合物，其中管式反应器中反应压力为3bar。然后到骤冷区使用氯苯在130℃温度下对粗二异氰酸酯混合物循环吸收，得到液相粗产品。再经过精馏塔中除去轻/重组分，得到二异氰酸酯产品。气体进入尾气处理装置。
在该实施例中，通过精馏塔得到IPDI产品含量99.6％，色度≤21HAZEN(Apha)(远低于市售产品)，IPDA转化率为99.1％。经过开车运行2个 月之后，停车检修，光气、二胺进料管出口及管式反应器内壁均未见明显结焦物，设备状态良好，不影响反应的继续运转。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对本发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。

Claims (9)

  1. 一种制备二异氰酸酯的方法，其特征包括：
    第一段反应器中进行急速反应移热段：
    a)将光气和二胺进料分别进行加热气化，保证进料喷嘴中反应进料温度为200～300℃；
    b)将布气设备中惰性介质进行加热，保证惰性介质在壳体顶部折射温度为150～250℃；
    c)光气和二胺经过喷嘴分布后，在撞击区进行有效微观混合，惰性介质从上穿过撞击反应区，带走多余热量，气相混合物经过撞击混合反应区后，沿着管式反应器中进一步反应，反应体系进入第二段慢速反应保温段反应；
    第二段反应器中进行慢速反应保温段：
    d)慢速保温段反应得到气相二异氰酸酯混合物；然后到骤冷区通过溶剂对粗二异氰酸酯混合物循环吸收，得到液相粗产品；再经过精馏塔中除去轻/重组分，得到二异氰酸酯产品，气体进入尾气回收装置，吸收并循环。
  2. 根据权利要求1所述的方法，其特征在于：布气设备中惰性介质是氮气、氩气、氦气、氡气、二氧化碳、一氧化碳中一种或多种的混合物。
  3. 根据权利要求1所述的方法，其特征在于：胺与光气进料摩尔比为1:1.2～5，优选1：1.3～4，更优选1：1.5～3，更优选1:1.6～2，更优选1:1.8～2。
  4. 根据权利要求1所述的方法，其特征在于：二胺选自甲苯二胺、亚甲基二苯胺、1,6-己二胺、异佛尔酮二胺、环己烷二胺、1,4-丁二胺、1,5-二氨基-2-甲基戊烷、1,4-二氨基环己烷，间苯二亚甲基二胺，4,4’-二氨基二环己基甲烷、二氨基苯、萘二胺。
  5. 一种用于制备二异氰酸酯的低温气相反应器，其特征包括：
    低温气相反应器包括上下两段，上段为急速反应移热段，下段为慢速反应保温段，两段反应器类型均为夹套管式反应器，且具有各自独立的夹套装置，独立控温；上段急速反应移热段(3)，包括管式壳体(6)及外部分段式夹套(7)、位于所述壳体顶部的布气装置(1)，所述壳体上设置有至少一组均匀、水平分布的进料喷嘴；每组进料喷嘴包括至少一个光气进料喷嘴(21)和至少一个二胺进料喷嘴(22)，反应物料通过喷嘴喷出后在中部撞击区相互撞击，撞击区下部设置圆盘(10)，圆盘直径小于管式反应器内径，其作用为阻止混合物直接进入反应段，使反应混 合物形成乱流，调节光气与胺的接触时间，圆盘(10)连接转轴(4)，使混合气沿器壁下行；在旋转轴上设置扇叶叶片(5)，转动时扇叶将反应物迅速导流至下段；所述布气装置(1)位于所述壳体顶部，进料喷嘴上部，布气装置上表面具有出气装置，惰性介质通过布气设备均匀分布后在壳体顶部折射至撞击反应区，降低反应区温度及浓度；管式壳体外部分段式夹套中存在移热介质，有效控制壳体壁面温度；下段慢速反应保温段，与上段反应器类型相同，但是不设置布气装置和进料喷嘴，且转轴逆向旋转；上段、下段反应器之间通过止回阀(8)和(9)连接；下段反应器出口连接骤冷区，精馏塔和尾气处理装置；光气和二胺进料进入壳体内部采用喷嘴形式进行分散，分散相在两进料管中间撞击，撞击流产生的湍动撞击区位于两进料管之间的稳态区域内，撞击反应区的直径d1＝(0.2～0.6)D，圆盘(10)直径d2＝(0.6～0.9)D，且D为0.5～1米，其中D为管式壳体的内径；圆盘距离喷嘴形成的撞击区平面10～100mm；布气装置选自槽盘式、管式、升气帽式、叶片式中的一种；布气装置和管式壳体顶部的间距为10～100mm，布气装置和稳态撞击区的间距为10～200mm；式壳体外部分段式夹套中存在导热介质，上下段的夹套内的导热介质独立选自导热油、蒸汽、熔盐中的一种；上段急速反应移热段距离500～2000mm；下段慢速反应保温段距离1000～7000mm。
  6. 根据权利要求5所述的反应器，其特征在于：管式壳体上设置有1～4个光气和1～4个二胺进料喷嘴，优选2～3个光气和2～3个二胺进料喷嘴，其中光气进料喷嘴与二胺进料喷嘴交替间隔且均匀、对称、水平分布在反应器壳体，优选光气与二胺进料喷嘴数量相同，优选数量均为2。
  7. 一种使用权利要求5所述反应器制备二异氰酸酯的方法，其特征在于，根据权利要求1至4任一项所述方法采用权利要求5所述反应器制备二异氰酸酯。
  8. 根据权利要求7所述的方法，其特征在于，光气和二胺进料喷嘴中光气和二胺进入撞击区的速度相同且均为10～50米/秒；光气和二胺在撞击区内平均停留时间为0.01～0.5秒；惰性介质通过布气设备均匀分布后在壳体顶部折射至撞击反应区的速度为0.1～8米/秒，上、下段管式反应器中反应压力为0.2～10bar。
  9. 根据权利要求7所述的方法，其特征在于，骤冷区为洗涤塔，骤冷溶剂选自氯苯、二氯苯或异氰酸酯中的一种；骤冷温度100～200℃。
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CN115155467B (zh) * 2022-08-09 2023-10-10 宁夏瑞泰科技股份有限公司 采用液相光气化合成六亚甲基二异氰酸酯的系统及方法

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