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CN117658761A - Dehydrogenation synthesis method and system of tert-butylstyrene - Google Patents

Dehydrogenation synthesis method and system of tert-butylstyrene Download PDF

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Publication number
CN117658761A
CN117658761A CN202211012702.2A CN202211012702A CN117658761A CN 117658761 A CN117658761 A CN 117658761A CN 202211012702 A CN202211012702 A CN 202211012702A CN 117658761 A CN117658761 A CN 117658761A
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tert
dehydrogenation
butylstyrene
auxiliary agent
tower
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肖哲
刘姝
潘罗其
余卫勋
彭涛
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Sinopec Baling Petrochemical Co ltd
China Petroleum and Chemical Corp
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Sinopec Baling Petrochemical Co ltd
China Petroleum and Chemical Corp
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    • 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
    • C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
    • C07C5/327—Formation of non-aromatic carbon-to-carbon double bonds only
    • C07C5/333—Catalytic processes
    • C07C5/3332—Catalytic processes with metal oxides or metal sulfides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
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    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/85—Chromium, molybdenum or tungsten
    • B01J23/88—Molybdenum
    • B01J23/887—Molybdenum containing in addition other metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/8872—Alkali or alkaline earth metals
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    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • 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
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00002—Chemical plants
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    • B01J2219/00006—Large-scale industrial plants
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    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
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    • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
    • C07C2523/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36
    • C07C2523/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • C07C2523/85—Chromium, molybdenum or tungsten
    • C07C2523/88—Molybdenum
    • C07C2523/887—Molybdenum containing in addition other metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36

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Abstract

The invention belongs to the field of chemical synthesis, and in particular relates to a dehydrogenation synthesis method of tert-butyl styrene, which comprises the steps of carrying out catalytic dehydrogenation reaction on a mixed system containing tert-butyl ethylbenzene, an auxiliary agent, water and an iron-based catalyst at the temperature of 500-600 ℃, and then separating to obtain the tert-butyl styrene; the auxiliary agent is at least one of cyclohexane, cyclohexyl ethane and methylcyclohexane. The process and the conditions are combined, so that the side reaction of the isopropenyl styrene in the dehydrogenation process can be reduced synergistically, and the yield and the purity of the tert-butyl styrene can be improved.

Description

Dehydrogenation synthesis method and system of tert-butylstyrene
Technical Field
The invention relates to the field of chemical synthesis, in particular to the field of preparation of tert-butylstyrene by catalytic dehydrogenation of tert-butylethylbenzene.
Background
In industrially produced plastic varieties, polystyrene stands in front of it, based on yield and performance. However, with the rapid development of the economy in China, the application field of the product is continuously expanded, the demand is increased, and the quality requirement is increased. Today, the rapid development of high and new technologies puts higher demands on certain special properties of the polymers, and is therefore of great importance for modification research of the polymers.
Styrene is easily modified due to the presence of benzene rings and is of a wide variety. In addition, styrene has strong volatility and can cause certain harm to the environment, and the introduction of relatively large groups into benzene rings is an effective method for reducing the volatility of the styrene. Tert-butyl styrene is a derivative of styrene, and because of the large steric hindrance of tert-butyl, the degree of freedom of molecular thermal motion of a high polymer chain can be reduced, so that the glass transition temperature of a homopolymer is greatly improved, and is about 42 ℃ higher than that of polystyrene. In addition, the increase of the alkyl chain length is beneficial to the solubility of the catalyst in aliphatic hydrocarbon, so that the catalyst can be dissolved in various aromatic hydrocarbon solvents. The excellent physical and chemical properties of the tert-butyl styrene lead the tert-butyl styrene to have potential application prospect in the development of novel materials in various fields such as synthetic rubber, synthetic resin and the like.
Currently, the synthesis method of tert-butylstyrene mainly has two paths: (1) Tert-butylstyrene, ethylene and oxygen are generated in the presence of a catalyst; (2) Tert-butylethylbenzene is produced by dehydrogenation in the presence of a dehydrogenation catalyst.
