A process and system for the production of pseudocumene and durene by alkylation

Abstract

The present application belongs to the technical field of aromatic hydrocarbon production, and relates to a method and system for producing trimethylbenzene and quarterphenyl by alkylation. Light aromatic hydrocarbons and methanol are used as raw materials, and alkylation is carried out under the catalysis of a modified molecular sieve catalyst and at a temperature of 250-600 DEG C. The material after alkylation is subjected to further alkylation under the catalysis of the modified molecular sieve catalyst and at a temperature of 250-600 DEG C. The modified molecular sieve catalyst is composed of a molecular sieve and a metal oxide supported in the molecular sieve, the molecular sieve is one or more of HY, Hbeta, IM-5, NU87, EU-1 and mordenite, and the metal in the metal oxide is one or more of Mg, Cu, La, Zn and Mo. The present application solves the technical problems of low content of trimethylbenzene and quarterphenyl components and difficult separation of trimethylbenzene and quarterphenyl in the industrial separation method by directly producing trimethylbenzene and quarterphenyl.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aromatic hydrocarbon production, and relates to a method and system for producing pseudocumene and quarterphenyl by alkylation. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general context of the present application and does not necessarily constitute an acknowledgement or any form of suggestion that this information forms part of the prior art already known to a person of ordinary skill in the art.

[0003] According to the research and understanding of the inventors, the most commonly used method for producing pseudocumene, quarterphenyl and the like in the industry at present is mainly a C9+ heavy aromatic hydrocarbon separation method, for example, recycling of reforming by-products. However, the content of components such as methyl ethylbenzene, trimethylbenzene, pseudotetramethylbenzene and the like in the reforming by-products is relatively high, and the boiling points of some of the components are very close. Through the separation method, the product purity is not high and the separation cost is extremely high. For another example, crude benzene and crude methanol are used as raw materials to produce p-xylene, o-xylene and pseudocumene through acid washing, hydrogenation pretreatment, alkylation reaction, rectification, crystallization separation and isomerization reaction. The production cost of p-xylene, o-xylene and pseudocumene is reduced, and the non-petroleum raw material route is realized to produce aromatic hydrocarbon products. However, the method is mainly for producing xylene, and the amount of pseudocumene is small and high-end fine quarterphenyl and the like cannot be produced. SUMMARY

[0004] In order to solve the technical problems of low content of pseudocumene and quarterphenyl components and difficult separation in the industrial separation method, the purpose of the present application is to provide a method and system for producing pseudocumene and quarterphenyl by alkylation. The present application directly produces pseudocumene and quarterphenyl to solve the above problems.

[0005] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0006] On the one hand, a method for producing pseudocumene and quarterphenyl by alkylation uses light aromatic hydrocarbons and methanol as raw materials, and performs alkylation reaction under the catalysis of a modified molecular sieve catalyst and at a temperature of 250-600℃. The material after the alkylation reaction is subjected to further alkylation reaction under the catalysis of the modified molecular sieve catalyst and at a temperature of 250-600℃.

[0007] The light aromatic hydrocarbons are one or more of benzene, toluene, o-xylene, m-xylene and p-xylene.

[0008] The modified molecular sieve catalyst is composed of a molecular sieve and a metal oxide supported in the molecular sieve, the molecular sieve is one or more of HY, Hbeta, IM-5, NU87, EU-1, mordenite, and the metal in the metal oxide is one or more of Mg, Cu, La, Zn and Mo.

[0009] The direct preparation of trimethylbenzene and tetramethylbenzene by chemical synthesis can avoid the difficulty of preparing trimethylbenzene and tetramethylbenzene by industrial separation method. In order to synthesize trimethylbenzene and tetramethylbenzene, suitable raw materials are used first, and the light aromatic hydrocarbon and methanol used in the present application are the most conventional chemical raw materials in industrial production. Secondly, a suitable catalyst is used to catalyze the alkylation reaction of light aromatic hydrocarbon and methanol to produce trimethylbenzene and tetramethylbenzene. Research shows that the modified molecular sieve catalyst provided by the present application can directly alkylate light aromatic hydrocarbon and methanol to obtain trimethylbenzene and tetramethylbenzene. Thirdly, in order to avoid the problem that the content of the target product is low in the synthesis process, the material after alkylation reaction is recycled for alkylation reaction. Research shows that the recycling of the material after alkylation reaction for alkylation reaction is not equivalent to increasing the time of alkylation reaction. Increasing the time of alkylation reaction alone is difficult to increase the yield of trimethylbenzene and tetramethylbenzene, while recycling the material after alkylation reaction for alkylation reaction can increase the yield of trimethylbenzene and tetramethylbenzene. Through the above technical solutions of the present application, the present application can directly obtain trimethylbenzene and tetramethylbenzene by chemical reaction, thereby avoiding the technical difficulties such as low content of trimethylbenzene and tetramethylbenzene components and difficult separation of trimethylbenzene and tetramethylbenzene by industrial separation method.

