CN113045379A - Method for co-producing mesitylene and durene by alkylation-isomerization of C8 or C9 aromatic hydrocarbon - Google Patents

Method for co-producing mesitylene and durene by alkylation-isomerization of C8 or C9 aromatic hydrocarbon Download PDF

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CN113045379A
CN113045379A CN202110347546.4A CN202110347546A CN113045379A CN 113045379 A CN113045379 A CN 113045379A CN 202110347546 A CN202110347546 A CN 202110347546A CN 113045379 A CN113045379 A CN 113045379A
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tower
rectifying tower
mesitylene
alkylation
isomerization
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CN113045379B (en
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曹正国
荆晓平
王福
李江华
陈佳佳
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Jiangsu Zhengdan Chemical Industry Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
    • C07C2/86—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon
    • C07C2/862—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon the non-hydrocarbon contains only oxygen as hetero-atoms
    • C07C2/864—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon the non-hydrocarbon contains only oxygen as hetero-atoms the non-hydrocarbon is an alcohol
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
    • C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
    • C07C5/27—Rearrangement of carbon atoms in the hydrocarbon skeleton
    • C07C5/2729—Changing the branching point of an open chain or the point of substitution on a ring
    • C07C5/2732—Catalytic processes
    • C07C5/2737—Catalytic processes with crystalline alumino-silicates, e.g. molecular sieves
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/005—Processes comprising at least two steps in series
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2529/00—Catalysts comprising molecular sieves
    • C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays
    • C07C2529/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • C07C2529/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • C07C2529/26—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
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    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2529/00—Catalysts comprising molecular sieves
    • C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays
    • C07C2529/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • C07C2529/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11

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Abstract

The invention relates to a method for co-producing mesitylene and durene by alkylation-isomerization of C8 or C9 aromatic hydrocarbon in the technical field of organic chemical production, which comprises the steps of carrying out alkylation reaction on C8 or C9 aromatic hydrocarbon and methanol to generate rich mesitylene and durene liquid; obtaining trimethylbenzene and durene through multiple fractional distillation, feeding the materials of pseudocumene, hemimellitene, pseudocumene and durene separated in the reaction back into an isomerization reactor to carry out isomerization reaction to generate rich mesitylene and durene, and circularly separating to obtain the pseudocumene and the durene. When the method is used for production, the product selectivity is high, the byproducts are few, the quality of the finished product is stable, and the method is suitable for industrial production.

Description

Method for co-producing mesitylene and durene by alkylation-isomerization of C8 or C9 aromatic hydrocarbon
Technical Field
The invention relates to a production method of mesitylene and durene, belonging to the technical field of organic chemical production.
Background
Mesitylene, chemical name is 1, 3, 5-trimethylbenzene, boiling point is 164.60 ℃, is colorless transparent liquid, is insoluble in water, is soluble in ethanol, and can be dissolved in benzene, ether and acetone in any proportion. Mesitylene is an important chemical raw material, can be subjected to oxidation, amination, sulfonation, nitration, alkylation and condensation reaction to prepare mesitylene tricarboxylic acid, trimebutidine and 2, 4, 6-trimethylphenol important fine chemical products which are respectively used for producing alkyd resin, plasticizer, unsaturated polyester, modified fiber, film and the like; an antioxidant 330; reactive brilliant blue, acid dye, K-3R and other dye intermediates; ultraviolet absorbers, and the like.
At present, the preparation method of mesitylene mainly comprises a synthesis method and a separation and purification method. The first synthesis method is classified into an isomerization method and an alkylation method: the isomerization method is to use the pseudocumene as the raw material to carry out isomerization reaction to generate the mesitylene; the alkylation method adopts C9 aromatic mesitylene enrichment liquid and propylene to obtain mesitylene through multiple alkylation or a combined alkylation method of propylene and isobutene. The second separation and purification method is to directly rectify and separate the mesitylene contained in the mixed aromatic hydrocarbon of C9, which is a by-product produced by catalytic reforming, ethylene and paraxylene devices in petrochemical engineering, as a raw material. The C9 mixed aromatics, which are a large amount of by-products, generally contain 6-12% mesitylene.
The chinese patent CN1210238C discloses a method for co-producing mesitylene and durene from xylene, pseudocumene and durene. Belongs to the production technology of mesitylene. The method comprises the steps of taking dimethylbenzene, pseudocumene and tetramethylbenzene as raw materials, taking anhydrous aluminum trichloride as a catalyst, carrying out isomerization reaction under normal pressure to obtain reaction liquid containing a mesitylene product, washing with water, carrying out alkali washing, sending to a rectifying tower for separation to obtain the mesitylene product with the purity of 98.5%, adding chloromethane into recycled di-tetramethylbenzene for alkylation reaction, washing with water, carrying out alkali washing, sending to the rectifying tower for separation to obtain the mesitylene product with the purity of 98.5%.
The Chinese invention patent CN1775714A discloses a method for producing high-purity mesitylene by adopting a combined alkylation method of propylene and isobutene, which comprises the following steps: placing a C9 aromatic hydrocarbon mixture of concentrated mesitylene fractions with the boiling range of 161-169 ℃ in a reaction kettle; adding catalyst anhydrous aluminum trichloride and cocatalyst ferric trichloride into the reaction kettle, and uniformly stirring; heating the reaction kettle to 40-70 ℃ under normal pressure, and continuously introducing alkylating agents of propylene and isobutene; after the reaction is finished, placing the mixture into a washing kettle, adding water, repeatedly washing the mixture to be neutral, settling and separating the mixture, and drying the mixture.
