CN117886664A - Method for preparing bromobenzene from poly-substituted bromobenzene mixture - Google Patents

Method for preparing bromobenzene from poly-substituted bromobenzene mixture Download PDF

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CN117886664A
CN117886664A CN202410275381.8A CN202410275381A CN117886664A CN 117886664 A CN117886664 A CN 117886664A CN 202410275381 A CN202410275381 A CN 202410275381A CN 117886664 A CN117886664 A CN 117886664A
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bromobenzene
reaction
benzene
stirring
polybrominated
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赵守俊
李荣彬
刘万林
张�杰
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Shouguang Chengxin Salt Industry Co ltd
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Shouguang Chengxin Salt Industry Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
    • C07C17/10—Preparation of halogenated hydrocarbons by replacement by halogens of hydrogen atoms
    • C07C17/12—Preparation of halogenated hydrocarbons by replacement by halogens of hydrogen atoms in the ring of aromatic compounds
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
    • B01J31/1691—Coordination polymers, e.g. metal-organic frameworks [MOF]
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
    • B01J31/22—Organic complexes
    • B01J31/2204—Organic complexes the ligands containing oxygen or sulfur as complexing atoms
    • B01J31/2208—Oxygen, e.g. acetylacetonates
    • B01J31/2226—Anionic ligands, i.e. the overall ligand carries at least one formal negative charge
    • B01J31/223—At least two oxygen atoms present in one at least bidentate or bridging ligand
    • B01J31/2239—Bridging ligands, e.g. OAc in Cr2(OAc)4, Pt4(OAc)8 or dicarboxylate ligands
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/30—Complexes comprising metals of Group III (IIIA or IIIB) as the central metal
    • B01J2531/31—Aluminium
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/30—Complexes comprising metals of Group III (IIIA or IIIB) as the central metal
    • B01J2531/38—Lanthanides other than lanthanum
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/40—Complexes comprising metals of Group IV (IVA or IVB) as the central metal
    • B01J2531/46—Titanium

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  • Inorganic Chemistry (AREA)
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Abstract

The invention provides a method for preparing bromobenzene from a poly-bromobenzene mixture, belonging to the field of bromobenzene preparation. The method for preparing bromobenzene from the polybrominated benzene mixture comprises the following steps: primary reaction, secondary reaction and post-treatment. Aiming at the polybrominated benzene mixture with higher content of tribromobenzene or tetrabromobenzene or pentabromobenzene, the method for preparing bromobenzene from polybrominated benzene has good reaction stability, easy control and controllability of the reaction, and thorough reaction of tribromobenzene, tetrabromobenzene, pentabromobenzene and other components in the polybrominated benzene with benzene under the condition of large-scale industrial production, and can be completely and effectively converted into bromobenzene; the side reaction caused by the catalyst in the reaction process can be effectively inhibited, and the yield and purity of the target product bromobenzene can be synchronously improved; and further improves the separability of the catalyst employed.

Description

Method for preparing bromobenzene from poly-substituted bromobenzene mixture
Technical Field
The invention relates to the field of bromobenzene preparation, in particular to a method for preparing bromobenzene from a poly-bromobenzene mixture.
Background
Bromobenzene is an organic compound, also known as monobromobenzene, of the formula C 6 H 5 Br has the appearance of a colorless oily liquid and has a benzene smell. Bromobenzene is insoluble in water but soluble in methanol and diethyl etherMost organic solvents such as acetone. Bromobenzene density of 1.5+ -0.1 g/cm 3 The boiling point was 154.22 ℃. The refractive index of bromobenzene was 1.556, the critical temperature was 397℃and the critical pressure was 4.52MPa.
Bromobenzene has been widely used in many fields in the prior art. In the aspect of fine chemical engineering, bromobenzene can be used as a raw material of pressure-sensitive and heat-sensitive dyes and a raw material of diphenyl ether series fragrances. In the aspect of pesticide production, bromobenzene can be used as a pesticide raw material, such as bromoxynil for producing pesticide. In the aspect of medicine production, bromobenzene can be used as a starting material of drug molecules, such as the production of analgesic antipyretics and antitussives. In addition, bromobenzene is a common coupling molecule in transition metal catalytic reactions in organic synthesis, and can be subjected to coupling reaction with various compounds to generate corresponding arylate products.
The existing bromobenzene preparation method is mainly a bromine bromination method. Specifically, benzene is used as a raw material, bromine is dropwise added for reaction under the catalysis of iron powder or ferric trichloride, bromobenzene and hydrogen bromide are prepared by the reaction, then the bromobenzene is subjected to refining treatment, and tail gas absorption and other treatments are carried out on the hydrogen bromide. However, in the index process, a certain amount of polybrominated benzene (such as dibromobenzene, tribromobenzene, tetrabromobenzene, pentabromobenzene and the like) is generally produced as a byproduct; in the refining process of bromobenzene preparation, the byproduct polybrominated benzene mixture is generally accumulated in the rectification recombinant.
Although the prior art discloses a method for collecting a byproduct polybrominated benzene mixture in the preparation of bromobenzene and preparing bromobenzene by taking the polybrominated benzene mixture as a raw material, the method aims at polybrominated benzene mixture with high content of tribromobenzene or tetrabromobenzene or pentabromobenzene, and under the condition of large-scale industrial production, the polybrominated benzene has the defects of unsatisfactory reaction stability and poor reaction controllability in the preparation of bromobenzene, and components such as tribromobenzene, tetrabromobenzene, pentabromobenzene and the like react with benzene incompletely in the reaction process, so that the polybrominated benzene cannot be completely and effectively converted into bromobenzene; meanwhile, in the reaction process, the adopted catalyst can also generate side reactions such as electrophilic substitution on aromatic rings and the like with polybrominated benzene and benzene, and further, byproducts (such as halogenated benzene and the like) are generated. In order to enable the dibromobenzene, the tribromobenzene and the like which are regenerated in the reaction process to continuously participate in the reaction to generate bromobenzene, the conventional means of prolonging the reaction time, improving the reaction pressure, increasing the raw material benzene consumption, increasing the catalyst consumption and the like can further aggravate the progress of side reactions in the reaction process, and finally, the dibromobenzene, the tribromobenzene and the like which are regenerated in the reaction cannot continuously and effectively react in the reaction process of preparing bromobenzene by the multi-substituted bromobenzene, so that new byproducts are continuously accumulated, the new byproducts cannot be thoroughly converted into bromobenzene which is a target product, the yield of bromobenzene which is the target product is to be further improved, and better reaction effect and bromobenzene purity index cannot be obtained on the premise of ideal bromobenzene yield.