[0010] In another aspect, a system for producing trimethylbenzene and tetramethylbenzene by alkylation is used to implement the above method, comprising:

[0011] A light aromatic hydrocarbon source is used to transport light aromatic hydrocarbon to the reactor;

[0012] A methanol source is used to transport methanol to the reactor;

[0013] A reactor is used for alkylation reaction of light aromatic hydrocarbon and methanol to produce trimethylbenzene and tetramethylbenzene;

[0014] A product material recycling pipeline is used to transport the material after alkylation reaction discharged from the reactor back to the reactor;

[0015] An online detection device is installed on the product material recycling pipeline to monitor trimethylbenzene and tetramethylbenzene in the product material recycling pipeline;

[0016] A product side sampling pipeline is connected with the product material recycling pipeline to sample trimethylbenzene and tetramethylbenzene meeting the standard according to the detection result of the online detection device.

[0017] The present application has the following advantages:

[0018] 1. The present application realizes the production of trimethylbenzene and quarterphenyl products by using the light aromatic hydrocarbon alkylation method, and can realize the high content control of target products, and the product has less by-products.

[0019] 2. The present application catalyzes the alkylation reaction of light aromatic hydrocarbon and methanol by using a modified molecular sieve catalyst, and realizes the increase of the selectivity and yield of trimethylbenzene and quarterphenyl through the shape-selective catalysis of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0020] The drawings constituting a part of the specification of the present application serve to provide further understanding of the present application, and the illustrative embodiments of the present application and the description thereof serve to explain the present application, and do not constitute improper limitations on the present application.

[0021] Figure 1 It is a structural schematic diagram of the system for producing trimethylbenzene and quarterphenyl by alkylation in the embodiments of the present application.

[0022] 1, light aromatic hydrocarbon raw material tank; 2, methanol tank; 3, light aromatic hydrocarbon feed pump; 4, methanol feed pump; 5, mixer; 6, preheater; 7, fixed bed reactor; 8, cooler; 9, three-phase separator; 10, oil phase reflux pump; 11, online chromatograph; 51, reflux stop valve; 52, first methanol stop valve; 53, second methanol stop valve; 71, first methanol segmented feed stop valve; 72, second methanol segmented feed stop valve; 73, third methanol segmented feed stop valve; 74, first methanol segmented feed flowmeter; 75, second methanol segmented feed flowmeter; 76, third methanol segmented feed flowmeter; 111, oil phase reflux valve; 112, oil phase outlet valve;

[0023] Figure 2 It is an infrared spectrum of the La / HY catalyst prepared in the embodiments of the present application. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0025] It should be noted that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, they mean the presence of a feature, step, operation, device, component and / or combination thereof.

[0026] In view of the problems of low content of m-xylene and durene components and difficult separation in the existing industrial separation method for producing m-xylene and durene, the application provides a method and system for producing m-xylene and durene by alkylation.

[0027] In a typical embodiment of the application, a method for producing m-xylene and durene by alkylation is provided, which uses light aromatic hydrocarbon and methanol as raw materials, and performs alkylation under the catalysis of a modified molecular sieve catalyst and at a temperature of 250-600 ℃; the material after the alkylation is continuously subjected to alkylation under the catalysis of the modified molecular sieve catalyst and at a temperature of 250-600 ℃.

[0028] In the application, the light aromatic hydrocarbon is one or more of benzene, toluene, o-xylene, m-xylene and p-xylene.

[0029] The modified molecular sieve catalyst is composed of a molecular sieve and a metal oxide supported in the molecular sieve, the molecular sieve is one or more of HY, Hβ, IM-5, NU87, EU-1 and mordenite, and the metal in the metal oxide is one or more of Mg, Cu, La, Zn and Mo.