US3932549 discloses a process for synthesizing tert-butylethylbenzene from tert-butylbenzene, ethylene and oxygen in the presence of a noble metal palladium catalyst, which uses a noble metal palladium catalyst and is expensive, thereby increasing the production cost; at the same time, the reaction pressure reaches 100Kg/cm 2 The requirements on the reaction device are too high and too highThe pressure makes the process safety index low.
US3631213 discloses the catalytic dehydrogenation of tert-butylethylbenzene to tert-butylstyrene using an iron-based catalyst at a temperature of 540-700 ℃ and with a high amount of by-products of the dehydrogenation reaction. The raw materials are easy to generate cracking reaction at high temperature, so that the isopropenyl styrene generated in the dehydrogenation product has higher impurity content, and the isopropenyl styrene has similar properties with the tertiary butyl styrene, so that the isopropenyl styrene cannot be completely separated by common vacuum rectification, and the polymerization reaction of the tertiary butyl styrene product is unfavorable when the isopropenyl styrene product has the impurity content exceeding 100ppm. GB2163773 reports the extractive distillation of impurities using sulfolane as solvent and US4982034 discloses the use of activated carbon adsorption to remove isopropenylstyrene produced during dehydrogenation. Both the above methods are relatively complicated to operate and increase the reaction energy consumption, so that the content of the impurity isopropenyl styrene needs to be strictly controlled in the process of synthesizing the tert-butyl styrene.
The tert-butylstyrene is prepared by oxidative dehydrogenation of tert-butylethylbenzene with oxygen using different phosphates as catalysts in US4363748, GB2068767, US4291184, US4363748, US 4393263. Although the reaction temperature of the disclosed methods is relatively low (350-600 ℃), the selectivity of the tert-butylstyrene is high, the isopropenylstyrene impurity is less generated, and the safety index of the operation process is low due to the participation of oxygen in the reaction, so that the method is not beneficial to industrial production.
Disclosure of Invention
In order to solve the problems that the side reaction of the isopropenyl styrene is easy to occur and the yield and purity of the target product are not ideal in the process of preparing the tert-butylstyrene by dehydrogenating tert-butylethylbenzene, the invention provides a dehydrogenation synthesis method of the tert-butylstyrene, and aims to effectively inhibit the side reaction of the isopropenyl styrene and improve the yield and purity of the target product.
A second object of the present invention is to provide a synergy of implementing the dehydrogenation-synthesis method.
Unlike conventional ethylbenzene dehydrogenation, tert-butyl ethylbenzene is easy to produce isopropenyl styrene by-product in the dehydrogenation preparation process due to the structural characteristics of substituent groups, and the yield and purity of the product are affected, and the following solution is provided in the invention:
a dehydrogenation synthetic method of tert-butyl styrene comprises the steps of carrying out catalytic dehydrogenation reaction on a mixed system containing tert-butyl ethylbenzene, an auxiliary agent, water and an iron-based catalyst at the temperature of 500-600 ℃, and then separating to obtain tert-butyl styrene;
the auxiliary agent is at least one of cyclohexane, cyclohexyl ethane and methylcyclohexane.
The research of the invention shows that the iron-based catalyst is innovatively adopted, and the auxiliary agent and the catalytic dehydrogenation temperature are combined to control, so that the synergy can be realized, the side reactions of the isopropenyl styrene and the like can be effectively inhibited, and the yield and purity of the tert-butyl styrene can be improved.
In the invention, the tert-butylethylbenzene is at least one of p-tert-butylethylbenzene and m-tert-butylethylbenzene.
In the invention, the iron-based catalyst, the auxiliary agent and the temperature are combined to cooperatively solve the side reaction of the isopropenyl styrene in the dehydrogenation stage of the tert-butylethylbenzene, and the key of improving the yield and purity of the tert-butylstyrene product is that.
According to the invention, the auxiliary agent is used, and the catalyst and the temperature are combined, so that the synergy can be realized unexpectedly, the side reaction of the isopropyl styrene can be effectively reduced, and in addition, the auxiliary agent does not dehydrogenate, thereby being beneficial to remarkably improving the conversion selectivity and effect of the tert-butyl styrene.