Furthermore, in the existing method for preparing bromobenzene by using polybrominated benzene on the basis of the defects, the adopted Lewis acid catalyst is not easy to separate from the reaction system, for example, the boiling points of adopted aluminum trichloride, stannic chloride, titanium tetrachloride and the like are all close to that of the bromobenzene which is a target product, and separation can not be carried out only through distillation treatment, so that the subsequent difficulty in separating and purifying the reaction mixed product and the production energy consumption can be further increased; and the production amount of hazardous waste in the post-treatment process is large, and the environmental friendliness is poor.
Disclosure of Invention
Aiming at the polybrominated benzene mixture with higher content of tribromobenzene or tetrabromobenzene or pentabromobenzene, the invention provides a method for preparing bromobenzene from polybrominated benzene mixture, which aims at solving the technical problems existing in the prior art, has good reaction stability of polybrominated benzene for preparing bromobenzene under the condition of large-scale industrial production, is easy to control and controllable in reaction, and components such as tribromobenzene, tetrabromobenzene, pentabromobenzene and the like in the polybrominated benzene are thoroughly reacted with benzene, so that the polybrominated benzene can be completely and effectively converted into bromobenzene; the side reaction caused by the catalyst in the reaction process can be effectively inhibited, and the yield and purity of the target product bromobenzene can be synchronously improved; and further improves the separability of the catalyst employed.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for preparing bromobenzene from a polybrominated benzene mixture, which comprises the following steps: primary reaction, secondary reaction and post-treatment.
Pumping benzene into a high-level metering tank, metering the benzene, flowing the benzene into a reaction kettle under the action of gravity, stirring and heating to 40-50 ℃, and preserving heat; then adding the polybrominated benzene into a reaction kettle, completely replacing air in the reaction kettle by adopting nitrogen, and regulating the pressure in the reaction kettle to be 0.05-0.08MPa; heating to 90-95 ℃ at a heating rate of 0.5-1 ℃/min, and carrying out heat preservation and stirring reaction for 2-3h to complete the primary reaction, thus obtaining the primary reactant.
In the primary reaction, a condenser is arranged at the upper end of the reaction kettle, and gas phase light components in the primary reaction process are condensed by the condenser and then fully reflux into the reaction kettle to continue the reaction.
In the primary reaction, the sum of the weight percentages of tribromobenzene, tetrabromobenzene, pentabromobenzene and hexabromobenzene in the polybrominated benzene is more than 75%.
Preferably, in the primary reaction, the molar ratio of the polybrominated benzene to the benzene is 1:2.8-3.
The catalyst is fixedly filled in the reaction kettle, and the filling amount of the catalyst is 2.5-3.5% of the weight of the polybrominated benzene.
The catalyst is prepared by the following steps: compounding, primary treatment and secondary treatment.
Putting titanium tetrachloride, aluminum trichloride, neodymium trichloride and hollow mesoporous silica microspheres into N, N-dimethylformamide DMF, carrying out ultrasonic dispersion uniformly, then continuously putting phthalic acid, carrying out ultrasonic dispersion uniformly, transferring into a high-pressure reaction kettle, sealing the high-pressure reaction kettle, controlling the temperature of materials in the high-pressure reaction kettle to be 120-130 ℃, carrying out heat preservation, stirring for reaction for 10-12 hours, naturally cooling to room temperature, taking out the materials in the high-pressure reaction kettle, separating to obtain solid matters, washing the solid matters for 2-3 times by adopting deionized water with the volume of 7-8 times, transferring into a vacuum drying box, and drying at the temperature of 80-90 ℃ for 6-9 hours under the condition of the vacuum degree of 0.07-0.09MPa to obtain the compound.
Preferably, in the compounding, the weight ratio of titanium tetrachloride to aluminum trichloride to neodymium trichloride to hollow mesoporous silica microspheres to phthalic acid to N, N-dimethylformamide DMF is 20-22:13-15:7-8:25-30:35-38:1000-1200;
the particle size of the hollow mesoporous silica microsphere is 100-120nm.
The primary treatment method comprises the steps of adopting sodium hydroxide solution to adjust the pH value of ethanol solution with the volume concentration of 40-50% to 7.5-8, then adding the compound, stirring uniformly, heating to 40-45 ℃, and preserving heat; under the stirring condition, simultaneously dripping the silane coupling agent A-151 and the silane coupling agent A-172, continuously preserving heat and stirring for 5-6 hours after the dripping is completed, separating out solid matters, washing the solid matters by deionized water with the volume of 4-5 times, transferring the solid matters into a vacuum drying oven, and drying for 8-10 hours at the temperature of 75-85 ℃ under the condition of the vacuum degree of 0.08-0.09MPa to obtain the primary treated matters.
Preferably, in the one-time treatment, the weight ratio of the compound to the ethanol solution to the silane coupling agent A-151 to the silane coupling agent A-172 is 25-30:300-320:3-3.5:1-1.2;
the concentration of the sodium hydroxide solution is 0.1-0.2mol/L.