[0030] In some embodiments, the modified molecular sieve catalyst is prepared by using a saturated impregnation method to saturate a metal salt aqueous solution into the molecular sieve, and drying and calcining the saturated molecular sieve to obtain the modified molecular sieve catalyst. More specifically, in the saturated impregnation method, the saturated water absorption rate of the molecular sieve is first obtained, and then a metal salt aqueous solution with a specific concentration is prepared according to the saturated water absorption rate, and then the molecular sieve is saturated with the metal salt aqueous solution, so that a modified molecular sieve catalyst with a specific metal loading amount can be obtained. The drying temperature is 100-200 ℃. The drying time is 3-5 h. The calcination temperature is 450-550 ℃. The calcination time is 2-6 h.

[0031] In some embodiments, the molecular sieve is HY, and the metal in the metal oxide is La; or the molecular sieve is Hβ, and the metal in the metal oxide is Zn. Research shows that the catalyst has higher raw material conversion rate and higher selectivity of m-xylene and durene, and when the molecular sieve is HY and the metal in the metal oxide is La, the selectivity of m-xylene and durene is the highest.

[0032] In some embodiments, the light aromatic hydrocarbon is one or more of toluene, o-xylene, m-xylene and p-xylene. Under this condition, it is more conducive to produce m-xylene and durene.

[0033] In some embodiments, the molar ratio of the light aromatic hydrocarbon to methanol is 1:5-5:1.

[0034] In some embodiments, the pressure of the alkylation reaction is 0.5-2 MPa.

[0035] In some embodiments, the total mass space velocity of the raw material liquid is 0.5-5 h -1 .

[0036] In some embodiments, the oil phase material and the gas phase material after the alkylation reaction are subjected to further alkylation reaction under the catalysis of the modified molecular sieve catalyst and at a temperature of 250-600°C. The obtained water phase material is discharged.

[0037] In some embodiments, methanol is supplemented during the alkylation reaction. Studies have shown that methanol itself is prone to reaction under the catalysis of the catalyst to generate dimethyl ether, propane, butane and other alkanes. Therefore, when the light aromatic hydrocarbon and methanol mixed solution is fed, the methanol is rapidly reacted in a very short time after entering the reactor, and the light aromatic hydrocarbon has not been completely converted. Therefore, methanol needs to be supplemented during the reaction.

[0038] Another embodiment of the present application provides a system for producing pseudocumene and quarterphenyl through alkylation, which is used to implement the above method, and comprises:

[0039] A light aromatic hydrocarbon source for feeding light aromatic hydrocarbon into the reactor;

[0040] A methanol source for feeding methanol into the reactor;

[0041] A reactor for producing pseudocumene and quarterphenyl through alkylation of light aromatic hydrocarbon and methanol;

[0042] A product material circulation pipeline for feeding the material discharged from the reactor after the alkylation reaction back to the reactor;

[0043] An online detection device installed on the product material circulation pipeline for monitoring the pseudocumene and quarterphenyl in the product material circulation pipeline;

[0044] A product side sampling pipeline connected with the product material circulation pipeline for sampling the pseudocumene and quarterphenyl meeting the standards according to the detection result of the online detection device.

[0045] In some embodiments, the reactor is a fixed bed reactor.

[0046] In some embodiments, the reactor is provided with a plurality of methanol feeding ports. The multiple-stage side-line feeding of methanol through the plurality of methanol feeding ports not only supplements the methanol, but also controls the amount of methanol added into the reactor at the beginning, thereby avoiding the side reaction of methanol itself, making the methanol react more with the light aromatic hydrocarbon, increasing the content of the product, and reducing the content of the byproduct.

[0047] In one or more embodiments, a mixer is included, the outlet of the light aromatic hydrocarbon source is connected to the mixer, the outlet of the methanol source is connected to several methanol feeding ports, and the outlet of the mixer is connected to the mixing material inlet of the reactor. This arrangement facilitates the pre-mixing of the light aromatic hydrocarbon and the methanol, and improves the contact between the light aromatic hydrocarbon and the methanol.

[0048] In one or more embodiments, a preheater is included, and the outlet of the mixer is connected to the preheater, and the outlet of the preheater is connected to the mixing material inlet of the reactor. This arrangement enables the preheating of the mixture of the light aromatic hydrocarbon and the methanol, and in continuous production, avoids the direct addition of the mixture of the light aromatic hydrocarbon and the methanol into the reactor, thereby improving the stability of the continuous production.

