Method for preparing dimethylbenzene through methylation and transalkylation

A technology of transalkylation and xylene, which is applied in the fields of organic chemistry, bulk chemical production, and double decomposition reaction to produce hydrocarbons. It can solve the problem of low xylene production and achieve good technical effects and maximize production capacity.

Active Publication Date: 2013-05-29
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] The technical problem to be solved by the present invention is that the xylene yield in the existing toluene disproportionation or toluene disproportionation and transalkylation technology is determined by the ring ratio of methylbenzene in the raw material, and the xylene yield is low and by-products when the heavy aromatics raw material is insufficient The problem of a large amount of benzene, providing a new method of methylation and transalkylation to produce xylene

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The weight composition is 0.15%Pt-1.5%Sn-0.5%La / 50%ZSM-5 / 50%SiO 2 Under the action of the catalyst M-1, anhydrous methanol is used as a methylation reagent, and mixed aromatics are reacted under the condition of hydrogen, and the molar ratio of hydrogen aromatics is 3.0. The reaction conditions and results are shown in Table 1:

[0024] Table 1 Reaction results of anhydrous methanol and mixed aromatics under the action of catalyst M-1

[0025] Composition of aromatic hydrocarbon feedstock, wt%

0.5B / 0.5D

0.7B / 0.3D

0.9B / 0.1D

Methylbenzene ring ratio, mol / mol

1.0

1.5

2.5

Reaction temperature, °C

450

350

300

Weight airspeed, h -1

15.0

5.0

2.0

Reaction pressure, MPa

0.5

1.5

2.0

Methylation reagent conversion rate, mol%

99.8

99.5

99.0

Aromatics conversion, mol%

47.6

42.8

35.1

Xylene selectivity, mol%...

Embodiment 2

[0029] 0.3% H in weight composition 2 SO 4 / 1.5%Ni / 50%MCM-41 / 20%β Molecular Sieve / 30%Al 2 o 3 Under the action of catalyst M-2, methanol with water content of 40% was used as a methylating agent to react with mixed aromatics under the condition of hydrogen, and the molar ratio of hydrogen to aromatics was 5.0. The reaction conditions and results are shown in Table 2:

[0030] Table 2 Reaction results of aqueous methanol and mixed aromatics under the action of catalyst M-2

[0031] Composition of aromatic hydrocarbon feedstock, wt%

[0032] If the proportion of methanol in the raw material is high, methanol will undergo a significant aromatization reaction. In the patented method, the aromatics conversion rate and xylene selectivity are not distinguished.

Embodiment 3

[0034] The weight composition is 0.7%Zr-1.2%H 2 SO 4 -1.0%Mo / 60%USY / 40%Al 2 o 3 Under the action of the catalyst M-3, dimethyl ether is used as a methylating agent to react with mixed aromatics under the condition of hydrogen, and the molar ratio of hydrogen to aromatics is 4.0. The reaction conditions and results are shown in Table 3:

[0035] Table 3 Reaction results of dimethyl ether and mixed aromatics under the action of catalyst M-3

[0036] Composition of aromatic hydrocarbon feedstock, wt%

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Abstract

The invention relates to a method for preparing dimethylbenzene through methylation and transalkylation, and mainly aims to solve the problems that the yield of dimethylbenzene is determined by the link relative ratio of methyl benzene in raw materials, and when a heavy aromatic raw material is insufficient, the output of the dimethylbenzene is low and a lot of byproduct benzene is generated at the same time in the existing toluene disproportionation or toluene disproportionation and transalkylation technologies. The problems are well solved by adopting the technical scheme which is s follows: the method comprises the following steps of: by using a methylation agent and aromatic hydrocarbons which has less than 12 Cs and does not contain or only contains a small amount of dimethylbenzene as raw materials, under the condition that the reaction temperature is 300-500 DEG C, the reaction pressure is between the normal pressure and 10.0MPa and the weight space velocity of the raw materials is 0.3-10h<-1>, contacting the raw materials with a solid acid catalyst to ensure that an alkylation reaction is performed on methanol and the aromatic hydrocarbons, and performing transalkylation among the aromatic hydrocarbons to obtain the dimethylbenzene. The method can be used in industrial production of dimethylbenzene.

Description

technical field [0001] The invention relates to a method for producing xylene through methylation and transalkylation. Background technique [0002] Xylene is one of the main basic organic raw materials in the petrochemical industry, and has a wide range of uses in many chemical production fields such as chemical fibers, synthetic resins, pesticides, medicines, and plastics. [0003] Industrially, xylene is mainly obtained by separation of catalytic reforming, catalytic cracking, coking process products and pyrolysis gasoline, and can also be produced by toluene disproportionation, benzene and carbon nine alkyl transfer, or by toluene and C 9-10 A and other heavy aromatics derived from methyl transfer. [0004] In recent years, there have been many research reports on catalysts for toluene disproportionation and / or transalkylation to produce xylene at home and abroad. U.S. Patent No. 5,475,179 discloses a catalyst for the disproportionation of toluene, which is SiO 2 The ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C6/06C07C2/88
CPCY02P20/52
Inventor 王雨勃孔德金龚燕芳郭宏利
Owner CHINA PETROLEUM & CHEM CORP
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