The secondary treatment method comprises the steps of adding polysorbate-80 into N-heptane, dispersing uniformly, adding methacrylamide, vinylglycine and N, N' -methylene bisacrylamide continuously, stirring for 1-2h, adding the primary treated matter continuously, dispersing uniformly, transferring into a reaction kettle, adding azodiisobutyronitrile in a nitrogen atmosphere environment, stirring and heating to 55-65 ℃, preserving heat and stirring for 5-6h, separating out solid matters, washing the solid matters by absolute ethyl alcohol with the volume of 4-5 times, transferring into a vacuum drying box, and drying for 10-12h at 70-80 ℃ under the condition of 0.05-0.06MPa to obtain the catalyst.
Preferably, in the secondary treatment, the weight ratio of polysorbate-80, N-heptane, methacrylamide, vinylglycine, N' -methylenebisacrylamide, primary treatment substance and azodiisobutyronitrile is 1.2-1.5:120-130:0.55-0.65:1.6-1.8:2-2.5:10-12:0.25-0.3.
The secondary reaction method is that after the primary reaction is completed, stirring and heating are continued to 100-105 ℃, and heat preservation is carried out; then dropwise adding benzene into the reaction kettle at a dropwise speed of 20-25mL/min under the stirring condition; meanwhile, an online chromatograph is adopted to monitor the mass percentage content of the p-dibromobenzene, the o-dibromobenzene and the m-dibromobenzene in the materials in the reaction kettle in real time, when the weight percentage content of the dibromobenzene, the o-dibromobenzene and the m-dibromobenzene is lower than 0.1 percent and the weight percentage content of the dibromobenzene, the o-dibromobenzene and the m-dibromobenzene in the following 10-20min is not more than +/-0.02 percent, the dripping of benzene is stopped, the heat preservation and stirring are continued for 20-40min, and the secondary reaction is completed, thus obtaining the secondary reactant.
And condensing the gas phase light components in the secondary reaction process through a condenser, and then fully refluxing the gas phase light components into the reaction kettle to continue the reaction.
Filtering out solid matters in the secondary reactant, introducing the solid matters into an atmospheric distillation device, heating to 138-140 ℃, and distilling at a temperature to remove unreacted benzene and light component impurities; continuously heating to 155-157 ℃, preserving heat and distilling, controlling the reflux ratio to be 1:2.5-3, condensing and collecting light components to obtain bromobenzene, wherein the liquid chromatographic purity is 99.68-99.74wt% and the yield is 96.0-96.5%.
In the post-treatment process, solid matters in the secondary reactant in the filtering process and distilled heavy components are respectively collected and combined, and then the heavy components are combined with the byproduct poly-bromobenzene in the production of bromobenzene in other batches, and then primary reaction, secondary reaction and post-treatment are carried out again to prepare bromobenzene.
Compared with the prior art, the invention has the beneficial effects that:
(1) According to the method for preparing bromobenzene from the polybrominated benzene mixture, a part of benzene and polybrominated benzene are subjected to primary reaction under the catalysis of a catalyst, and then a primary reactant is obtained; then, dripping benzene into the first-stage reactant for reaction, and carrying out secondary reaction until the weight percentage of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene in the reaction materials is lower than 0.1%, and stopping dripping benzene to obtain a second-stage reactant; the secondary reactant is post-treated to prepare bromobenzene; meanwhile, in the compounding step of the catalyst, a metal organic framework material is prepared by adopting metal active components with synergistic catalytic performance and is compounded with hollow mesoporous silica microspheres to obtain a compound with catalytic activity; then in the primary treatment step, the specific vinyl silane coupling agent is matched to carry out modification treatment on the compound, so that the combination property of the compound in the subsequent treatment is improved; then combining double bond-containing methacrylamide and vinyl glycine containing vinyl with the primary treatment substance to prepare a catalyst with stable catalytic performance; aiming at a polybrominated benzene mixture with higher content of tribromobenzene or tetrabromobenzene or pentabromobenzene, under the condition of large-scale industrial production, the polybrominated benzene has good reaction stability for preparing bromobenzene, the reaction is easy to control and controllable, and the components such as tribromobenzene, tetrabromobenzene, pentabromobenzene and the like in the polybrominated benzene are thoroughly reacted with benzene and can be completely and effectively converted into bromobenzene; the side reaction caused by the catalyst in the reaction process can be effectively inhibited, and the yield and purity of the target product bromobenzene can be synchronously improved; and further improves the separability of the catalyst employed.
(2) The method for preparing bromobenzene from the polybrominated benzene mixture adopts polybrominated benzene mixture (the sum of the weight percentages of tribromobenzene, tetrabromobenzene, pentabromobenzene and hexabromobenzene in the mixture is more than 75%) which is generated by byproducts in the bromobenzene preparation process as a raw material, and the polybrominated benzene mixture reacts with benzene under the catalysis of a catalyst to prepare bromobenzene, wherein the liquid chromatographic purity of the bromobenzene is 99.68-99.74wt% and the yield is 96.0-96.5%; the stable production of bromobenzene prepared from the multi-substituted bromobenzene is effectively realized under the condition of large-scale industrial production, the byproduct (multi-substituted bromobenzene) generated in the bromobenzene preparation process is effectively recycled, the utilization rate of the production raw materials is effectively improved, the production resources are saved, and the production cost is reduced.
(3) In the method for preparing bromobenzene by using the polybrominated benzene mixture, the adopted catalyst has good long-term catalytic performance, after 15 times of bromobenzene preparation are repeatedly carried out, the liquid chromatographic purity of the prepared bromobenzene can still reach 99.41-99.50wt%, the yield can still reach 94.0-94.9%, the catalytic performance of the catalyst has small decay, the better catalytic performance can be kept for a long time, and the repeated utilization of the catalyst can be realized.