The Master thesis at Tianjin university reports a process flow for producing high-purity mesitylene by using pseudocumene as a raw material. The process adopts a method of organically combining a non-hydrocatalytic isomerization technology of the pseudocumene and a separation means of precise rectification, and is unique and feasible. The non-hydrocatalyzing isomerization reaction test is carried out in a designed tubular reactor by using a developed M-2 type composite mordenite catalyst and taking high-purity pseudocumene arene as a raw material. The experimental result shows that the reaction temperature is 300-320 ℃, the reaction pressure is 1.0-1.6MPa, and the volume space velocity is 1.5-2.0h-1Under the condition, the conversion per pass of the pseudocumene is about 38%, the selectivity of the pseudocumene is 70%, the catalyst has high catalytic activity and selectivity, and the content of the methyl ethyl benzene is not increased after the reaction.
The research of the Master thesis of Nanjing university adopts an extractive distillation method to produce the mesitylene-durene. The pretreatment is carried out by adopting an intermittent rectification method; determining the optimal operation condition by measuring a distillation temperature and composition relation curve so as to ensure that the content and the yield of the mesitylene are higher; the pretreated raw material mainly contains mesitylene, o-methyl-ethylbenzene and meta-trimethylbenzene. The solvent, binary and ternary vapor-liquid equilibrium data and simulation results provided by the method provide theoretical basis for pilot-scale test and industrial application of co-production of mesitylene and durene by an extractive distillation method.
The synthesis method has the problems of high energy consumption, more side reactions, complex post-treatment and the like. Meanwhile, the separation and purification method has small difference between the boiling points of the mesitylene (the boiling point is 164.60 ℃) and the o-methyl ethylbenzene (the boiling point is 164.18 ℃), so that the rectification method is difficult to obtain the high-purity mesitylene.
Durene is an important organic chemical raw material and is mainly used for producing pyromellitic dianhydride. Pyromellitic dianhydride is an important raw material for synthesizing polyimide polymers. The polyimide has excellent electrical insulation performance, high temperature resistance and radiation resistance and can be widely applied to aerospace industry, atomic energy industry and electromechanical industry. In addition, pyromellitic dianhydride is also an important raw material for high-quality plasticizers, curing agents and powder coating matting agents.
The technological synthetic route of durene mainly comprises two types of separation and purification methods and a chemical synthesis method, wherein one type of separation and purification method is to separate and purify by-products in the processing process of petroleum and coal, mainly heavy components of gasoline prepared from methanol or C10 heavy aromatic hydrocarbon, as raw materials; the other is a chemical synthesis method which mainly comprises alkylation, disproportionation reaction and the like. The alkylation method has the advantages of low cost, no corrosion to equipment, large product scale and the like, and is widely concerned.
Disclosure of Invention
The invention aims to provide a method for co-producing mesitylene and durene by alkylation-isomerization of C8 or C9 aromatic hydrocarbon, so that the mesitylene and durene products have high selectivity, few byproducts and stable finished product quality, and are suitable for industrial production.
The purpose of the invention is realized as follows: a method for co-producing mesitylene and durene by C8 or C9 aromatic alkylation-isomerization sequentially comprises the following steps:
1) premixing and heat exchanging C8 or C9 aromatic hydrocarbon and methanol, and then introducing into an alkylation reactor for alkylation reaction to generate rich mesitylene and durene solution;
2) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is minus 0.08 to minus 0.09MPa, the temperature at the top of the tower is 120-plus-130 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged from the top of the tower, the temperature at the bottom of the tower is 150-plus-160 ℃, and trimethylbenzene and tetramethylbenzene are discharged from the bottom of the tower; trimethylbenzene is its alkylation reaction product for C8 aromatics and xylene is a by-product of the reaction for C9 aromatics;
3) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is minus 0.08 to minus 0.09MPa, the temperature at the top of the rectifying tower is 100 plus materials, and xylene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature at the bottom of the tower is 130-140 ℃, and a trimethylbenzene material is discharged from the bottom of the tower;
4) the trimethylbenzene material at the bottom of the second rectifying tower enters a third rectifying tower, the vacuum degree of the top of the third rectifying tower is minus 0.08 to minus 0.09MPa, the temperature of the top of the third rectifying tower is 120-plus 130 ℃, the discharge of a gas phase port at the top of the tower is collected, a mesitylene finished product is obtained after condensation, and the mesitylene finished product is fed into a storage tank; the temperature of the three tower bottoms of the rectifying tower is 140-;
5) feeding the tower bottom material of the first rectifying tower into a fourth rectifying tower, wherein the tower top vacuum degree of the fourth rectifying tower is-0.08 to-0.09 MPa, the tower top rectifying temperature is 130-; the temperature of the bottom of the rectifying tower IV is 160-170 ℃, and tetramethylbenzene material is discharged from the bottom of the rectifying tower IV;
6) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 to-0.09 MPa, the tower top rectifying temperature is 150-160 ℃, collecting the effluent of a gas phase port at the tower top, and condensing to obtain a durene finished product; the temperature of the bottom of the rectifying tower V is 170-180 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the bottom of the rectifying tower V;
7) and the pseudocumene, hemimellitene, pseudocumene and hemimellitene materials discharged from the bottoms of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor to carry out isomerization reaction to generate rich mesitylene and durene solution, and the rich mesitylene and durene solution generated by the isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction are converged and then flow into the first rectifying tower to carry out circular fractionation.