In the invention, the weight ratio of the tert-butylethylbenzene to the auxiliary agent to the water is 1-4: 1:3 to 7.
In the present invention, the iron-based catalyst contains Fe 2 O 3 、K 2 O、Ce 2 O 3 、MoO 3 CaO and MgO.
In the invention, in the iron-based catalyst, K is calculated according to the weight percentage 2 O4～9％；Ce 2 O 3 6～11％；MoO 3 1 to 5 percent; 0.5 to 5 percent of CaO; 0.5 to 5 percent of MgO; the balance of Fe 2 O 3 (e.g., 66-79%).
In the present invention, the dehydrogenation reaction may be either batch or continuous, and for example, the continuous reaction may be carried out by means of a conventional gas-solid reaction apparatus.
Preferably, in the preparation method, tert-butylethylbenzene, an auxiliary agent and water are preheated and gasified in advance, and then the gasified mixture is contacted with an iron-based catalyst, and catalytic dehydrogenation reaction is carried out at the temperature.
Preferably, in the preparation method, the gasification mixture flows through a dehydrogenation reactor filled with an iron-based catalyst to perform catalytic dehydrogenation reaction.
Preferably, in the catalytic dehydrogenation reaction stage, the space velocity of the gasification mixture is 0.5h -1 ～2.0h -1 (preferably 0.8 to 1.5 h) -1 ) The catalytic dehydrogenation reaction pressure is 10-100 Kpa.
In the present invention, after the catalytic reaction is completed, the isopropylstyrene product can be obtained based on the existing method. For example, after catalytic dehydrogenation, dehydration treatment is performed, followed by rectification treatment to obtain t-butylstyrene.
The invention also provides a system for implementing the dehydrogenation synthesis method, which comprises a preheater, a dehydrogenation reactor, an oil-water separator, a separation tower, a tertiary butyl styrene light-removal tower, a tertiary butyl styrene heavy-removal tower, an auxiliary agent recovery tower and a tertiary butyl ethylbenzene recovery tower;
the inlet of the preheater is connected with the paths of tertiary butyl ethylbenzene, auxiliary agent and water, the outlet of the preheater is connected with the inlet of a dehydrogenation reactor loaded with an iron-based catalyst, and the outlet of the dehydrogenation reactor is connected with an oil-water separator;
the oil phase outlet of the oil-water separator is connected with the inlet of the separation tower, the light matter outlet of the separation tower is connected with the inlet of the auxiliary agent recovery tower, and the outlet of the auxiliary agent recovery tower is connected with the inlet of the tert-butyl ethylbenzene recovery tower;
the heavy matter outlet of the separation tower is connected with the inlet of the tertiary butyl styrene light-removing tower, and the outlet of the tertiary butyl styrene light-removing tower is connected with the inlet of the tertiary butyl styrene heavy-removing tower.
Mixing a p-tert-butylethylbenzene raw material, an auxiliary agent and water vapor, entering a preheater, preheating, entering a dehydrogenation reactor to obtain a reaction gas containing p-tert-butylstyrene, condensing the dehydrogenation reaction gas by a condenser, condensing the p-tert-butylstyrene, reaction byproducts, unreacted p-tert-butylethylbenzene, the auxiliary agent and water into liquid in the condenser, entering an oil-water separator, and separating non-condensable gas hydrogen from the top of the oil-water separator; the dehydrogenation liquid obtained by dehydration in the oil-water separator enters a separation tower, and a polymerization inhibitor p-tert-butyl catechol is added into the separation tower at the same time, wherein the dosage is as follows: 10 to 100ppm relative to the content of p-tert-butylstyrene. And (3) sequentially feeding the crude p-tert-butylstyrene product discharged from the lower part of the separation tower into a tert-butylstyrene light component removing tower and a tert-butylstyrene heavy component removing tower to separate light components and heavy components, thereby obtaining a high-purity p-tert-butylstyrene product. The tert-butyl ethylbenzene catalytic dehydrogenation process comprises the following steps: the temperature of the preheater is 250-350 ℃, the temperature of the dehydrogenation reactor is 500-600 ℃, and the volume space velocity of the tert-butyl ethylbenzene liquid is 0.5h -1 ～2.0h -1 The mass ratio of water to tert-butylethylbenzene is 3-7, and the dehydrogenation reaction pressure is 10-100 Kpa. The light component discharged from the upper part of the separation tower sequentially passes through an auxiliary agent recovery tower and a tert-butyl ethylbenzene recovery tower to obtain recovery auxiliary agent and recovery p-tert-butyl ethylbenzene, and the recovery auxiliary agent and the recovery p-tert-butyl ethylbenzene are returned to the dehydrogenation reactor for reuse.