(4) In the method for preparing bromobenzene from the polybrominated benzene mixture, the adopted catalyst has good long-term storage stability, the temperature is 40 ℃, the relative humidity is 60 percent, and the yield in preparing bromobenzene from the polybrominated benzene mixture can still reach 96.1 percent after standing and storing for 4 months; meanwhile, after standing and storing for 4 months, the optimal catalytic temperature of the catalyst is 92.5 ℃, the catalyst can still adapt to the reaction temperature range of 92-95 ℃ in the primary reaction, and the catalytic performance of the stored catalyst is not obviously different from that of a new catalyst.
(5) According to the method for preparing bromobenzene from the polybrominated benzene mixture, in the filtering and distilling processes of post-treatment, solid matters and distilled heavy components obtained by filtering can be combined with the polybrominated benzene mixture and then reused in preparation of bromobenzene, so that the utilization rate of production raw materials is further improved, and waste of the production raw materials is avoided.
(6) The method for preparing bromobenzene from the polybrominated benzene mixture has simple process, is easy to control and is suitable for large-scale industrial production.
Detailed Description
Specific embodiments of the present invention will now be described in order to provide a clearer understanding of the technical features, objects and effects of the present invention.
Example 1
A method for preparing bromobenzene from a polybrominated benzene mixture comprises the following specific scheme:
in the embodiment, the sum of the weight percentages of tribromobenzene, tetrabromobenzene, pentabromobenzene and hexabromobenzene in the adopted polybromobenzene is more than 75 percent; specifically, the weight percentage of dibromobenzene in the poly-bromobenzene is 21.3%, the weight percentage of tribromobenzene is 51.4%, the weight percentage of tetrabromobenzene is 23.6%, and the weight percentage of pentabromobenzene is 3.7%.
1. First-order reaction
Pumping benzene into a high-level metering tank, metering the benzene, flowing the benzene into a reaction kettle under the action of gravity, stirring and heating to 40 ℃, and preserving heat; then adding the polybrominated benzene into a reaction kettle, completely replacing air in the reaction kettle by adopting nitrogen, and regulating the pressure in the reaction kettle to be 0.05MPa; heating to 90 ℃ at a heating rate of 0.5 ℃/min, and carrying out heat preservation and stirring reaction for 2 hours to complete the primary reaction, thus obtaining the primary reactant.
Meanwhile, the upper end of the reaction kettle is provided with a condenser, and gas phase light components in the primary reaction process are condensed by the condenser and then fully reflux into the reaction kettle to continue the reaction.
In the primary reaction, the molar ratio of the polybrominated benzene to the benzene is 1:2.8.
The catalyst is fixedly filled in the reaction kettle, and the filling amount of the catalyst is 2.5 percent of the weight of the polybrominated benzene.
The catalyst is prepared by the following steps:
1) Composite material
Putting titanium tetrachloride, aluminum trichloride, neodymium trichloride and hollow mesoporous silica microspheres into N, N-dimethylformamide DMF, continuously putting phthalic acid after ultrasonic dispersion is uniform, transferring into a high-pressure reaction kettle, sealing the high-pressure reaction kettle, controlling the temperature of materials in the high-pressure reaction kettle to be 120 ℃, preserving heat, stirring for reaction for 10 hours, naturally cooling to room temperature, taking out the materials in the high-pressure reaction kettle, separating to obtain solid matters, washing the solid matters with deionized water with 7 times of volume for 2 times, transferring into a vacuum drying box, and drying at 80 ℃ for 6 hours under the condition of 0.07MPa of vacuum degree to obtain the compound.
Wherein the weight ratio of titanium tetrachloride, aluminum trichloride, neodymium trichloride to hollow mesoporous silica microsphere to phthalic acid to N, N-dimethylformamide DMF is 20:13:7:25:35:1000.
The particle size of the hollow mesoporous silica microsphere is 100nm.
2) One-time treatment
Adjusting the pH value of an ethanol solution with the volume concentration of 40% to 7.5 by adopting a sodium hydroxide solution, then adding the compound, uniformly stirring, heating to 40 ℃, and preserving heat; and (3) under the stirring condition, simultaneously dripping the silane coupling agent A-151 and the silane coupling agent A-172, continuously preserving heat and stirring for 5 hours after the dripping is completed, separating out solid matters, washing the solid matters by deionized water with the volume of 4 times, transferring the solid matters into a vacuum drying oven, and drying at 75 ℃ for 8 hours under the condition of the vacuum degree of 0.08MPa to obtain the primary treated matters.
Wherein the weight ratio of the compound to the ethanol solution to the silane coupling agent A-151 to the silane coupling agent A-172 is 25:300:3:1.
The concentration of the sodium hydroxide solution was 0.1mol/L.
3) Secondary treatment
Adding polysorbate-80 into N-heptane, dispersing uniformly, adding methacrylamide, vinylglycine and N, N' -methylene bisacrylamide continuously, stirring for 1h, adding the treated matter continuously, dispersing uniformly, transferring into a reaction kettle, adding azodiisobutyronitrile in a nitrogen atmosphere environment, stirring and heating to 55 ℃, preserving heat and stirring for 5h, separating out solid matters, washing the solid matters with 4 times of absolute ethyl alcohol, transferring into a vacuum drying box, and drying at 70 ℃ for 10h under the condition of 0.05MPa to obtain the catalyst.
Wherein, the weight ratio of polysorbate-80, N-heptane, methacrylamide, vinylglycine, N' -methylenebisacrylamide, primary treatment substance and azodiisobutyronitrile is 1.2:120:0.55:1.6:2:10:0.25.
2. Secondary reaction
After the primary reaction is finished, continuing stirring and heating to 100 ℃, and preserving heat; then dropwise adding benzene into the reaction kettle at a dropwise speed of 20mL/min under the stirring condition; meanwhile, monitoring the mass percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene in materials in a reaction kettle in real time by adopting an online chromatograph, stopping dripping benzene when the weight percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene is less than 0.1% and the weight percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene is not more than +/-0.02% in the following 10min, continuing to keep the temperature and stir for 20min, and completing a secondary reaction to obtain a secondary reactant.