[0049] In some embodiments, a cooler and a three-phase separator are included, the product material circulation pipeline includes a gas phase circulation pipeline and an oil phase circulation pipeline, the material outlet of the reactor is connected to the cooler and the three-phase separator in sequence, the gas phase outlet of the three-phase separator is connected to the gas phase circulation pipeline, and the oil phase outlet of the three-phase separator is connected to the oil phase circulation pipeline.

[0050] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with specific examples and comparative examples.

[0051] In the following examples, the preparation method of the modified molecular sieve catalyst is as follows:

[0052] (1) Test the saturated water absorption rate of HY, Hβ, IM-5, NU87, EU-1, and mordenite.

[0053] (2) Weigh 300g of molecular sieve (carrier), calculate the water absorption amount, and dissolve one or several metal nitrates such as Mg, Cu, La, Zn, and Mo into water corresponding to the water absorption amount.

[0054] (3) Use the saturated immersion method to immerse the corresponding nitrate solution into the corresponding molecular sieve, and place it at room temperature for 2h.

[0055] (4) Dry the molecular sieve obtained in step (3) at 150℃ for 4h, and program the temperature to 550℃ for calcination for 2h.

[0056] (5) After the calcined modified molecular sieve catalyst is pressed and sieved, 5-10 mesh modified molecular sieve catalyst particles are prepared.

[0057] The composition of the obtained modified molecular sieve catalyst is shown in Table 1.

[0058] Table 1 Modified molecular sieve catalyst and loading amount

[0059]

[0060]

[0061] The infrared spectrum of the La / HY catalyst is shown in Fig. 1. Figure 2

[0062] The system structure for synthesizing m- xylene and p- xylene by toluene and methanol alkylation reaction in the following example is shown in Fig. 2, which comprises a light aromatic hydrocarbon raw material tank 1, a methanol tank 2, a light aromatic hydrocarbon feed pump 3, a methanol feed pump 4, a mixer 5, a preheater 6, a fixed bed reactor 7, a cooler 8, a three-phase separator 9, an oil phase reflux pump 10, and an online chromatograph 11. Figure 1

[0063] The fixed bed reactor 7 is fixed with the modified molecular sieve catalyst particles described above. The fixed bed reactor 7 is provided with three-stage methanol side-line feed ports.

[0064] The outlet of the light aromatic hydrocarbon raw material tank 1 is connected to the light aromatic hydrocarbon feed pump 3 and the mixer 5 in sequence. The outlet of the methanol tank 2 is connected to the methanol feed pump 4. The outlet of the methanol feed pump 4 is connected to the mixer 5 and the three-stage methanol side-line feed ports of the fixed bed reactor 7. The outlet of the mixer 5 is connected to the preheater 6. The outlet of the preheater 6 is connected to the mixed material inlet at the top of the fixed bed reactor 7. The outlet at the bottom of the fixed bed reactor 7 is connected to the cooler 8 and the three-phase separator 9 in sequence. The gas phase outlet of the three-phase separator 9 is connected to the preheater 6. The oil phase outlet of the three-phase separator 9 is connected to the oil phase reflux pump 10, the online chromatograph 11, and the mixer 5 in sequence.

[0065] A first methanol stop valve 52 is installed in the pipeline connecting the outlet of the methanol feed pump 4 to the mixer 5. A methanol side-supplement pipeline is connected between the pipeline between the outlet of the methanol feed pump 4 and the first methanol stop valve 52 and the three-stage methanol side-line feed ports of the fixed bed reactor 7, which comprises a methanol side-supplement main pipeline and three methanol side-supplement branch pipelines. The methanol side-supplement main pipeline is provided with a second methanol stop valve 53. The three methanol side-supplement branch pipelines are provided with a first methanol segmented feed stop valve 71, a second methanol segmented feed stop valve 72, a third methanol segmented feed stop valve 73, a first methanol segmented feed flow meter 74, a second methanol segmented feed flow meter 75, and a third methanol segmented feed flow meter 76.

[0066] An oil phase reflux valve 111 and a reflux stop valve 51 are installed in the oil phase circulation pipeline between the online chromatograph 11 and the mixer 5. An oil phase reflux pump 10 and an oil phase circulation pipeline between the online chromatograph 11 are provided with a product side sampling pipeline, which is provided with an oil phase outlet valve 112.

[0067] Example 1

[0068] The above system is used to synthesize m- xylene and p- xylene by fixed bed continuous reaction.