Advantageous effects
The invention innovatively adopts the iron-based catalyst, and combines the auxiliary agent and the combined control of temperature, thereby being capable of effectively inhibiting the byproducts such as the isopropenyl styrene in the tert-butyl ethylbenzene dehydrogenation stage, being beneficial to improving the raw material conversion rate and improving the product yield and purity.
The production process has no oxygen participation and good production safety; meanwhile, the process has the advantages of lower required temperature, higher selectivity of tert-butyl styrene, no isopropenyl styrene impurity generation in the production process, and capability of directly separating and obtaining a high-purity p-tert-butyl styrene product through vacuum rectification.
The invention designs a reasonable process flow, uses the modified iron catalyst and the auxiliary agent, under the condition, the selectivity of the p-tertiary butyl styrene is more than 94 percent, the purity is more than 97 percent, and the mass content of the generated isopropenyl styrene is less than 0.001 percent. The process has low production cost and good production safety, and can be used for industrial production of the p-tert-butyl styrene.
Drawings
FIG. 1 is a process flow diagram of the present invention:
in the figure: 1-a preheater; a 2-dehydrogenation reactor; 3-an oil-water separator; 4-a separation tower; a 5-tertiary butyl styrene light ends removal column; a 6-tertiary butyl styrene heavy removal tower; 7-an auxiliary agent recovery tower; 8-tert-butyl ethylbenzene recovery tower
Detailed Description
Mixing and heating the p-tert-butylethylbenzene raw material and the auxiliary agent in a certain proportion with water vapor through a preheater 1 (the temperature is used for gasifying the raw material, for example, 250-350 ℃) and then entering a dehydrogenation reactor 2 for dehydrogenation reaction; condensing the dehydrogenation product and raw materials, then entering an oil-water separator 3, and allowing dehydrogenation liquid obtained by dehydration in the oil-water separator to enter a separation tower 4; the crude product of the tertiary butyl styrene discharged from the lower part of the separation tower 4 sequentially enters a tertiary butyl styrene light component removing tower 5 and a tertiary butyl styrene heavy component removing tower 6 to separate light components and heavy components, so that 97 percent of para-tertiary butyl styrene is obtained.
The light components discharged from the upper part of the separation tower 4 are sequentially subjected to an auxiliary agent recovery tower 7 and a tert-butylethylbenzene recovery tower 8 to obtain recovery auxiliary agents and recovery tert-butylethylbenzene, and the recovery auxiliary agents and the recovery tert-butylethylbenzene are returned to the dehydrogenation reactor 2 for reuse.
The invention will be further illustrated with reference to specific examples, but the invention is not limited thereto.
In the following cases, the water-oil mass ratio refers to the weight ratio of water to p-tert-butylethylbenzene.
Example 1
Preparation of a catalyst for dehydrogenation of p-tert-butylethylbenzene:
75 parts of Fe are prepared 2 O 3 5 parts of K 2 O, 6 parts of Ce 2 O 3 4 parts of MoO 3 5 parts of CaO and 5 parts of MgO are mechanically mixed and then extruded for molding.