Further, when the alkylation reaction is carried out in the step 1), the dosage volume ratio of the C8 or C9 aromatic hydrocarbon to the methanol is (4.0-12.0): 1.0, the reaction pressure is 1.0-1.8MPa, the reaction temperature is 320-400 ℃, and the volume space velocity of C8 or C9 aromatic hydrocarbon is 0.5-3.0h-1The alkylation catalyst is selected from ZSM-5 molecular sieve, and the dosage is as follows: 0.02-3.5% of the weight of the raw materials.
Further, the isomerization reaction in the step 6) is carried out, the reaction pressure is 0.8-1.4MPa, the reaction temperature is 270--1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.03-0.25% by weight of the reaction mass entering the isomerization reactor.
The C8 aromatic hydrocarbon consists of o-xylene, m-xylene and p-xylene, and the mass content of each component in the C8 aromatic hydrocarbon is 35% or more of o-xylene or more and 10% or more, 75% or more of m-xylene or more and 50% or more, and 40% or more of p-xylene or more and 15% or more.
The C9 aromatic hydrocarbon consists of mesitylene, pseudocumene and hemimellitene, and the mass content of each component in the C9 aromatic hydrocarbon is 70% or more of mesitylene and more than 7%, 88% or more of pseudocumene and more than 25%, and 68% or more of hemimellitene and more than 5%.
And the bottom outlet of the alkylation reactor is connected to the middle part of the first rectifying tower after passing through the tube pass of the first discharging heat exchanger, the bottom outlet of the isomerization reactor is connected to the middle part of the second discharging heat exchanger after passing through the tube pass of the second discharging heat exchanger, a reaction raw material C8 or C9 aromatic hydrocarbon and methanol is fed from the top of the alkylation reactor after passing through the shell passes of the first discharging heat exchanger and the second discharging heat exchanger which are connected in parallel, and the shell pass of the feeding heat exchanger is connected with a steam system.
The steam system comprises a heating furnace and a steam packet, an outlet of the heating furnace is connected with an inlet of the steam packet through a shell pass of the feeding heat exchanger, and an outlet of the steam packet is connected with an inlet of the heating furnace.
The invention has the beneficial effects that: the conversion per pass of C8 or C9 arene is about 10-50%, the selectivity of mesitylene or durene is 50-90%, the purity of mesitylene is 98.5-99.9%, and the purity of durene is 99.5-99.9%. By the co-production mode, the product conversion rate is high, the product selectivity is high, the byproducts are few, the quality of the finished product is stable, the method is suitable for industrial production, and the economic benefit is obvious.
Drawings
FIG. 1 is a process flow diagram of the present invention.
In the figure, 1 steam drum, 2 feeding heat exchanger, 3 alkylation reactor, 4 isomerization reactor, 5 rectifying tower I, 6 condenser, 7 water knockout drum, 8 rectifying tower II, 9 rectifying tower III, 10 rectifying tower IV, 11 rectifying tower V, 12 discharging heat exchanger I, 13 heating furnace, 14 discharging heat exchanger II.
Detailed Description
FIG. 1 shows a process flow diagram of the present invention.
The steam system comprises a heating furnace 13 and a steam packet 1, wherein the outlet of the heating furnace 13 is connected with the inlet of the steam packet 1 through the shell side of a feeding heat exchanger 2, and the outlet of the steam packet 1 is connected with the inlet of the heating furnace 13.
The bottom outlet of the alkylation reactor 3 is connected to the middle part of the rectifying tower 5 through the tube pass of the first discharging heat exchanger 12, the bottom outlet of the isomerization reactor 4 is connected to the middle part of the second discharging heat exchanger 14 through the tube pass of the second discharging heat exchanger 14, the reaction raw material C8 or the mixture of C9 aromatic hydrocarbon and methanol passes through the tube pass of the first discharging heat exchanger 12 and the shell pass of the second discharging heat exchanger 14 which are connected in parallel, then passes through the tube pass of the feeding heat exchanger 2, and then is fed from the top of the alkylation reactor 3, and the shell pass of the feeding heat exchanger 2 is connected with a steam system.
The rectifying tower comprises five rectifying towers I5-five rectifying towers II 11 in total, a gas phase outlet at the top of the rectifying tower I5 is connected to a water separator 7 after passing through a condenser 6, an organic component outlet at the upper part of the water separator 7 is connected to a middle inlet of a rectifying tower II 8, and a tower bottom outlet of the rectifying tower I5 is connected to a middle inlet of a rectifying tower IV 10; the top gas phase outlet of the second rectifying tower 8 is connected to the top inlet of the alkylation reactor 3; the bottom outlet of the second rectifying tower 8 is connected to the middle inlet of the third rectifying tower 9, and the top of the third rectifying tower 9 is a mesitylene outlet; the top outlet of the rectifying tower IV 10 is connected to the middle inlet of the rectifying tower III 9, the bottom outlet of the rectifying tower IV 10 is connected to the middle inlet of the rectifying tower V11, the top of the rectifying tower V11 is an outlet of durene, and the bottom outlet of the rectifying tower III 9 and the bottom outlet of the rectifying tower V11 are connected to the top inlet of the isomerization reactor 4.