Meanwhile, the gas phase light components in the second-stage reaction process are condensed by a condenser and then fully reflux into the reaction kettle to continue the reaction.
3. Post-treatment
Filtering out solid matters in the secondary reactant, introducing the solid matters into an atmospheric distillation device, heating to 138 ℃, and distilling at a constant temperature to remove unreacted benzene and light component impurities; continuously heating to 155 ℃, preserving heat and distilling, controlling the reflux ratio to be 1:2.5, condensing and collecting light components to prepare bromobenzene; the liquid chromatography purity of bromobenzene was 99.68wt% and the yield was 96.0%.
In the post-treatment process, solid matters in the secondary reactant in the filtering process and distilled heavy components are respectively collected and combined, and then the heavy components are combined with the byproduct poly-bromobenzene in the production of bromobenzene in other batches, and then primary reaction, secondary reaction and post-treatment are carried out again to prepare bromobenzene.
Example 2
A method for preparing bromobenzene from a polybrominated benzene mixture comprises the following specific scheme:
in the embodiment, the sum of the weight percentages of tribromobenzene, tetrabromobenzene, pentabromobenzene and hexabromobenzene in the adopted polybromobenzene is more than 75 percent; specifically, the weight percentage of dibromobenzene in the poly-bromobenzene is 21.3%, the weight percentage of tribromobenzene is 51.4%, the weight percentage of tetrabromobenzene is 23.6%, and the weight percentage of pentabromobenzene is 3.7%.
1. First-order reaction
Pumping benzene into a high-level metering tank, metering the benzene, flowing the benzene into a reaction kettle under the action of gravity, stirring and heating to 45 ℃, and preserving heat; then adding the polybrominated benzene into a reaction kettle, completely replacing air in the reaction kettle by adopting nitrogen, and regulating the pressure in the reaction kettle to be 0.07MPa; heating to 92 ℃ at the heating rate of 0.8 ℃/min, and carrying out heat preservation and stirring reaction for 2.5h to complete the primary reaction, thus obtaining the primary reactant.
Meanwhile, the upper end of the reaction kettle is provided with a condenser, and gas phase light components in the primary reaction process are condensed by the condenser and then fully reflux into the reaction kettle to continue the reaction.
In the primary reaction, the molar ratio of the polybrominated benzene to the benzene is 1:2.9.
The catalyst is fixedly filled in the reaction kettle, and the filling amount of the catalyst is 3.2 percent of the weight of the polybrominated benzene.
The catalyst is prepared by the following steps:
1) Composite material
Putting titanium tetrachloride, aluminum trichloride, neodymium trichloride and hollow mesoporous silica microspheres into N, N-dimethylformamide DMF, continuously putting phthalic acid after ultrasonic dispersion is uniform, transferring into a high-pressure reaction kettle, sealing the high-pressure reaction kettle, controlling the temperature of materials in the high-pressure reaction kettle to be 125 ℃, preserving heat, stirring for 11h, naturally cooling to room temperature, taking out materials in the high-pressure reaction kettle, separating to obtain solid matters, washing the solid matters 3 times by adopting deionized water with the volume of 7.5 times, transferring into a vacuum drying box, and drying at the temperature of 85 ℃ for 8h under the condition of the vacuum degree of 0.08MPa to obtain the compound.
Wherein the weight ratio of titanium tetrachloride to aluminum trichloride to neodymium trichloride to hollow mesoporous silica microsphere to phthalic acid to N, N-dimethylformamide DMF is 21:14:7.5:27:36:1100.
The particle size of the hollow mesoporous silica microsphere is 110nm.
2) One-time treatment
Regulating the pH value of an ethanol solution with the volume concentration of 45% to 7.8 by adopting a sodium hydroxide solution, then adding the compound, uniformly stirring, heating to 42 ℃, and preserving heat; under the stirring condition, simultaneously dripping the silane coupling agent A-151 and the silane coupling agent A-172, continuously preserving heat and stirring for 5.5 hours after the dripping is completed, separating out solid matters, washing the solid matters by deionized water with the volume of 4.5 times, transferring the solid matters into a vacuum drying oven, and drying for 9 hours at 80 ℃ under the condition of the vacuum degree of 0.085MPa to obtain the primary treated matters.
Wherein the weight ratio of the compound to the ethanol solution to the silane coupling agent A-151 to the silane coupling agent A-172 is 28:310:3.2:1.1.
The concentration of the sodium hydroxide solution was 0.15mol/L.
3) Secondary treatment
Adding polysorbate-80 into N-heptane, dispersing uniformly, adding methacrylamide, vinylglycine and N, N' -methylene bisacrylamide continuously, stirring for 1.5 hours, adding the treated substances continuously, dispersing uniformly, transferring into a reaction kettle, adding azodiisobutyronitrile in a nitrogen atmosphere environment, stirring and heating to 60 ℃, preserving heat and stirring for 5.5 hours, separating out solid matters, washing the solid matters by 4.5 times of absolute ethyl alcohol, transferring into a vacuum drying box, and drying at 75 ℃ for 11 hours under the condition of 0.055MPa to obtain the catalyst.
Wherein, the weight ratio of polysorbate-80, N-heptane, methacrylamide, vinylglycine, N' -methylenebisacrylamide, primary treatment substance and azodiisobutyronitrile is 1.3:125:0.6:1.7:2.3:11:0.28.
2. Secondary reaction
After the primary reaction is finished, continuing stirring and heating to 102 ℃, and preserving heat; then dropwise adding benzene into the reaction kettle at a dropwise speed of 23mL/min under the stirring condition; meanwhile, monitoring the mass percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene in materials in a reaction kettle in real time by adopting an online chromatograph, stopping dripping benzene when the weight percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene is less than 0.1% and the weight percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene is not more than +/-0.02% in the subsequent 15min, continuing to keep the temperature and stir for 30min, and completing a secondary reaction to obtain a secondary reactant.
