New method for preparing p-chlorotoluene through selective chlorination of toluene

A p-chlorotoluene, selective technology, applied in the chemical field, can solve the problems of high cost, large amount of molecular sieve, etc., and achieve the effect of easy separation, small amount of catalyst, and high selectivity

Inactive Publication Date: 2012-10-17
常州新东化工发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantage of this method is that the amount of ionic liquid used as a solvent is too large, the cost is high, and it is difficult to recover, purify and apply mechanically [Organic Chemistry 2011, 31(2), 227-230]
[0006] In the prior art, the disadvantage of the catalytic method of Lewis acid plus organic sulfur additive is that the organic sulfur additive has changed, it is difficult to recycle and apply mechanically, and the selectivity of p-chlor

Method used

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  • New method for preparing p-chlorotoluene through selective chlorination of toluene
  • New method for preparing p-chlorotoluene through selective chlorination of toluene

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0019] Example 1

[0020] Weigh 50g of toluene, 80mg of 1-methyl-3-n-hexylimidazole iron tetrachloride salt, and 1-methyl-3-n-hexylimidazole chloride salt ([HeMIM]Cl) uniformly and slowly ventilate chlorine for 8 hours in the dark under stirring. , The temperature of the whole process is controlled at 0℃, after the reaction is over, filter, wash with water, dry with anhydrous sodium sulfate, and filter. Sampling was performed for gas chromatographic detection, the toluene conversion rate was 95%, and the content ratio of p-chlorotoluene to o-chlorotoluene was 3.1:1.

Example Embodiment

[0021] Example 2

[0022] Weigh 50g of toluene, 80mg of 1-methyl-3-n-octylimidazole aluminum tetrachloride ionic liquid, 1-methyl-3-n-hexylimidazole chloride salt ([HeMIM]Cl) and let chlorine gas evenly and slowly under stirring under the dark For 8 hours, the temperature in the whole process was controlled at 25°C. After the reaction, it was filtered, washed with water, dried with anhydrous sodium sulfate, and filtered. Sampling for gas chromatographic testing, the toluene conversion rate was 92%, and the content ratio of p-chlorotoluene to o-chlorotoluene was 2.6:1.

Example Embodiment

[0023] Example 3

[0024] Weigh 50g of toluene, 80mg of 1-methyl-3-n-hexylimidazole aluminum tetrachloride salt, and 1-methyl-3-n-hexylimidazole chloride salt ([HeMIM]Cl) uniformly and slowly ventilate chlorine for 8 hours in the dark under stirring. , The temperature of the whole process is controlled at 50°C, after the reaction is over, filter, wash with water, dry with anhydrous sodium sulfate, and filter. Sampling was carried out for gas chromatography detection, the conversion rate of toluene was 96%, and the content ratio of p-chlorotoluene to o-chlorotoluene was 2.8:1.

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Abstract

The invention provides a new method for preparing p-chlorotoluene through selective chlorination of toluene. The new method comprises the steps as follows: 1) mixing alkylimidazolium chloride ionic liquid with lewis acid to obtain lewis acid type ionic liquid, wherein R1 and R2 are C1 to C8 alkyl group, and MCln is lewis acid such as ferric trichloride, aluminium trichloride and antimony trichloride; 2) taking the lewis acid type ionic liquid as catalyst to be added in toluene solution, introducing chlorine gas in dark, controlling the temperature at 0-50 DEG C in the whole chlorination process, and controlling the chlorine introduction amount so as to enable the conversion percent of the toluene to be larger than 85%; and (3), cooling, and then filtering the ionic liquid to obtain the toluene monochloride mixture solution. After being applied for toluene ring chlorination as the catalyst, the advantages of small catalyst use amount, high selectivity to p-chlorotoluene, easy separation, and applicability are provided.

Description

technical field [0001] The invention belongs to the technical field of chemistry and relates to a new method for preparing p-chlorotoluene by selective chlorination of toluene. Background technique [0002] Using chlorine gas as a chlorination agent to chlorinate toluene to co-produce o-chlorotoluene and p-chlorotoluene is a commonly used method in industry. Due to the low activity of toluene, the reaction usually needs to be catalyzed by adding a catalyst. [0003] When chlorine gas is used as the chlorination agent to carry out ring chlorination of toluene, Lewis acid is often used as a catalyst. 3 , AlCl 3 , SbCl 3 , SbCl 5 , SnCl 4 etc. Iron powder can also be used. However, when toluene ring chlorination is carried out only with Lewis acid as catalyst, p-chlorotoluene / o-chlorotoluene only reaches 1:3. After adding different sulfur-containing organic substances as auxiliary agents, the para-selectivity can be improved [US 4647709, US 5105036]. The disadvantage of t...

Claims

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Application Information

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IPC IPC(8): C07C25/02C07C17/12B01J31/02
Inventor 王明亮顾留杰毛素华朱成明王顺利叶春林葛裕华
Owner 常州新东化工发展有限公司
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