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Fluidized catalytic method for toluene methylation

A technology of toluene methylation and fluidized catalysis is applied in the field of fluidized catalysis of toluene methylation, and can solve the problems of low utilization rate of methanol, many side reactions, large temperature rise of catalyst bed and the like

Inactive 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

[0012] What the present invention is to solve is the problem of large temperature rise of the catalyst bed, many side reactions and low utilization rate of methanol in the prior art, and provides a new fluidized catalytic method for toluene methylation

Method used

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  • Fluidized catalytic method for toluene methylation
  • Fluidized catalytic method for toluene methylation
  • Fluidized catalytic method for toluene methylation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Alkylation reagent methanol first enters the fixed bed reactor to contact with the dehydration catalyst, the reaction conditions are: methanol feed temperature 260°C, weight space velocity 2.0h -1 , the reaction pressure is 0.5MPa, and the catalyst loading is 696 grams. The specific composition of the catalyst is shown in Table 1, and the mixed effluent I containing dimethyl ether, water and unreacted methanol is generated; the toluene raw material and the reaction effluent I are mixed and vaporized to obtain Reaction mixture II then enters a fluidized bed reactor to contact with a methylation catalyst, the reaction conditions are: catalyst loading 2000 g, feeding temperature 400 ° C, aromatics weight space velocity 4.0 h -1 , the molar ratio of methanol to aromatics is 0.5, no hydrogen is present, the reaction pressure is 0.5MPa, and the alkylation catalyst used contains 20% by weight of Al 2 o 3 modifier and 15% SiO 2 Modifier, residual weight is hydrogen type ZSM-5...

Embodiment 2～4

[0031] The methylation reaction was carried out according to the steps and conditions described in Example 1, and different methanol dehydration catalysts were selected. The specific composition of the catalysts is shown in Table 1. The reaction evaluation results are listed in Table 1 for comparison.

[0032] Table 1

[0033]

[0034] The data in Table 1 shows that the pre-dehydration of methanol, the alkylation reagent, effectively controls the exothermicity of the alkylation process and the temperature rise of the catalyst bed, making the xylene selectivity and p-xylene selectivity significantly improved, and the utilization rate of methanol It is also slightly improved, and the conversion rate of aromatics has a small change.

Embodiment 5～7

[0036] The methylation reaction was carried out according to the steps and conditions described in Example 2, wherein the loading amount of the methanol dehydration catalyst was changed to 232 grams, and the dehydration reaction conditions were changed. The specific reaction conditions and evaluation results are listed in Table 2.

[0037] Table 2

[0038]

[0039] The data in Table 2 shows that the change of the methanol dehydration process will affect the conversion of methanol, and thus affect the control effect of the temperature rise of the alkylation. The higher the methanol dehydration conversion rate, the better the reaction result.

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Abstract

The invention relates to a fluidized catalytic method for toluene methylation, and mainly solves the problems of great temperature rise of a catalyst bed, many side reactions and low methanol utilization rate in existing technologies. The method comprises the steps of: a) first putting an alkylating reagent methanol into a fixed bed reactor so as to contact with a dehydration catalyst for reaction, thus generating mixed effluent I containing dimethyl ether, water and unreacted methanol; b) mixing a toluene raw material with the reaction effluent I and conducting vaporization so as to obtain a reaction mixture II, which is then subjected to contact with a methylation for reaction catalyst in a fluidized bed reactor, thus obtaining oil-phase reaction effluent III rich in xylene, gas-phase reaction effluent IV and water-phase effluent V; c) separating the oil-phase reaction effluent III, thus obtaining an unconverted toluene fraction containing bits of benzene, a mixed C8 fraction as well as C9 and C9+ heavy aromatic fractions; d) subjecting the mixed C8 fraction to adsorption, crystallization or a adsorption / crystallization combination separation and isomerization system, thus obtaining a paraxylene product, refluxing the unconverted toluene fraction containing bits of benzene, and mixing it with the reaction mixture II in the fluidized bed reactor for conversion. The technical method of the invention well solves the above problems, and can be applied to industrial production of paraxylene preparation through a methylation reaction with toluene as the raw material.

Description

technical field [0001] The invention relates to a fluidized catalytic method for toluene methylation. 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 concentration com...

Claims

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Application Information

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IPC IPC(8): C07C15/08C07C2/86
Inventor 孔德金夏建超李经球
Owner CHINA PETROLEUM & CHEM CORP
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