Preheating and gasifying p-tert-butylethylbenzene, water and auxiliary agent in a preheater, entering a tubular reactor 2 for catalytic dehydrogenation reaction, and loading the reactor with the diameter of 25mmThe height of the catalyst bed is 1.5m, both ends of the catalyst in the reactor are filled with quartz sand, the mass ratio of the p-tert-butylethylbenzene raw material to the auxiliary agent cyclohexylethane is 3:1, the reaction temperature is 550 ℃, the mass ratio of water to oil is 3:1, and the space velocity is 0.8h -1 The reaction pressure was 100Kpa. The tert-butylethylbenzene dehydrogenation reaction was carried out under the above conditions. The dehydrogenation product composition is analyzed by on-line gas chromatography, the selectivity of the tert-butylstyrene is 95.32%, and the mass content of the isopropenylstyrene is less than 0.001%. After the condensation of the crude reaction product is drained through an oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 97.8% of p-tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.
Example 2
Preparation of a catalyst for dehydrogenation of p-tert-butylethylbenzene:
70 parts of Fe are prepared 2 O 3 8 parts of K 2 O, 10 parts of Ce 2 O 3 5 parts of MoO 3 4 parts of CaO and 3 parts of MgO are mechanically mixed and then extruded for molding.
Preheating and gasifying p-tert-butylethylbenzene, water and an auxiliary agent in a preheater, entering a tubular reactor 2 for catalytic dehydrogenation reaction, loading a modified iron-based catalyst in a phi 25mm reactor, wherein the height of a catalyst bed is 1.5m, filling quartz sand at two ends of the catalyst in the reactor, wherein the mass ratio of a tert-butylethylbenzene raw material to the auxiliary agent cyclohexylethane is 1:1, the reaction temperature is 580 ℃, the mass ratio of water to oil is 6:1, and the space velocity is 1.5h -1 The reaction pressure was 50Kpa. The tert-butylethylbenzene dehydrogenation reaction was carried out under the above conditions. The dehydrogenation product composition is analyzed by on-line gas chromatography, the selectivity of the tert-butylstyrene is 94.65%, and the mass content of the isopropenylstyrene is less than 0.001%. After the condensation of the crude reaction product is drained through an oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 97.5% of p-tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.
Example 3
Preparation of a catalyst for dehydrogenation of p-tert-butylethylbenzene:
75 parts of Fe are prepared 2 O 3 9 parts of K 2 O, 8 parts of Ce 2 O 3 2 parts of MoO 3 And mechanically mixing 3 parts of CaO and 3 parts of MgO, and then extruding and forming.
Preheating and gasifying p-tert-butylethylbenzene, water and an auxiliary agent in a preheater, entering a tubular reactor 2 for catalytic dehydrogenation reaction, loading a modified iron-based catalyst in a phi 25mm reactor, wherein the height of a catalyst bed is 1.5m, filling quartz sand at two ends of the catalyst in the reactor, wherein the mass ratio of a tert-butylethylbenzene raw material to the auxiliary agent cyclohexylethane is 1:1, the reaction temperature is 500 ℃, the mass ratio of water to oil is 7:1, and the space velocity is 1.0h -1 The reaction pressure was 10Kpa. The tert-butylethylbenzene dehydrogenation reaction was carried out under the above conditions. The dehydrogenation product composition is analyzed by on-line gas chromatography, the selectivity of the tert-butylstyrene is 97.32%, and the mass content of the isopropenylstyrene is less than 0.001%. After the condensation of the crude reaction product is drained through an oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 98.0% of p-tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.
Example 4
Preparation of a catalyst for dehydrogenation of p-tert-butylethylbenzene:
70 parts of Fe are prepared 2 O 3 5 parts of K 2 O, 10 parts of Ce 2 O 3 5 parts of MoO 3 5 parts of CaO and 5 parts of MgO are mechanically mixed and then extruded for molding.
