Process for combined preparation of p-xylene and low carbon olefin by methylation of toluene

A technology of p-xylene and toluene methylation, applied in the field of toluene methylation to p-xylene co-production of low-carbon olefins, can solve the problems that the catalysts cannot be satisfied at the same time, and the characteristics of the catalysts are different.

Inactive Publication Date: 2006-01-18
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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Problems solved by technology

[0004] The above-mentioned patents respectively propose new ways to prepare p-xylene and low-carbon olefins. Since the two reaction processes are acid-catalyzed reactions, both require shape-selective catalysis, so both use modified HZSM-5 molecular sieves as catalysts. components, but due to

Method used

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Examples

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Effect test

Embodiment 1

[0013] ZSM-5 molecular sieve (pore size 0.51×0.55nm, 0.53×0.56nm) (SiO 2 / Al 2 o 3 =61) Roast at 550°C to remove the template agent, exchange 4 times with ammonium nitrate solution in a water bath at 80°C, and roast at 550°C after the exchange to obtain HZSM-5 molecular sieve, then perform selective modification, and then combine with The binder and the pore structure modifier are mixed and molded into a solid catalyst named TMMC-709.

Embodiment 2

[0015] Use the TMMC-709 catalyst prepared in embodiment 1, carry out toluene methanol alkylation reaction on fixed-bed reactor, toluene methanol feeds simultaneously, and reaction condition is: toluene / methanol (molecular ratio)=8 / 1, 4 / 1, 2 / 1, 1 / 1, toluene methanol weight space velocity is 2 hours -1 , N 2 The flow rate was 30ml / min and the temperature was 420°C. Using Varian 3800 gas chromatography, CP-WAX 52CB capillary chromatographic column (25m × 0.25mm) online analysis product distribution (normalized after removing toluene), the results are shown in Table 1.

[0016] When feed toluene / methanol molecular ratio is respectively 8 / 1, 4 / 1, 2 / 1, 1 / 1, the selectivity of p-xylene among xylene isomers in the product is respectively 89.53%, 91.92%, 90.71%, 91.90%, remained basically unchanged; the selectivity of C1-C5 low-carbon hydrocarbons in the product increased, respectively 6.97%, 12.04%, 19.88%, 29.19%; especially the molecular ratio of p-xylene to ethylene in the produ...

Embodiment 3

[0023] Use the TMMC-709 catalyst prepared in Example 1 to carry out the alkylation reaction of toluene methanol on a fixed-bed reactor, toluene methanol is fed simultaneously, and the reaction conditions are: toluene / methanol (mol ratio)=2: 1, toluene methanol Weight airspeed for 2 hours -1 , N 2 The flow rates were 10, 20, 30, 40 ml / min, and the temperature was 420°C. Using Varian 3800 gas chromatography, CP-WAX 52CB capillary chromatographic column (25m × 0.25mm) online analysis product distribution (normalized after removing toluene), the results are shown in Table 2.

[0024] when passing N 2 When the flow rate changes and the contact time is 0.77 seconds, 0.96 seconds, 1.28 seconds, and 1.92 seconds, the selectivity of p-xylene in the product to xylene isomers decreases, which are 93.81%, 90.97%, 85.22%, and 84.24% respectively; C in the product 1 -C 5The selectivity of low-carbon hydrocarbons is respectively 13.40%, 17.76%, 14.89%, 12.30%; the molecular ratio of p-x...

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Abstract

The method of toluene methylating to produce p-xylene and co-product low carbon olefin is that one kind of catalyst is used in producing p-xylene in high selectivity while co-producing ethylene and propylene. During the production, toluene and methylated reagent are fed simultaneously and different operation conditions are adopted so as to reach the selectivity of p-xylene in p-xylene isomers as high as 85-95 %, the selectivity of ethylene and propylene in C1-C5 low carbon hydrocarbons as high as 70-85 %, and the regulation of the molecular ratio between p-xylene and ethylene in the product.

Description

technical field [0001] The invention relates to a method for producing p-xylene through methylation of toluene and co-production of low-carbon olefins, in particular, it relates to a method for producing p-xylene with high selectivity through a reaction process and using a catalyst while producing p-xylene with high selectivity. Co-production of ethylene and propylene. Background technique [0002] P-xylene is an important organic chemical raw material, which is mainly used to synthesize terephthalic acid or dimethyl terephthalate; ethylene is the most important and basic chemical raw material in the chemical industry, and one of its uses is to prepare ethylene glycol Alcohol; Terephthalic acid reacts with ethylene glycol to obtain polyester with excellent properties, which is widely used as raw materials for fibers, films and plastics. At present, p-xylene production mainly uses toluene, C 9 Aromatics and mixed xylenes are used as raw materials, which are produced by disp...

Claims

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Application Information

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IPC IPC(8): C07C15/08C07C11/04C07C11/06C07C2/00C07C1/00
CPCY02P20/52
Inventor 许磊华邦嵩刘中民张新志
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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