Meanwhile, the gas phase light components in the second-stage reaction process are condensed by a condenser and then fully reflux into the reaction kettle to continue the reaction.
3. Post-treatment
Filtering out solid matters in the secondary reactant, introducing the solid matters into an atmospheric distillation device, heating to 139 ℃, and distilling at a temperature of between 139 ℃ to remove unreacted benzene and light component impurities; continuously heating to 156 ℃, preserving heat and distilling, controlling the reflux ratio to be 1:2.8, condensing and collecting light components to prepare bromobenzene; the liquid chromatographic purity of bromobenzene was 99.74wt% and the yield was 96.5%.
In the post-treatment process, solid matters in the secondary reactant in the filtering process and distilled heavy components are respectively collected and combined, and then the heavy components are combined with the byproduct poly-bromobenzene in the production of bromobenzene in other batches, and then primary reaction, secondary reaction and post-treatment are carried out again to prepare bromobenzene.
Example 3
A method for preparing bromobenzene from a polybrominated benzene mixture comprises the following specific scheme:
in the embodiment, the sum of the weight percentages of tribromobenzene, tetrabromobenzene, pentabromobenzene and hexabromobenzene in the polybrominated benzene is more than 75%; specifically, the weight percentage of dibromobenzene in the poly-bromobenzene is 21.3%, the weight percentage of tribromobenzene is 51.4%, the weight percentage of tetrabromobenzene is 23.6%, and the weight percentage of pentabromobenzene is 3.7%.
1. First-order reaction
Pumping benzene into a high-level metering tank, metering the benzene, flowing the benzene into a reaction kettle under the action of gravity, stirring and heating to 50 ℃, and preserving heat; then adding the polybrominated benzene into a reaction kettle, completely replacing air in the reaction kettle by adopting nitrogen, and regulating the pressure in the reaction kettle to be 0.08MPa; heating to 95 ℃ at a heating rate of 1 ℃/min, and carrying out heat preservation and stirring reaction for 3 hours to complete the primary reaction, thereby obtaining the primary reactant.
Meanwhile, the upper end of the reaction kettle is provided with a condenser, and gas phase light components in the primary reaction process are condensed by the condenser and then fully reflux into the reaction kettle to continue the reaction.
In the primary reaction, the molar ratio of the polybrominated benzene to the benzene is 1:3.
The catalyst is fixedly filled in the reaction kettle, and the filling amount of the catalyst is 3.5 percent of the weight of the polybrominated benzene.
The catalyst is prepared by the following steps:
1) Composite material
Putting titanium tetrachloride, aluminum trichloride, neodymium trichloride and hollow mesoporous silica microspheres into N, N-dimethylformamide DMF, continuously putting phthalic acid after ultrasonic dispersion is uniform, transferring into a high-pressure reaction kettle, sealing the high-pressure reaction kettle, controlling the temperature of materials in the high-pressure reaction kettle to be 130 ℃, preserving heat, stirring for reaction for 12 hours, naturally cooling to room temperature, taking out materials in the high-pressure reaction kettle, separating to obtain solid matters, washing the solid matters 3 times by adopting deionized water with the volume of 8 times, transferring into a vacuum drying oven, and drying at 90 ℃ for 9 hours under the condition of the vacuum degree of 0.09MPa to obtain the compound.
Wherein the weight ratio of titanium tetrachloride to aluminum trichloride to neodymium trichloride to hollow mesoporous silica microsphere to phthalic acid to N, N-dimethylformamide DMF is 22:15:8:30:38:1200.
The particle size of the hollow mesoporous silica microsphere is 120nm.
2) One-time treatment
Adjusting the pH value of an ethanol solution with the volume concentration of 50% to 8 by adopting a sodium hydroxide solution, then adding the compound, uniformly stirring, heating to 45 ℃, and preserving heat; and (3) under the stirring condition, simultaneously dripping the silane coupling agent A-151 and the silane coupling agent A-172, continuously preserving heat and stirring for 6 hours after the dripping is completed, separating out solid matters, washing the solid matters by 5 times of deionized water, transferring the solid matters into a vacuum drying oven, and drying at 85 ℃ for 10 hours under the condition of 0.09MPa of vacuum degree to obtain the primary treated matters.
Wherein the weight ratio of the compound to the ethanol solution to the silane coupling agent A-151 to the silane coupling agent A-172 is 30:320:3.5:1.2.
The concentration of the sodium hydroxide solution was 0.2mol/L.
3) Secondary treatment
Adding polysorbate-80 into N-heptane, dispersing uniformly, adding methacrylamide, vinylglycine and N, N' -methylene bisacrylamide continuously, stirring for 2 hours, adding the treated matter continuously, dispersing uniformly, transferring into a reaction kettle, adding azodiisobutyronitrile in a nitrogen atmosphere environment, stirring and heating to 65 ℃, preserving heat and stirring for 6 hours, separating out solid matters, washing the solid matters by 5 times of absolute ethyl alcohol, transferring into a vacuum drying box, and drying at 80 ℃ for 12 hours under the condition of 0.06MPa to obtain the catalyst.
Wherein, the weight ratio of polysorbate-80, N-heptane, methacrylamide, vinylglycine, N' -methylenebisacrylamide, primary treatment substance and azodiisobutyronitrile is 1.5:130:0.65:1.8:2.5:12:0.3.
2. Secondary reaction
After the primary reaction is finished, continuing stirring and heating to 105 ℃, and preserving heat; then dropwise adding benzene into the reaction kettle at a dropwise speed of 25mL/min under the stirring condition; meanwhile, monitoring the mass percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene in materials in a reaction kettle in real time by adopting an online chromatograph, stopping dripping benzene when the weight percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene is less than 0.1% and the weight percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene is not more than +/-0.02% in the subsequent 20min, continuing to keep the temperature and stir for 40min, and completing a secondary reaction to obtain a secondary reactant.