Preheating and gasifying p-tert-butylethylbenzene, water and an auxiliary agent in a preheater, entering a tubular reactor 2 for catalytic dehydrogenation reaction, loading a modified iron-based catalyst in a phi 25mm reactor, wherein the height of a catalyst bed is 1.5m, filling quartz sand at two ends of the catalyst in the reactor, wherein the mass ratio of a tert-butylethylbenzene raw material to the auxiliary agent cyclohexane is 2:1, the reaction temperature is 550 ℃, the mass ratio of water to oil is 6:1, and the space velocity is 0.8h -1 The reaction pressure was 50Kpa. The tert-butylethylbenzene dehydrogenation reaction was carried out under the above conditions. By in-line gas phaseThe composition of the dehydrogenation product is analyzed by chromatography, the selectivity of the tert-butylstyrene is 97.58 percent, and the mass content of the isopropenylstyrene is less than 0.001 percent. After condensation of the crude reaction product and drainage of the oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 98.2% of p-tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.
Example 5
Preparation of a catalyst for dehydrogenation of p-tert-butylethylbenzene:
75 parts of Fe are prepared 2 O 3 5 parts of K 2 O, 6 parts of Ce 2 O 3 4 parts of MoO 3 5 parts of CaO and 5 parts of MgO are mechanically mixed and then extruded to form.
Preheating and gasifying p-tert-butylethylbenzene, water and an auxiliary agent in a preheater, entering a tubular reactor 2 for catalytic dehydrogenation reaction, loading a modified iron-based catalyst in a phi 25mm reactor, wherein the height of a catalyst bed is 1.5m, filling quartz sand at two ends of the catalyst in the reactor, wherein the mass ratio of a tert-butylethylbenzene raw material to the auxiliary agent methylcyclohexane is 4:1, the reaction temperature is 580 ℃, the mass ratio of water to oil is 4:1, and the space velocity is 0.8h -1 The reaction pressure was 100Kpa. The tert-butylethylbenzene dehydrogenation reaction was carried out under the above conditions. The dehydrogenation product composition is analyzed by on-line gas chromatography, the selectivity of the tert-butylstyrene is 96.98%, and the mass content of the isopropenylstyrene is less than 0.001%. After the condensation of the crude reaction product is drained through an oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 97.4% of tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.
Example 6
Preparation of a catalyst for dehydrogenation of p-tert-butylethylbenzene:
70 parts of Fe are prepared 2 O 3 8 parts of K 2 O, 10 parts of Ce 2 O 3 5 parts of MoO 3 4 parts of CaO and 3 parts of MgO are mechanically mixed and then extruded for molding.
P-tert-butylethaneBenzene, water and auxiliary agent are preheated and gasified in a preheater, and enter a tubular reactor 2 for catalytic dehydrogenation reaction, a modified iron catalyst is filled in the reactor with the diameter of 25mm, the height of a catalyst bed is 1.5m, both ends of the catalyst in the reactor are filled with quartz sand, the mass ratio of tert-butylethylbenzene raw material to mixed solution of auxiliary agent methylcyclohexane and cyclohexane is 3:1, the reaction temperature is 550 ℃, the water-oil mass ratio is 6:1, and the space velocity is 1.5h -1 The reaction pressure was 100Kpa. The tert-butylethylbenzene dehydrogenation reaction was carried out under the above conditions. The dehydrogenation product composition is analyzed by on-line gas chromatography, the selectivity of the tert-butylstyrene is 94.98%, and the mass content of the isopropenylstyrene is less than 0.001%. After the condensation of the crude reaction product is drained through an oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 97.3% of p-tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.
Comparative example 1
The other conditions were the same as in example 1, except that no auxiliary was added to the raw materials.
Under this condition, the selectivity of t-butylstyrene was 83.34% and the isopropenylstyrene content was 0.012%. After condensation of the crude reaction product and drainage of the oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 95.4% of p-tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.
Comparative example 2
Other conditions were the same as in comparative example 1 except that the reaction temperature was 620 ℃. Under this condition, the selectivity of t-butylstyrene was 93.28% and the isopropenylstyrene content was 1.256%. After the condensation of the crude reaction product is drained through an oil-water separator 3, the oil phase enters a separation tower 4, the crude tert-butylstyrene product discharged from the lower part of the separation tower 4 sequentially enters a tert-butylstyrene light-removing tower 5 and a tert-butylstyrene heavy-removing tower 6, and 94.8% of p-tert-butylstyrene is obtained at the top of the tert-butylstyrene heavy-removing tower 6.

