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Method for preparing fluidized bed of para-xylene by aromatics alkylation

A technology for the alkylation of aromatic hydrocarbons and p-xylene, which is applied in the field of fluidized beds, and can solve problems such as poor catalyst stability, many side reactions of alkylating reagents, and large temperature rise of the reaction bed.

Active Publication Date: 2012-03-14
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] The present invention aims to solve the problems in the prior art that the raw material is single, the temperature rise of the reaction bed is large, the stability of the catalyst is poor, the side reactions of the alkylation reagent are many and the utilization rate is low, and a new aromatic hydrocarbon alkylation system is provided. Fluidized bed process for toluene

Method used

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  • Method for preparing fluidized bed of para-xylene by aromatics alkylation

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Effect test

Embodiment 1～3

[0034] The alkylation reaction was carried out according to the steps and conditions described in Comparative Example 1, wherein the aromatic hydrocarbon raw material was a mixture of benzene and toluene in different proportions, and the specific proportions and reaction evaluation results were listed in Table 1 for comparison.

[0035] Table 1

[0036]

[0037] The data in Table 1 shows that the use of benzene and toluene as mixed aromatics feed has no effect on the control of the temperature rise of the catalyst bed, but the side reactions of methanol itself and the deep alkylation reaction are still significantly suppressed, and the methyl utilization rate The selectivity of p-xylene and xylene was significantly improved, and the selectivity of p-xylene was slightly improved, while the conversion rate of aromatics decreased to a certain extent.

Embodiment 4～7

[0039] Carry out the alkylation reaction according to the steps and conditions described in Example 2, wherein the alkylation reagent feed is selected from a mixture of methanol and dimethyl ether, and the molar percentage of the methyl group contained in the dimethyl ether in the alkylation reagent is changed, specifically The ratio and reaction evaluation results are listed in Table 2 for comparison.

[0040] Table 2

[0041]

[0042] The data in Table 2 show that as the content of dimethyl ether in the alkylating agent increases, the exothermic heat of the reaction and the temperature rise of the catalyst bed show a downward trend, thereby inhibiting the side reactions of the alkylating agent itself, the deep alkylation reaction and the heterogeneous reaction. structuring reaction.

Embodiment 8～11

[0044] The alkylation reaction was carried out according to the steps and conditions described in Example 7, and the molar ratio of methyl groups and aromatic hydrocarbons contained in the alkylating agent in the feed was changed. The specific ratios and reaction evaluation results are listed in Table 3 for comparison.

[0045] table 3

[0046]

[0047] The data in Table 3 shows that the amount of alkylating agent has a great influence on various performance indicators. The larger the amount of alkylating agent is, the higher the conversion rate of aromatics is, but the worse the product selectivity and methyl utilization rate are.

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Abstract

The invention relates to a method preparing a fluidized bed of para-xylene by aromatics alkylation, which mainly solves the problems of single raw material, large temperature increase of a reaction bed layer, poor catalyst stability, frequent side reaction of an alkylation reagent and low utilization rate in the prior art. According to the invention, the method comprises the following steps: mixing and vaporizing benzene and toluene feed to obtain an aromatic mixture I, vaporizing a mixture of methanol or methanol and dimethyl ether to obtain an alkylation reagent feed II; merging 10-90% of alkylation reagent feed II, the aromatic mixture I and hydrogen carrying gas to obtain a reaction mixture III; the rest part of the alkylation reagent feed II forms single stream or a plurality of streams and can be introduced into a reactor from one position or a plurality of positions of the inlet downstream of a fluidized bed reactor. The technical problem better solves the problems, and can be used in the industrial production for preparing para-xylene by aromatics alkylation.

Description

technical field [0001] The invention relates to a fluidized bed method for preparing p-xylene by alkylation of toluene. Background technique [0002] P-xylene is an important organic chemical raw material. Its main purpose is to synthesize terephthalic acid through oxidation, and then conduct polycondensation reaction with ethylene glycol to produce polymer materials polyethylene terephthalate (polyester), polyester It is a polyester material with excellent performance and great demand, which is widely used in the fields of textile and packaging materials. [0003] At present, the most commonly used p-xylene production method in industry is disproportionation of toluene and transalkylation of C-nine aromatic hydrocarbons. Due to the limitation of thermodynamic equilibrium, the C-eight aromatic hydrocarbon products obtained by this method usually only contain about 24% p-xylene, while Demand for xylene The demand for p-xylene in the market accounts for more than 60%, so this...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C2/88B01J8/32
Inventor 孔德金夏建超邹薇李辉
Owner CHINA PETROLEUM & CHEM CORP
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