Meanwhile, the gas phase light components in the second-stage reaction process are condensed by a condenser and then fully reflux into the reaction kettle to continue the reaction.
3. Post-treatment
Filtering out solid matters in the secondary reactant, introducing the solid matters into an atmospheric distillation device, heating to 140 ℃, and distilling at a temperature of heat preservation to remove unreacted benzene and light component impurities; continuously heating to 157 ℃, preserving heat and distilling, controlling the reflux ratio to be 1:3, condensing and collecting light components to prepare bromobenzene; the liquid chromatography purity of bromobenzene was 99.71wt% and the yield was 96.2%.
In the post-treatment process, solid matters in the secondary reactant in the filtering process and distilled heavy components are respectively collected and combined, and then the heavy components are combined with the byproduct poly-bromobenzene in the production of bromobenzene in other batches, and then primary reaction, secondary reaction and post-treatment are carried out again to prepare bromobenzene.
Comparative example 1
The technical scheme of the embodiment 2 is adopted, and the difference is that: 1) Omitting a secondary reaction step, directly adding all doses of benzene and polybrominated benzene into a reaction kettle, carrying out heat preservation reaction for 8 hours at 92 ℃, and directly carrying out a post-treatment step; wherein the molar ratio of the polybrominated benzene to the benzene is 1:5. 2) The primary treatment step in the preparation of the catalyst is omitted.
In the technical scheme of comparative example 1, the problems of long reaction time and large benzene excess exist in the bromobenzene preparation process, and longer debenzolization time and energy consumption are required in the post-treatment process, so that the production efficiency is low and the production cost is high. The bromobenzene obtained in comparative example 1 was found to have a liquid chromatography purity of 97.96wt% and a yield of 93.3%. It can be seen that the secondary reaction step and the primary treatment step are omitted, and the influence on the mass production of bromobenzene prepared by using the multi-substituted bromobenzene mixture is larger; meanwhile, according to analysis, the reason that the bromobenzene yield is reduced to a certain extent is mainly that after one treatment step is omitted, a specific vinyl silane coupling agent is not adopted to be matched for modifying the compound, so that the combination property of the compound and subsequent active ingredients is reduced, and the catalytic performance is gradually degraded in the long-time production process.
Comparative example 2
The technical scheme of the embodiment 2 is adopted, and the difference is that: 1) In the compounding step in the preparation of the catalyst, the addition of titanium tetrachloride and neodymium trichloride is omitted. 2) The secondary treatment step in the preparation of the catalyst is omitted.
The liquid chromatographic purity of bromobenzene obtained in comparative example 2 was 95.21wt% and the yield was 85.4%. It can be seen that the catalyst prepared by the steps can not realize multi-component synergistic catalysis in the process of preparing bromobenzene by reacting poly-bromobenzene with benzene, and the catalyst has unsatisfactory catalytic performance and is particularly expressed as the reduction of bromobenzene yield.
Further, after bromobenzene was prepared by repeating the process for 15 times using the catalysts of examples 1 to 3 and comparative examples 1 to 2, respectively, the liquid chromatographic purity and yield of bromobenzene prepared in bromobenzene preparation from the 16 th-time polybrominated benzene mixture were examined, and the specific results are shown in the following table:
further, the catalysts used in example 2 and comparative examples 1 to 2 were placed in an environment with a temperature of 40 ℃ and a relative humidity of 60%, and after standing and storing for 4 months, bromobenzene was prepared by the method for preparing bromobenzene from the multi-substituted bromobenzene mixture of example 2, and the yield of bromobenzene prepared was counted; at the same time, the optimum catalytic temperature of each catalyst is determined separately. The specific results are shown in the following table:
it can be seen that the catalyst adopted in the process of preparing bromobenzene from the polybrominated benzene mixture has stable long-term catalytic performance, and the catalyst has small degradation of catalytic performance after repeated recycling for many times, and can keep good catalytic performance for a long time; meanwhile, the catalyst has good long-term storage stability, and the catalytic performance of the catalyst after long-term storage is not obviously different from that of a new catalyst.
In comparative example 2, the secondary reaction step and the primary treatment step are omitted, and the specific vinyl silane coupling agent is not adopted to match for modifying the compound, so that the combination property of the compound and the subsequent active ingredients is reduced, and finally the long-term catalytic performance and the long-term storage stability of the catalyst are obviously reduced.
According to the method for preparing bromobenzene from the polybrominated benzene mixture, a part of benzene and polybrominated benzene are subjected to primary reaction under the catalysis of a catalyst, and then a primary reactant is obtained; then, dripping benzene into the first-stage reactant for reaction, and carrying out secondary reaction until the weight percentage of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene in the reaction materials is lower than 0.1%, and stopping dripping benzene to obtain a second-stage reactant; the secondary reactant is post-treated to prepare bromobenzene; meanwhile, in the compounding step of the catalyst, a metal organic framework material is prepared by adopting metal active components with synergistic catalytic performance and is compounded with hollow mesoporous silica microspheres to obtain a compound with catalytic activity; then in the primary treatment step, the specific vinyl silane coupling agent is matched to carry out modification treatment on the compound, so that the combination property of the compound in the subsequent treatment is improved; then combining double bond-containing methacrylamide and vinyl glycine containing vinyl with the primary treatment substance to prepare a catalyst with stable catalytic performance; aiming at a polybrominated benzene mixture with higher content of tribromobenzene or tetrabromobenzene or pentabromobenzene, under the condition of large-scale industrial production, the polybrominated benzene has good reaction stability for preparing bromobenzene, the reaction is easy to control and controllable, and the components such as tribromobenzene, tetrabromobenzene, pentabromobenzene and the like in the polybrominated benzene are thoroughly reacted with benzene and can be completely and effectively converted into bromobenzene; the side reaction caused by the catalyst in the reaction process can be effectively inhibited, and the yield and purity of the target product bromobenzene can be synchronously improved; and further improves the separability of the catalyst employed.