[0069] ​​Reaction conditions: temperature 400℃, liquid mass space velocity 1h -1 , toluene:methanol (mole ratio) = 1:3, reaction time 4 hours, methanol side-line feed valve closed, oil phase reflux valve closed, and all products were collected. The reaction results of different catalysts are shown in Table 2.

[0070] Table 2 Reaction results of different catalysts

[0071]

[0072]

[0073] Table 2 shows that the above modified molecular sieve catalysts can catalyze the alkylation reaction of toluene and methanol to obtain pseudotri-methylbenzene and sym-tetramethylbenzene. Among them, the catalytic effect of Zn / Hβ and La / HY is better than that of other catalysts; the catalytic effect of La / HY is more significant than that of Zn / Hβ.

[0074] Example 2

[0075] The above system is used to perform fixed-bed continuous reaction to synthesize pseudotri-methylbenzene and sym-tetramethylbenzene.

[0076] The catalyst is La / HY. Reaction conditions: temperature 400℃, liquid mass space velocity 1h -1 , p-xylene:methanol (mole ratio) = 1:2, reaction time 4 hours, methanol side-line feed valve closed, oil phase reflux valve closed, and all products were collected. The reaction results are shown in Table 3.

[0077] Table 3 Reaction results

[0078]

[0079] Table 3 and Table 2 show that both p-xylene and toluene can realize the production of pseudotri-methylbenzene and sym-tetramethylbenzene. When the raw material is p-xylene, it is more conducive to the production of pseudotri-methylbenzene and sym-tetramethylbenzene.

[0080] Example 3

[0081] The above system is used to perform fixed-bed continuous reaction to synthesize pseudotri-methylbenzene and sym-tetramethylbenzene.

[0082] Reaction conditions: temperature 350-450℃, liquid mass space velocity 0.5-1h -1 , toluene:methanol (mole ratio) = 1:3, reaction time 2 hours, methanol side-line feed valve closed, oil phase reflux valve closed, and all products were collected. The reaction results are shown in Table 4.

[0083] Table 4 Reaction results of different reaction temperatures and mass space velocities

[0084]

[0085] Table 4 shows that when the reaction temperature is 400℃, the mass space velocity is 0.5h -1 -1, the molar ratio of toluene to methanol in the mixer is 1:2, the methanol side feed valve is opened, the molar ratio of the side feed methanol to toluene is 1:1, the oil phase reflux valve is closed, and the reaction time is 4 hours, the conversion of toluene, the selectivity of meta-xylene and the selectivity of tetramethylbenzene are all better.

[0086] Example 4

[0087] The above system is used to synthesize meta-xylene and tetramethylbenzene in a fixed bed continuous reaction.

[0088] The reaction conditions are: the temperature is 400℃, the liquid mass space velocity is 0.25h -1 -1 and 0.5h-1 respectively, the molar ratio of toluene to methanol in the mixer is 1:2, the methanol side feed valve is opened, the molar ratio of the side feed methanol to toluene is 1:1, the reaction time is 4 hours and 2 hours respectively, the oil phase reflux valve is closed, and all the products are collected. The reaction results are shown in Table 5.

[0089] Table 5 Reaction results under the condition of side feed

[0090]

[0091] Table 5 shows that under the condition of side feed, the mass space velocity is reduced, the reaction time is increased, the conversion of toluene is improved, and the selectivity of meta-xylene and tetramethylbenzene is decreased. The main reason is that the contact time of the raw material and the catalyst is longer, which causes the increase of side reactions.

[0092] Example 5

[0093] The above system is used to synthesize meta-xylene and tetramethylbenzene in a fixed bed continuous reaction.

[0094] The reaction conditions are: the temperature is 400℃, the liquid mass space velocity is 0.5h -1 -1, the molar ratio of toluene to methanol in the mixer is 1:2, the reaction time is 2 hours, the methanol side feed valve is opened, the molar ratio of the side feed methanol to toluene is 1:1, the oil phase reflux valve is opened, and the products are not collected for one cycle. The reaction results are shown in Table 6.

[0095] Table 6 Reaction results of side feed and product one cycle

[0096]

[0097] As can be seen from the comparison of Table 5 and Table 6, under the same mass space velocity condition (0.5h -1)Under the catalytic process of recycling reaction products, the selectivity of the reaction products of the methylbenzene to the methylbenzene and the methylbenzene is higher, and the specific analysis reason is that the reaction product and the catalyst are contacted for a short time under the process condition, and the methylbenzene conversion rate and the selectivity of the reaction products of the methylbenzene to the methylbenzene and the methylbenzene are continuously improved by twice contact with the catalyst.