Example 1:
alkylation: raw material C8 aromatic hydrocarbon and methanol (volume ratio is 4:1, volume space)The speed is 0.5h-1) The raw material after vaporization is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage is as follows: 0.02% of the weight of the reaction raw materials; the C8 aromatic hydrocarbon consists of o-xylene, m-xylene and p-xylene, wherein in the C8 aromatic hydrocarbon, the mass content of each component is 35% of o-xylene, 50% of m-xylene and 15% of p-xylene; the reaction pressure is 1.0MPa, the reaction temperature is 320-400 ℃, and the volume space velocity of C8 aromatic hydrocarbon is 0.5-3.0h-1。
And discharging the alkylation enrichment liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is-0.08 MPa, the temperature at the top of the tower is 120 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 150 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is-0.08 MPa, the temperature at the top of the rectifying tower is 100 ℃, and dimethylbenzene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature of the tower bottom is 130 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.08 MPa, the temperature at the top of the rectifying tower III is 120 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 140 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.08 MPa, the tower top rectifying temperature is 130 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and feeding the trimethylbenzene material into a rectifying tower III for further separation; the tower bottom temperature of the rectifying tower IV is 160 ℃, and tetramethylbenzene material is discharged from the tower bottom;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 MPa, the tower top rectifying temperature is 150 ℃, collecting the effluent of a gas phase port at the tower top, and condensing to obtain a durene finished product; the temperature of the bottom of the rectifying tower V is 170 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the bottom of the rectifying tower V.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene from the bottom of the rectifying tower III and the rectifying tower V are fed back into the isomerization reactor to be subjected to isomerization reaction to generate rich mesitylene and durene solution, the reaction pressure is 0.8MPa, the reaction temperature is 270 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 0.25-1.0h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.03% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 aromatic hydrocarbon reaches 20%, the selectivity of the mesitylene in the alkylation reaction liquid reaches 70%, the purity of the final rectified and refined mesitylene finished product reaches 98.50%, and the purity of the mesitylene is 99.5%.
Example 2:
alkylation: the raw material C9 aromatic hydrocarbon (volume ratio 4.5:1, volume space velocity of 1 h)-1) And the vaporized raw material is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage of the catalyst is 0.5 percent of the total weight of the raw material. The C9 aromatic hydrocarbon consists of mesitylene, pseudocumene and hemimellitene, wherein in the C9 aromatic hydrocarbon, the mass contents of the components are 7% of mesitylene, 88% of pseudocumene and 5% of hemimellitene; the alkylation reaction is carried out under 1.2MPa and 350 ℃. And discharging an alkylation liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
And discharging the alkylation enrichment liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is-0.09 MPa, the temperature at the top of the tower is 130 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 160 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is-0.09 MPa, the temperature at the top of the rectifying tower is 110 ℃, and dimethylbenzene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature of the tower bottom is 140 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.09 MPa, the temperature at the top of the rectifying tower III is 130 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 150 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.09 MPa, the tower top rectifying temperature is 140 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and feeding the trimethylbenzene material into a rectifying tower III for further separation; the temperature of the bottom of the rectifying tower IV is 170 ℃, and tetramethylbenzene material is discharged from the bottom of the rectifying tower IV;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is 0.09MPa, the tower top rectifying temperature is 160 ℃, collecting the discharge of a gas phase port at the tower top, and condensing to obtain a durene finished product; the tower bottom temperature of the rectifying tower V is 180 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the tower bottom.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene from the bottom of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor for isomerization reaction to generate rich pseudocumene and tetratoluene liquid, the reaction pressure is 0.8-1.4MPa, the reaction temperature is 270-310 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 0.25-1.0h-1Isomerization catalystSelected from Ni-W hydrogen mordenite in the following dosage: 0.03-0.25% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C9 aromatic hydrocarbon reaches 27%, the selectivity of mesitylene in the alkylation reaction liquid reaches 76%, the purity of the final rectified and refined mesitylene finished product reaches 99.15%, and the purity of the mesitylene is 99.7%.
Example 3:
alkylation: the raw material C8 aromatic hydrocarbon (volume ratio 5:1, volume space velocity 2 h)-1) And the vaporized raw material is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage of the catalyst is 1 percent of the total weight of the raw material. The C8 aromatic hydrocarbon consists of o-xylene, m-xylene and p-xylene, wherein in the C8 aromatic hydrocarbon, the mass content of each component is 10% of o-xylene, 75% of m-xylene and 15% of p-xylene; the alkylation reaction was carried out at 1.3MPa and 340 ℃. And discharging an alkylation liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
And discharging the alkylation enrichment liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is-0.08 MPa, the temperature at the top of the tower is 130 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 150 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is-0.09 MPa, the temperature at the top of the rectifying tower is 100 ℃, and dimethylbenzene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature of the tower bottom is 140 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.08 MPa, the temperature at the top of the rectifying tower III is 130 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 140 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.08 MPa, the tower top rectifying temperature is 140 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and feeding the trimethylbenzene material into a rectifying tower III for further separation; the tower bottom temperature of the rectifying tower IV is 160 ℃, and tetramethylbenzene material is discharged from the tower bottom;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 MPa, the tower top rectifying temperature is 160 ℃, collecting the effluent of a gas phase port at the tower top, and condensing to obtain a durene finished product; the temperature of the bottom of the rectifying tower V is 170 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the bottom of the rectifying tower V.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene from the bottom of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor for isomerization reaction to generate rich pseudocumene and tetratoluene liquid, the reaction pressure is 0.8-1.4MPa, the reaction temperature is 270-310 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 0.25-1.0h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.03-0.25% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 aromatic hydrocarbon reaches 35%, the selectivity of mesitylene in the alkylation reaction liquid reaches 80%, the purity of the final rectified and refined mesitylene finished product reaches 99.28%, and the purity of the mesitylene is 99.8%.