The percentages used in the present invention are mass percentages unless otherwise indicated.
Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A method for preparing bromobenzene from a mixture of polybrominated benzenes, comprising the steps of: primary reaction, secondary reaction and post-treatment;
the primary reaction method comprises the steps of putting benzene into a reaction kettle which is fixedly filled with a catalyst, stirring and heating to 40-50 ℃, and preserving heat; then adding polybrominated benzene into a reaction kettle, controlling the reaction pressure to be 0.05-0.08MPa in a nitrogen atmosphere environment, heating to 90-95 ℃, and carrying out heat preservation and stirring reaction for 2-3h to complete primary reaction and obtain a primary reactant;
the sum of the weight percentages of tribromobenzene, tetrabromobenzene, pentabromobenzene and hexabromobenzene in the polybromobenzene is more than 75%;
the catalyst is prepared by the following steps: compounding, primary treatment and secondary treatment;
putting titanium tetrachloride, aluminum trichloride, neodymium trichloride and hollow mesoporous silica microspheres into N, N-dimethylformamide, continuously putting phthalic acid after uniform dispersion, transferring into a high-pressure reaction kettle after uniform dispersion, sealing the high-pressure reaction kettle, heating to 120-130 ℃, preserving heat, stirring for reaction, naturally cooling to room temperature, separating to obtain a solid, washing the solid with deionized water, and vacuum drying to obtain a compound;
the primary treatment method comprises the steps of adopting sodium hydroxide solution to adjust the pH value of ethanol solution to 7.5-8, then adding the compound, stirring uniformly, heating to 40-45 ℃, and preserving heat; under the stirring condition, simultaneously dripping the silane coupling agent A-151 and the silane coupling agent A-172, continuously preserving heat and stirring after the dripping is completed, separating out solid matters, washing the solid matters by deionized water, and carrying out vacuum drying to obtain a primary treated matter;
the secondary treatment method comprises the steps of adding polysorbate-80 into N-heptane, dispersing uniformly, continuing to add methacrylamide, vinylglycine and N, N' -methylene bisacrylamide, stirring uniformly, continuing to add primary treated matters, dispersing uniformly, adding azodiisobutyronitrile in a nitrogen atmosphere environment, stirring and heating to 55-65 ℃, preserving heat and stirring, separating out solid matters, washing the solid matters with absolute ethyl alcohol, and drying in vacuum to obtain the catalyst;
the secondary reaction method is that after the primary reaction is completed, stirring and heating are continued to 100-105 ℃, and heat preservation is carried out; then stirring and dripping benzene; simultaneously monitoring the mass percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene in the materials in the reaction kettle, stopping dripping benzene when the weight percentage content of p-dibromobenzene, o-dibromobenzene and m-dibromobenzene is lower than 0.1% and no obvious change exists in 10-20min, and continuing to keep the temperature and stirring to complete the secondary reaction to obtain a secondary reactant;
the post-treatment method is that the secondary reactant is filtered, distilled to remove impurities, and distilled to obtain bromobenzene.
2. The method for preparing bromobenzene from a polybrominated benzene mixture according to claim 1, characterized in that in the primary reaction, the heating rate to 90-95 ℃ is 0.5-1 ℃/min;
the molar ratio of the polybrominated benzene to the benzene in the primary reaction is 1:2.8-3;
the loading of the catalyst is 2.5-3.5% of the weight of the polybrominated benzene.
3. The method for preparing bromobenzene from a polybrominated benzene mixture according to claim 1, characterized in that in the compounding, the weight ratio of titanium tetrachloride, aluminum trichloride, neodymium trichloride, hollow mesoporous silica microspheres, phthalic acid, N-dimethylformamide DMF is 20-22:13-15:7-8:25-30:35-38:1000-1200;
the particle size of the hollow mesoporous silica microsphere is 100-120nm.
4. The method for preparing bromobenzene from a mixture of polybrominated benzenes according to claim 1, characterized in that in the one treatment, the volume concentration of the ethanol solution is 40-50%;
and after the silane coupling agent A-151 and the silane coupling agent A-172 are added dropwise, the mixture is kept warm and stirred for 5-6 hours.
5. The method for preparing bromobenzene from a polybrominated benzene mixture according to claim 1, characterized in that in the one-time treatment, the weight ratio of the complex, the ethanol solution, the silane coupling agent A-151 and the silane coupling agent A-172 is 25-30:300-320:3-3.5:1-1.2.
6. The method for preparing bromobenzene from a polybrominated benzene mixture according to claim 1, characterized in that in the secondary treatment, the stirring temperature is raised to 55-65 ℃ and then the stirring time is kept for 5-6h;
the weight ratio of polysorbate-80, N-heptane, methacrylamide, vinylglycine, N' -methylenebisacrylamide, primary treatment substance and azodiisobutyronitrile is 1.2-1.5:120-130:0.55-0.65:1.6-1.8:2-2.5:10-12:0.25-0.3.
7. The method for preparing bromobenzene from a mixture of polybrominated benzenes according to claim 1, characterized in that the benzene dropping rate in the secondary reaction is 20-25mL/min;
after stopping dripping benzene, keeping the temperature and stirring for 20-40min.
8. The method for preparing bromobenzene from the polybrominated benzene mixture according to claim 1, wherein the post-treatment method is that solid matters in the secondary reactant are filtered out and then are introduced into an atmospheric distillation device, the temperature is raised to 138-140 ℃, and unreacted benzene and light component impurities are removed by heat preservation distillation; continuously heating to 155-157 ℃, preserving heat and distilling, controlling the reflux ratio to be 1:2.5-3, condensing and collecting light components to prepare bromobenzene.
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