Claims (10)

1. A dehydrogenation synthetic method of tert-butyl styrene is characterized in that a mixed system containing tert-butyl ethylbenzene, an auxiliary agent, water and an iron-based catalyst is subjected to catalytic dehydrogenation reaction at the temperature of 500-600 ℃, and then separated to obtain tert-butyl styrene;
the auxiliary agent is at least one of cyclohexane, cyclohexyl ethane and methylcyclohexane.
2. The method for the dehydrogenation synthesis of tert-butylstyrene according to claim 1, wherein the tert-butylethylbenzene is at least one of p-tert-butylethylbenzene and m-tert-butylethylbenzene.
3. The method for dehydrogenating and synthesizing tert-butylstyrene according to claim 1, wherein the weight ratio of tert-butylethylbenzene, auxiliary agent and water is 1-4: 1:3 to 7.
4. The method for dehydrogenating t-butylstyrene according to claim 1, wherein the iron-based catalyst comprises Fe 2 O 3 、K 2 O、Ce 2 O 3 、MoO 3 CaO and MgO.
5. The method for dehydrogenating t-butylstyrene according to claim 4, wherein the iron-based catalyst comprises K in weight percent 2 O 4～9％；Ce 2 O 3 6～11％；MoO 3 1 to 5 percent; 0.5 to 5 percent of CaO; mgO 0.5-5%; the balance of Fe 2 O 3 。
6. The method for the dehydrogenation synthesis of tert-butylstyrene according to any one of claims 1 to 5, wherein tert-butylethylbenzene, auxiliary agent and water are preheated and gasified in advance, and then the gasified mixture is contacted with an iron-based catalyst to perform catalytic dehydrogenation reaction at said temperature.
7. The method for the dehydrogenation synthesis of t-butylstyrene according to claim 6, wherein the gasifying mixture is passed through a dehydrogenation reactor filled with an iron-based catalyst to perform catalytic dehydrogenation.
8. The process for the dehydrogenation-to-synthesis of tert-butylstyrene according to claim 6, wherein the space velocity of the gasification mixture is 0.5h during the catalytic dehydrogenation reaction -1 ～2.0h -1 The catalytic dehydrogenation reaction pressure is 10-100 Kpa.
9. The method for the dehydrogenation synthesis of tert-butylstyrene according to claim 1, wherein the tert-butylstyrene is obtained by performing dehydration treatment after catalytic dehydrogenation and then by performing rectification treatment.
10. A system for carrying out the dehydrogenation-synthesis process according to any one of claims 1 to 9, characterized by comprising a preheater, a dehydrogenation reactor, an oil-water separator, a separation column, a tertiary butyl styrene light ends removal column, a tertiary butyl styrene heavy ends removal column, an auxiliary agent recovery column, a tertiary butyl ethylbenzene recovery column;
the inlet of the preheater is connected with the paths of tertiary butyl ethylbenzene, auxiliary agent and water, the outlet of the preheater is connected with the inlet of a dehydrogenation reactor loaded with an iron-based catalyst, and the outlet of the dehydrogenation reactor is connected with an oil-water separator;
the oil phase outlet of the oil-water separator is connected with the inlet of the separation tower, the light matter outlet of the separation tower is connected with the inlet of the auxiliary agent recovery tower, and the outlet of the auxiliary agent recovery tower is connected with the inlet of the tert-butyl ethylbenzene recovery tower;
the heavy matter outlet of the separation tower is connected with the inlet of the tertiary butyl styrene light-removing tower, and the outlet of the tertiary butyl styrene light-removing tower is connected with the inlet of the tertiary butyl styrene heavy-removing tower.
CN202211012702.2A 2022-08-23 2022-08-23 Dehydrogenation synthesis method and system of tert-butylstyrene Pending CN117658761A (en)

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