Example 4:
alkyl radicalAnd (3) conversion: the raw material C9 aromatic hydrocarbon (volume ratio 5.5:1, volume space velocity 3 h)-1) And the vaporized raw material is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage of the catalyst is 2 percent of the total weight of the raw material. The C9 aromatic hydrocarbon consists of mesitylene, pseudocumene and hemimellitene, wherein the mass content of each component in the C9 aromatic hydrocarbon is 70% of mesitylene, 25% of pseudocumene and 5% of hemimellitene; the alkylation reaction was carried out at 1.5MPa and 350 ℃. And discharging an alkylation liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
And discharging the alkylation enrichment liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is minus 0.08 to minus 0.09MPa, the temperature at the top of the tower is 120-plus-130 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged from the top of the tower, the temperature at the bottom of the tower is 150-plus-160 ℃, and trimethylbenzene and tetramethylbenzene are discharged from the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is minus 0.08 to minus 0.09MPa, the temperature at the top of the rectifying tower is 100 plus materials, and xylene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature at the bottom of the tower is 130-140 ℃, and a trimethylbenzene material is discharged from the bottom of the tower;
3) the trimethylbenzene material at the bottom of the second rectifying tower enters a third rectifying tower, the vacuum degree of the top of the third rectifying tower is minus 0.08 to minus 0.09MPa, the temperature of the top of the third rectifying tower is 120-plus 130 ℃, the discharge of a gas phase port at the top of the tower is collected, a mesitylene finished product is obtained after condensation, and the mesitylene finished product is fed into a storage tank; the temperature of the three tower bottoms of the rectifying tower is 140-;
4) feeding the tower bottom material of the first rectifying tower into a fourth rectifying tower, wherein the tower top vacuum degree of the fourth rectifying tower is-0.08 to-0.09 MPa, the tower top rectifying temperature is 130-; the temperature of the bottom of the rectifying tower IV is 160-170 ℃, and tetramethylbenzene material is discharged from the bottom of the rectifying tower IV;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 to-0.09 MPa, the tower top rectifying temperature is 150-160 ℃, collecting the effluent of a gas phase port at the tower top, and condensing to obtain a durene finished product; the temperature of the bottom of the rectifying tower V is 170-180 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the bottom of the rectifying tower V.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene from the bottom of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor for isomerization reaction to generate rich pseudocumene and tetratoluene liquid, the reaction pressure is 0.8-1.4MPa, the reaction temperature is 270-310 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 0.25-1.0h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.03-0.25% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 or C9 aromatic hydrocarbon reaches 37 percent, the selectivity of the mesitylene in the alkylation reaction liquid reaches 87 percent, the purity of the final rectified and refined mesitylene finished product reaches 99.28 percent, and the purity of the mesitylene is 99.76 percent.
Example 5:
alkylation: raw material C8 aromatic hydrocarbon and methanol (volume ratio is 6:1, volume space velocity is 1 h)-1) The raw material after vaporization is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage of the catalyst is 3.5 percent of the total weight of the raw material. The C8 aromatic hydrocarbon consists of o-xylene, m-xylene and p-xylene, and the mass content of each component in the C8 aromatic hydrocarbon is 10% of o-xylene, 50% of m-xylene and 40% of p-xylene; the alkylation reaction is carried out under 1.6Mpa and 360 ℃. Alkylation reactionThe obtained alkylated liquid is discharged from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is minus 0.08 to minus 0.09MPa, the temperature at the top of the tower is 120 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 150 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is minus 0.08 to minus 0.09MPa, the temperature at the top of the rectifying tower is 105 ℃, xylene is discharged from the top of the rectifying tower, and the xylene returns to the alkylation reactor; the temperature of the tower bottom is 130 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.08 to-0.09 MPa, the temperature at the top of the rectifying tower III is 130 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 140 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.08 to-0.09 MPa, the tower top rectifying temperature is 130 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and then feeding the trimethylbenzene material into a rectifying tower III for further separation; the temperature of the bottom of the rectifying tower IV is 160-170 ℃, and tetramethylbenzene material is discharged from the bottom of the rectifying tower IV;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 to-0.09 MPa, the tower top rectifying temperature is 160 ℃, collecting the discharge of a gas phase port at the tower top, and condensing to obtain a durene finished product; the tower bottom temperature of the rectifying tower V is 180 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the tower bottom.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene from the bottom of the third rectifying tower and the fifth rectifying tower are fed back into the isomerization reactor to be isomerized into rich mesitylene and durene solution, the reaction pressure is 1.2MPa, the reaction temperature is 275 ℃, the pseudocumene, hemimellitene, pseudocumene, tetratoluene and tetramethylbenzene are obtained,The volume space velocity of the continuous tetramethylbenzene is 0.5h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.15% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 or C9 aromatic hydrocarbon reaches 50%, the selectivity of mesitylene in the alkylation reaction liquid reaches 75%, the purity of the final rectified and refined mesitylene is as high as 98.67%, and the purity of the mesitylene is 99.6%.
