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Method for catalyzing chlorination of alkylbenzene ring by using combined catalyst

A catalyst that catalyzes alkylbenzene rings and combined technology, applied in chemical instruments and methods, organic compound/hydride/coordination complex catalysts, physical/chemical process catalysts, etc., can solve the problem of insignificant improvement in para-selectivity , affect separation and other issues, to achieve the effect of easy separation and improved selectivity

Active Publication Date: 2012-09-12
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of using inorganic sulfide as a cocatalyst is that the para-selectivity is not significantly improved, and the disadvantage of organic sulfur compound catalyst is that it is difficult to remove from the chlorinated mixture, which affects the subsequent separation

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Weigh 30g of toluene, 20mg of iron powder, 20mg of elemental sulfur, 10mg of 4-methylbenzenehydroxamic acid, and evenly and slowly pass chlorine gas for 3-5 hours under dark stirring, the temperature range of the whole process is controlled at 0-10°C, and the reaction is over Afterwards, filter, wash with water, dry over anhydrous sodium sulfate, and filter. Sampling was carried out for gas chromatography detection, and the toluene conversion rate was 97.5%, the content ratio of p-chlorotoluene and o-chlorotoluene was about 1.22, and the content of m-chlorotoluene was 0.2%.

Embodiment 2

[0021] Weigh 30g of toluene, 20mg of iron powder, 20mg of elemental sulfur, 10mg of 2,4-dichlorobenzene hydroxamic acid, and evenly and slowly pass chlorine gas for 3-5 hours while stirring in the dark, and the temperature range of the whole process is controlled at 0-10°C. After the reaction, filter, wash with water, dry over anhydrous sodium sulfate, and filter. Sampling was carried out for gas chromatography detection, and the toluene conversion rate was 97.0%, the content ratio of p-chlorotoluene and o-chlorotoluene was about 1.13, and the content of m-chlorotoluene was 0.15%.

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PUM

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Abstract

The invention discloses a method for catalyzing chlorination of alkylbenzene ring by using a combined catalyst. The method comprises the following steps: adding iron powder or Lewis acid which serves as a primary catalyst into a toluene liquid, adding a composition of an elementary substance sulfur and hydroxamic acid, which serves as a cocatalyst, introducing chorine under the condition of keeping out of the sun, controlling the temperature within 0-70DEG C in the whole chlorination process, and controlling the chlorine introducing amount to ensure that the conversion rate of toluene is over 97 percent. After the combined cocatalyst is applied to the chlorination of a benzene ring, the selectivity of a product, namely parachlorotoluene is effectively improved, the selectivity of the parachlorotoluene is over 50 percent and the catalyst is easy to separate.

Description

technical field [0001] The invention relates to a composition of inorganic element sulfur and organic hydroxamic acid, which can be used as an auxiliary catalyst in the chlorination of alkylbenzene rings, and can effectively improve the selectivity of para-products in the chlorination of alkylbenzene rings . Background technique [0002] Alkylbenzene ring chlorination is an important reaction. For example, toluene ring chlorination can be used to prepare p-chlorotoluene with multiple uses, and o-xylene ring chlorination can be oxidized into a polyamide An important intermediate of imines is p-chlorophthalic acid. However, ring chlorination to produce these compounds produces both monochlorinated ortho isomers and polychlorinated by-products. [0003] Due to the low activity of alkylbenzene, it is usually necessary to add a catalyst for catalysis. According to different catalyst systems, alkylbenzene ring chlorination can be divided into molecular sieve catalytic reaction s...

Claims

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Application Information

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IPC IPC(8): C07C17/12C07C25/02B01J31/02
Inventor 王明亮叶春林葛裕华俞志宏陶文平
Owner SOUTHEAST UNIV
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