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Method for preparing dimethylbenzene

A xylene and toluene technology, applied in the field of xylene preparation, can solve problems such as waste and increased separation costs

Active Publication Date: 2010-06-09
MICROVAST POWER SYST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The total selectivity of xylene in the product ranges from 53.2% to 69.7%, and secondly, the selectivity of aliphatic compounds is also relatively high (15.4% to 27.6%), and aliphatic compounds are mainly converted from halomethane, which affects the price. Higher methyl halide feedstock is not a small waste, but also increases the cost of separation

Method used

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  • Method for preparing dimethylbenzene
  • Method for preparing dimethylbenzene
  • Method for preparing dimethylbenzene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Catalyst preparation:

[0051] Weigh 6.300g of oxalic acid solid and dissolve it in 100mL deionized water to obtain solution A, and weigh 0.10224g of RhCl 3 ·3H 2 O was dissolved in 50 mL of deionized water to obtain solution B, and 34.5831 g of tetraethoxysilane liquid was weighed and added to solution A to form two mutually immiscible liquids. After sealing and stirring for 1 hour, the solution becomes a uniform colorless and transparent homogeneous solution. Add solution B and continue to stir for 0.5 hours. Then put the mixed solution in a 120°C oven and dry it until it becomes a colloidal solid, and then put the colloidal solid in Heat up to 900°C at a heating rate of 200°C / h in the muffle furnace, maintain the temperature for 10 hours and then cool down. After the temperature drops to room temperature, take out the catalyst, sieve to 20-60 mesh, and finally get 0.40% Rh / SiO 2 -900-10 catalyst ("0.40%" indicates the mass percentage of the corresponding metal, "-9...

Embodiment 2～6

[0057] Catalyst preparation:

[0058] According to the preparation method of catalyst in embodiment 1, use the RhCl of different concentration 3 ·3H 2 O solution 50.0mL deionized water to obtain solution B, wherein RhCl 3 ·3H 2 The concentration of the O solution is the conversion amount of the required different mass fractions of Rh. Each catalyst shown in Table 1 was obtained.

[0059] Catalyst Test:

[0060] According to the testing conditions of the catalyst in Example 1, the reaction was carried out under the same reaction conditions. The experimental results are listed in Table 1.

[0061] Table 1 Experimental results of Examples 1 to 6 (influence of Rh content)

[0062]

Embodiment 7～12

[0064] Catalyst preparation:

[0065] According to the preparation method of the catalyst in Example 1, different calcination temperatures and times were used in the muffle furnace. Catalysts with different specific surface areas, namely the respective catalysts shown in Table 2, were finally obtained.

[0066] Catalyst Test:

[0067] According to the test method of the catalyst in Example 1, the reaction was carried out under the same reaction conditions. The experimental results are listed in Table 2.

[0068] Table 2 Experimental results of Example 1 and Examples 7-12 (influence of calcination temperature during catalyst preparation, catalyst composition 0.40%Rh / SiO 2 )

[0069]

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Abstract

The invention discloses a method for preparing dimethylbenzene, comprising on modified HZSM-5 molecular-sieve-based catalyst, adopting methyl bromide as methylation reagent, leading the methyl bromide to react with methylbenzene, and generating the target product dimethylbenzene and byproduct hydrogen bromide. The method has the advantages of comparatively low reaction temperature, higher conversion rate of reactant, less by product, long service life of the catalyst, high efficiency and low cost.

Description

technical field [0001] The present invention relates to a method for preparing xylene from toluene. Background technique [0002] Xylene, also known as mixed xylene, is a mixture of p-xylene, o-xylene, m-xylene and ethylbenzene. The mixture is mainly used as a solvent for paint coatings and as an additive for aviation gasoline. When used as a chemical raw material, each isomer can be separated in advance. Among them, p-xylene is an important chemical raw material, the most important application (accounting for more than 80%) is used to produce PTA (terephthalic acid) and DMT (dimethyl terephthalate), and these two substances are It is mainly used in the synthesis of PET (polyester); p-xylene is also a commonly used organic solvent and can also be used in the synthesis of pharmaceutical intermediates. [0003] The common method for industrial production of xylene is toluene selective disproportionation catalytic technology. Exxon Mobil proposed the MSTDP and MTPX toluene ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C1/26B01J29/40
CPCC07C2/861Y02P20/52C07C15/08
Inventor 周小平李文生章晶杰夫·徐
Owner MICROVAST POWER SYST CO LTD
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