Example 6:
alkylation: the raw material C9 aromatic hydrocarbon (volume ratio of 7:1, volume space velocity of 2 h)-1) And the vaporized raw material is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage of the catalyst is 3 percent of the total weight of the raw material. The C9 aromatic hydrocarbon consists of mesitylene, pseudocumene and hemimellitene, wherein in the C9 aromatic hydrocarbon, the mass content of each component is 7 percent of mesitylene, 25 percent of pseudocumene and 68 percent of hemimellitene; the alkylation reaction was carried out at 1.7MPa and 370 ℃. And discharging an alkylation liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is minus 0.08 to minus 0.09MPa, the temperature at the top of the tower is 125 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 150 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is minus 0.08 to minus 0.09MPa, the temperature at the top of the rectifying tower is 110 ℃, xylene is discharged from the top of the rectifying tower, and the xylene returns to the alkylation reactor; the temperature of the tower bottom is 140 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.08 to-0.09 MPa, the temperature at the top of the rectifying tower III is 130 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 140 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.08 to-0.09 MPa, the tower top rectifying temperature is 140 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and then feeding the trimethylbenzene material into a rectifying tower III for further separation; the tower bottom temperature of the rectifying tower IV is 160 ℃, and tetramethylbenzene material is discharged from the tower bottom;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 to-0.09 MPa, the tower top rectifying temperature is 160 ℃, collecting the discharge of a gas phase port at the tower top, and condensing to obtain a durene finished product; the temperature of the bottom of the rectifying tower V is 170 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the bottom of the rectifying tower V.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene materials discharged from the bottoms of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor to carry out isomerization reaction to generate rich mesitylene and durene solution, the reaction pressure is 0.8MPa, the reaction temperature is 270 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 0.25h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.05% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 or C9 aromatic hydrocarbon reaches 44%, the selectivity of mesitylene in the alkylation reaction liquid reaches 88%, the purity of the final rectified and refined mesitylene is as high as 98.78%, and the purity of the mesitylene is 99.59%.
Example 7:
alkylation: raw materials of C8 aromatic hydrocarbon and methanol (volume ratio is 8:1, volume ratio)The volume space velocity is 3h-1) The raw material after vaporization is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage of the catalyst is 2.5 percent of the total weight of the raw material. The C8 aromatic hydrocarbon consists of o-xylene, m-xylene and p-xylene, and the mass content of each component in the C8 aromatic hydrocarbon is 20% of o-xylene, 50% of m-xylene and 30% of p-xylene; the alkylation reaction is carried out under 1.0MPa and 380 ℃. And discharging an alkylation liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is minus 0.08 to minus 0.09MPa, the temperature at the top of the tower is 120 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 150 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is-0.08 MPa, the temperature at the top of the rectifying tower is 100 ℃, and dimethylbenzene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature of the tower bottom is 140 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.09 MPa, the temperature at the top of the rectifying tower III is 120 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 150 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.09 MPa, the tower top rectifying temperature is 135 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and feeding the trimethylbenzene material into a rectifying tower III for further separation; the tower bottom temperature of the rectifying tower IV is 160 ℃, and tetramethylbenzene material is discharged from the tower bottom;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 MPa, the tower top rectifying temperature is 155 ℃, collecting the discharge of a gas phase port at the tower top, and condensing to obtain a durene finished product; the tower bottom temperature of the rectifying tower V is 175 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the tower bottom.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene materials discharged from the bottoms of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor to carry out isomerization reaction to generate rich mesitylene and durene solution, the reaction pressure is 0.8MPa, the reaction temperature is 270 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 0.25h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.03% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 or C9 aromatic hydrocarbon reaches 47 percent, the selectivity of mesitylene in the alkylation reaction liquid reaches 77.5 percent, the purity of the final rectified and refined mesitylene product reaches 99.90 percent, and the purity of the mesitylene product reaches 99.92 percent.
Example 8:
alkylation: raw material C9 aromatic hydrocarbon and methanol (volume ratio of 10:1, volume space velocity of 2 h)-1) The raw material is vaporized by heat exchange with steam, the vaporized raw material is sent into a radial fixed bed reactor through an inlet pipe at the top of an alkylation reactor, a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, and the dosage of the catalyst is 0.1 percent of the total weight of the raw material. The C9 aromatic hydrocarbon consists of mesitylene, pseudocumene and hemimellitene, wherein in the C9 aromatic hydrocarbon, the mass content of each component is 35% of mesitylene, 40% of pseudocumene and 25% of hemimellitene; the alkylation reaction was carried out at 1.2MPa and 390 ℃. And discharging an alkylation liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is minus 0.08 to minus 0.09MPa, the temperature at the top of the tower is 120 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 150 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is minus 0.08 to minus 0.09MPa, the temperature at the top of the rectifying tower is 110 ℃, xylene is discharged from the top of the rectifying tower, and the xylene returns to the alkylation reactor; the temperature of the tower bottom is 130 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.08 to-0.09 MPa, the temperature at the top of the rectifying tower III is 120 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 140 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.08 to-0.09 MPa, the tower top rectifying temperature is 130 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and then feeding the trimethylbenzene material into a rectifying tower III for further separation; the temperature of the bottom of the rectifying tower IV is 170 ℃, and tetramethylbenzene material is discharged from the bottom of the rectifying tower IV;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 to-0.09 MPa, the tower top rectifying temperature is 160 ℃, collecting the discharge of a gas phase port at the tower top, and condensing to obtain a durene finished product; the temperature of the bottom of the rectifying tower V is 170 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the bottom of the rectifying tower V.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene materials discharged from the bottoms of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor to carry out isomerization reaction to generate rich mesitylene and durene solution, the reaction pressure is 1.4MPa, the reaction temperature is 300 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 1.0h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.03% by weight of the reaction mass entering the isomerization reactor. The rich sym-trimethylbenzene and sym-tetramethylbenzene solution produced by isomerization reaction and sym-trimethylbenzene and sym-tetramethylbenzene produced by alkylation reactionAnd after being converged, the rich tetramethylbenzene solution flows into a first rectifying tower for cyclic fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 or C9 aromatic hydrocarbon reaches 45.6 percent, the selectivity of the mesitylene in the alkylation reaction liquid reaches 78.8 percent, the purity of the final rectified and refined mesitylene product reaches 99.80 percent, and the purity of the mesitylene product reaches 99.85 percent.