[0098] The preferred embodiments of the present application have been described above, but the present application is not limited to the above, and various modifications and changes can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the production of pseudocumene and durene by alkylation, characterized in that, The light aromatic hydrocarbon and the methanol are used as raw materials, and the alkylation reaction is carried out under the catalysis of a modified molecular sieve catalyst and at a temperature of 250-600 ℃; the material after the alkylation reaction is continuously subjected to the alkylation reaction under the catalysis of the modified molecular sieve catalyst and at a temperature of 250-600 ℃; The modified molecular sieve catalyst is composed of a molecular sieve and a metal oxide supported in the molecular sieve, the molecular sieve is HY, and the metal in the metal oxide is La; or, the molecular sieve is Hβ, and the metal in the metal oxide is Zn. The preparation method of the modified molecular sieve catalyst comprises the following steps: saturating a metal salt aqueous solution into the molecular sieve by using a saturation impregnation method, and drying and calcining the saturated molecular sieve to obtain the modified molecular sieve catalyst; in the saturation impregnation method, the saturated water absorption rate of the molecular sieve is first obtained, then a metal salt aqueous solution with a specific concentration is prepared according to the saturated water absorption rate, and then the molecular sieve is saturated with the metal salt aqueous solution, so that the modified molecular sieve catalyst with a specific metal loading amount can be obtained; the drying temperature is 100-200 ℃; the drying time is 3-5 h; the calcination temperature is 450-550 ℃; and the calcination time is 2-6 h. The light aromatic hydrocarbon is one or both of toluene and p-xylene.

2. The process for the production of pseudocumene and durene by alkylation according to claim 1, characterized in that, The molar ratio of the light aromatic hydrocarbon to the methanol is 1:5-5:

1. or, total mass space velocity of the raw material liquid 0.5 to 5 h -1 .

3. The process for the production of pseudocumene and durene by alkylation according to claim 1, characterized in that, The oil phase material and the gas phase material after the alkylation reaction are continuously subjected to the alkylation reaction under the catalysis of the modified molecular sieve catalyst and at a temperature of 250-600 ℃. Or, the methanol is supplemented during the alkylation reaction.

4. The process for the production of pseudocumene and durene by alkylation according to claim 1, characterized in that, A system for realizing the method for producing trimethylbenzene and quadricyclane by alkylation according to claim 1, comprising: a light aromatic hydrocarbon source for delivering light aromatic hydrocarbon to a reactor; a methanol source for delivering methanol to the reactor; the reactor for alkylation of the light aromatic hydrocarbon and the methanol to produce trimethylbenzene and quadricyclane; a product material circulation pipeline for delivering the material after the alkylation reaction in the reactor back to the reactor; an online detection device installed on the product material circulation pipeline for monitoring trimethylbenzene and quadricyclane in the product material circulation pipeline; a product side extraction pipeline connected with the product material circulation pipeline for extracting trimethylbenzene and quadricyclane meeting the standards according to the detection result of the online detection device.

5. The process for the production of pseudocumene and durene by alkylation according to claim 4, characterized in that, The reactor is a fixed bed reactor.

6. The process for the production of pseudocumene and durene by alkylation according to claim 4, characterized in that, The reactor is provided with a plurality of methanol feeding ports.

7. The process for the production of pseudocumene and durene by alkylation according to claim 4, characterized in that, The system comprises a mixer, the outlet of the light aromatic hydrocarbon source is connected with the mixer, the outlet of the methanol source is connected with the plurality of methanol feeding ports, and the outlet of the mixer is connected with the mixed material inlet of the reactor.

8. The process for the production of pseudocumene and durene by alkylation according to claim 7, characterized in that, The system comprises a preheater, which is arranged between the outlet of the mixer and the mixed material inlet of the reactor.

9. The process for the production of pseudocumene and durene by alkylation according to claim 4, characterized in that, The system comprises a cooler and a three-phase separator, the product material circulation pipeline comprises a gas phase circulation pipeline and an oil phase circulation pipeline, the material outlet of the reactor is connected with the cooler and the three-phase separator in sequence, the gas phase outlet of the three-phase separator is connected with the gas phase circulation pipeline, and the oil phase outlet of the three-phase separator is connected with the oil phase circulation pipeline.

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