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Method for selectively synthesizing p-xylene

A p-xylene, selective technology, applied in the field of selective synthesis of p-xylene, can solve the problems of cumbersome operation, etc., and achieve the effects of saving cost, green raw materials, and reducing the size of the orifice

Active Publication Date: 2010-08-04
溧阳常大技术转移中心有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the cumbersome operation of pre-carbon deposition, it is currently limited to laboratory research

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Prepare H-ZSM-5 / MCM-41 as a catalyst with a mass ratio of 6:1 according to the above-mentioned method, wherein the silicon-aluminum ratio of H-ZSM-5 is 25:1, with toluene and dimethyl carbonate as raw materials, its The molar ratio is toluene: dimethyl carbonate 4:1, the reaction temperature is 380°C, and the mass space velocity of raw materials is 1h -1 , the conversion rate of toluene reached 26.7%, and the selectivity of p-xylene was 71.8%.

Embodiment 2

[0018] Prepare H-ZSM-5 / MCM-41 as a catalyst with a mass ratio of 6:1 according to the above-mentioned method, wherein the silicon-aluminum ratio of H-ZSM-5 is 50:1, with toluene and dimethyl carbonate as raw materials, the molar The ratio is toluene: dimethyl carbonate 4: 1, the reaction temperature is 380°C, and the mass space velocity of raw materials is 1h -1 , the conversion rate of toluene reached 23.2%, and the selectivity of p-xylene was 72.1%.

Embodiment 3

[0020] Prepare H-ZSM-5 / MCM-41 as a catalyst with a mass ratio of 6:1 according to the above method, wherein the silicon-aluminum ratio of H-ZSM-5 is 100:1, with toluene and dimethyl carbonate as raw materials, its The molar ratio is toluene: dimethyl carbonate 4:1, the reaction temperature is 380°C, and the mass space velocity of raw materials is 1h -1 , the conversion rate of toluene reached 20.5%, and the selectivity of p-xylene was 71.2%.

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Abstract

The invention relates to a method for selectively synthesizing p-xylene, which takes methyl carbonate and toluene as raw materials, and takes micro-mesoporous composite molecular sieves H-MCM-22 / MCM-41, H-MCM-22 / MCM-48, H-ZSM-5 / MCM-41 or H-ZSM-5 / MCM-48 as catalysts. Under the conditions that the reaction temperature is 200-400 DEG C, the mole ratio of the toluene to the methyl carbonate is 1:1-4:1, and the mass space velocity is 1-15h<-1>, better conversion of the raw materials and selectivity of target products can be obtained, and under the best conditions, the conversion of the toluene canreach 15.1 percent, and the selectivity of p-xylene can reach 80.8 percent. Compared with the traditional process, the method has environment-friendly raw materials, simple process and mild conditions. The preparation method of the micro-mesoporous composite molecular sieves is simple, greatly saves operation process compared with the traditional deposition method, and saves cost, and the effect of one-time modification is higher than that of the one-time modification of the traditional method.

Description

technical field [0001] The invention relates to a method for selectively synthesizing p-xylene, in particular to a method for synthesizing p-xylene by using a microporous-mesoporous composite molecular sieve as a catalyst. Background technique [0002] P-xylene is an important raw material in the fields of synthetic polyester fibers, pesticides, medicines, dyes and solvents. Terephthalic acid can be obtained after the oxidation of p-xylene, and then polyester, an important synthetic fiber and plastic raw material, can be obtained (Miduo, Wang Ye, 2004 World P-xylene Review, Chemical Technology Market, 2005, 8: 37-40). Therefore, the demand for p-xylene will increase year by year. At present, the industry mainly adopts mixed xylene isomerization, toluene and C9 aromatics disproportionation, and toluene selective disproportionation. Among them, the process of directly synthesizing high-concentration p-xylene by the alkylation reaction of toluene and methanol is the most rese...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C2/86
Inventor 李永昕薛冰徐崇福吴润泽梁鹏
Owner 溧阳常大技术转移中心有限公司
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