Example 9:
alkylation: raw material C8 aromatic hydrocarbon and methanol (volume ratio is 12:1, volume space velocity is 2.0h-1) The raw material after vaporization is sent into a radial fixed bed reactor through an inlet pipe at the top of the alkylation reactor, and a ZSM-5 molecular sieve catalyst is filled in a radial annular cylinder of the radial fixed bed reactor, wherein the dosage of the catalyst is 3.5 percent of the total weight of the raw material. The C8 aromatic hydrocarbon consists of o-xylene, m-xylene and p-xylene, and the mass content of each component in the C8 aromatic hydrocarbon is 20% of o-xylene, 50% of m-xylene and 30% of p-xylene; the alkylation reaction is carried out under 1.8MPa and at 400 ℃. And discharging an alkylation liquid obtained by alkylation reaction from an outlet pipe at the bottom of the radial fixed bed reactor.
A rectification step:
1) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is-0.09 MPa, the temperature at the top of the tower is 125 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged at the top of the tower, the temperature at the bottom of the tower is 155 ℃, and trimethylbenzene and tetramethylbenzene are discharged at the bottom of the tower;
2) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is-0.08 MPa, the temperature at the top of the rectifying tower is 105 ℃, and dimethylbenzene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature of the tower bottom is 135 ℃, and a trimethylbenzene material is discharged from the tower bottom;
3) feeding the trimethylbenzene material at the bottom of the rectifying tower II into a rectifying tower III, wherein the vacuum degree at the top of the rectifying tower III is-0.08 MPa, the temperature at the top of the rectifying tower III is 125 ℃, collecting the discharge of a gas phase port at the top of the rectifying tower, condensing to obtain a mesitylene finished product, and feeding the mesitylene finished product into a storage tank; the temperature of the bottom of the third tower of the rectifying tower is 145 ℃, and the materials of pseudocumene and hemimellitene are discharged from the bottom of the rectifying tower;
4) feeding the tower bottom material of the rectifying tower I into a rectifying tower IV, wherein the tower top vacuum degree of the rectifying tower IV is-0.09 MPa, the tower top rectifying temperature is 135 ℃, collecting the discharge of a gas phase port at the tower top, condensing to obtain a trimethylbenzene material, and feeding the trimethylbenzene material into a rectifying tower III for further separation; the temperature of the bottom of the rectifying tower IV is 160-170 ℃, and tetramethylbenzene material is discharged from the bottom of the rectifying tower IV;
5) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 MPa, the tower top rectifying temperature is 155 ℃, collecting the discharge of a gas phase port at the tower top, and condensing to obtain a durene finished product; the tower bottom temperature of the rectifying tower V is 175 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the tower bottom.
And (3) isomerization reaction: the pseudocumene, hemimellitene, pseudotetratoluene and tetratoluene materials discharged from the bottoms of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor to carry out isomerization reaction to generate rich mesitylene and durene solution, the reaction pressure is 1.2MPa, the reaction temperature is 310 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudocumene and the tetratoluene is 0.8h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.25% by weight of the reaction mass entering the isomerization reactor. Gathering the rich mesitylene and durene solution generated by isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction, and then flowing into the first rectifying tower for circular fractionation.
The alkylation-rectification-isomerization-rectification is carried out according to the conditions, the conversion per pass of the raw material C8 or C9 aromatic hydrocarbon reaches 10%, the selectivity of mesitylene in the alkylation reaction liquid reaches 90%, the purity of the final rectified and refined mesitylene is as high as 99.50%, and the purity of the mesitylene is 99.88%.
The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.

Claims (7)

1. A method for co-producing mesitylene and durene by C8 or C9 aromatic alkylation-isomerization is characterized by sequentially comprising the following steps:
1) premixing and heat exchanging C8 or C9 aromatic hydrocarbon and methanol, and then introducing into an alkylation reactor for alkylation reaction to generate rich mesitylene and durene solution;
2) the enrichment solution after the alkylation reaction enters a first rectifying tower, the vacuum degree at the top of the tower is minus 0.08 to minus 0.09MPa, the temperature at the top of the tower is 120-plus-130 ℃, dimethylbenzene and a small amount of trimethylbenzene are discharged from the top of the tower, the temperature at the bottom of the tower is 150-plus-160 ℃, and trimethylbenzene and tetramethylbenzene are discharged from the bottom of the tower;
3) the material at the top of the rectifying tower I passes through a condenser and a water separator, the organic layer component enters a rectifying tower II, the vacuum degree at the top of the rectifying tower II is minus 0.08 to minus 0.09MPa, the temperature at the top of the rectifying tower is 100 plus materials, and xylene is discharged from the top of the rectifying tower and returns to the alkylation reactor; the temperature at the bottom of the tower is 130-140 ℃, and a trimethylbenzene material is discharged from the bottom of the tower;
4) the trimethylbenzene material at the bottom of the second rectifying tower enters a third rectifying tower, the vacuum degree of the top of the third rectifying tower is minus 0.08 to minus 0.09MPa, the temperature of the top of the third rectifying tower is 120-plus 130 ℃, the discharge of a gas phase port at the top of the tower is collected, a mesitylene finished product is obtained after condensation, and the mesitylene finished product is fed into a storage tank; the temperature of the three tower bottoms of the rectifying tower is 140-;
5) feeding the tower bottom material of the first rectifying tower into a fourth rectifying tower, wherein the tower top vacuum degree of the fourth rectifying tower is-0.08 to-0.09 MPa, the tower top rectifying temperature is 130-; the temperature of the bottom of the rectifying tower IV is 160-170 ℃, and tetramethylbenzene material is discharged from the bottom of the rectifying tower IV;
6) feeding the tower bottom material of the rectifying tower IV into a rectifying tower V, wherein the tower top vacuum degree of the rectifying tower V is-0.08 to-0.09 MPa, the tower top rectifying temperature is 150-160 ℃, collecting the effluent of a gas phase port at the tower top, and condensing to obtain a durene finished product; the temperature of the bottom of the rectifying tower V is 170-180 ℃, and heavy components of the partial tetramethylbenzene and the continuous tetramethylbenzene are discharged from the bottom of the rectifying tower V;
7) and the pseudocumene, hemimellitene, pseudocumene and hemimellitene materials discharged from the bottoms of the third rectifying tower and the fifth rectifying tower are returned to the isomerization reactor to carry out isomerization reaction to generate rich mesitylene and durene solution, and the rich mesitylene and durene solution generated by the isomerization reaction and the rich mesitylene and durene solution generated by alkylation reaction are converged and then flow into the first rectifying tower to carry out circular fractionation.
2. The process of claim 1, wherein said alkylation-isomerization of C8 or C9 aromatic hydrocarbons is used for the co-production of mesitylene and durene, characterized in that: when the alkylation reaction is carried out in the step 1), the dosage volume ratio of the C8 or C9 aromatic hydrocarbon to the methanol is (4.0-12.0): 1.0, the reaction pressure is 1.0-1.8MPa, the reaction temperature is 320-400 ℃, and the volume space velocity of C8 or C9 aromatic hydrocarbon is 0.5-3.0h-1The alkylation catalyst is selected from ZSM-5 molecular sieve, and the dosage is as follows: 0.02-3.5% of the weight of the raw materials.
3. The process of claim 1, wherein said alkylation-isomerization of C8 or C9 aromatic hydrocarbons is used for the co-production of mesitylene and durene, characterized in that: when the isomerization reaction is carried out in the step 6), the reaction pressure is 0.8-1.4MPa, the reaction temperature is 270-310 ℃, and the volume space velocity of the pseudocumene, the hemimellitene, the pseudotetramethylbenzene and the hemimellitene is 0.25-1.0h-1The isomerization catalyst is selected from Ni-W hydrogen mordenite, and the dosage is as follows: 0.03-0.25% by weight of the reaction mass entering the isomerization reactor.
4. The method for co-producing mesitylene and durene by alkylating C8 or C9 aromatic hydrocarbon according to claim 2, wherein the C8 aromatic hydrocarbon is composed of o-xylene, m-xylene and p-xylene, and the mass content of each component in the C8 aromatic hydrocarbon is 35% or more, 10% or more, 75% or more, 50% or more and 40% or more, 15% or more of o-xylene.
5. The method for the combined production of mesitylene and durene by the alkylation-isomerization of C8 or C9 aromatic hydrocarbon according to claim 2, wherein the C9 aromatic hydrocarbon comprises mesitylene, pseudocumene and hemimellitene, and the mass content of each component in the C9 aromatic hydrocarbon is 70% or more of mesitylene and 7% or more, 88% or more of pseudocumene and 25% or more, and 68% or more of hemimellitene and 5% or more.
6. A process for the alkylation-isomerization co-production of mesitylene, durene according to any one of claims 1-4, from C8 or C9 aromatic hydrocarbons, characterized in that: and the bottom outlet of the alkylation reactor is connected to the middle part of the first rectifying tower after passing through the tube pass of the first discharging heat exchanger, the bottom outlet of the isomerization reactor is connected to the middle part of the second discharging heat exchanger after passing through the tube pass of the second discharging heat exchanger, a reaction raw material C8 or C9 aromatic hydrocarbon and methanol is fed from the top of the alkylation reactor after passing through the shell passes of the first discharging heat exchanger and the second discharging heat exchanger which are connected in parallel, and the shell pass of the feeding heat exchanger is connected with a steam system.
7. The method for co-producing mesitylene and durene by alkylation-isomerization of C8 or C9 aromatic hydrocarbons according to claim 6, wherein the method comprises the following steps: the steam system comprises a heating furnace and a steam packet, an outlet of the heating furnace is connected with an inlet of the steam packet through a shell pass of the feeding heat exchanger, and an outlet of the steam packet is connected with an inlet of the heating furnace.
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