Method for preparing o-chlorotoluene

A technology for o-chlorotoluene and dichlorotoluene, applied in the field of catalytic reduction to prepare o-chlorotoluene, can solve problems such as product waste, and achieve the effects of long service life and high conversion rate

Inactive Publication Date: 2018-09-28
江苏超跃化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem of waste of the above-mentioned side reaction products, the present invention provides a method that uses more than one of 2,3-dichlorotoluene, 2,4-dichlorotoluene and 2,5-dichlorotoluene as a raw material and hydrogen as a reducing agent , the method for preparing o-chlorotoluene by catalytic reduction of supported palladium catalyst

Method used

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  • Method for preparing o-chlorotoluene

Examples

Experimental program
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Effect test

Embodiment 1

[0021] 1. The specific surface area of ​​25g is greater than 100m 2 / g, silicon carbide cylindrical particles with a diameter of 2-4mm, impregnated and adsorbed with 10ml of aqueous solution containing 5% tetraammonium palladium chloride, dried naturally at 110°C for 5 hours before use.

[0022] 2. Fill 25g of hydrogenation catalyst in a cylindrical reactor with a diameter of 20mm, raise the temperature to 200°C, and keep the hydrogen atmosphere after passing hydrogen for one hour; keep the reaction pressure at 0.05MPa, and continuously add 2,3-dihydrogen at 0.3ml / h The mixture of chlorotoluene, 2,4-dichlorotoluene and 2,5-dichlorotoluene was sampled after reacting for 1 hour and analyzed by gas chromatography.

[0023] The result is as follows:

[0024]

Embodiment 2

[0026] The mixture of 2,3-dichlorotoluene, 2,4-dichlorotoluene and 2,5-dichlorotoluene in Example 1 was replaced by 2,5-dichlorotoluene, and the others were the same as in Example 1.

[0027] The result is as follows:

[0028]

Embodiment 3

[0030] The silicon carbide-supported palladium catalyst in Example 1 was replaced by an activated carbon-supported palladium catalyst, and the others were the same as in Example 1.

[0031] The result is as follows:

[0032]

[0033] It can be seen that the activated carbon-supported palladium catalyst has a catalytic selectivity effect inferior to that of the silicon carbide-supported palladium catalyst, and industrial production preferably selects the activated carbon-supported palladium catalyst provided by the invention.

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Abstract

The invention provides a method for preparing dichlorotoluene, and relates to the field of preparation of organic intermediates. The method provided by the invention uses more than one of 2,3-dichlorotoluene, 2,4-dichlorotoluene and 2,5-dichlorotoluene as raw materials, and uses supported palladium as a catalyst to prepare o-chlorotoluene by continuous reaction in a fixed bed. The method providedby the invention uses industrial by-products 2,3-dichlorotoluene, 2,4-dichlorotoluene and 2,5-dichlorotoluene as the raw materials; the supported palladium catalyst has good selectivity and long service time and realizes high yield of o-chlorotoluene.

Description

technical field [0001] The invention relates to a preparation method of o-chlorotoluene, in particular to the catalytic reduction of more than one of 2,3-dichlorotoluene, 2,4-dichlorotoluene and 2,5-dichlorotoluene to prepare o-chlorotoluene toluene. Background technique [0002] 2,3-dichlorotoluene, 2,4-dichlorotoluene and 2,5-dichlorotoluene are side reaction products obtained in some industrial production, and basically exist in the form of a mixture. Currently they are only used as solvents, causing extreme Big waste. Therefore, the treatment of the mixture is of great significance to protect the environment and obtain economic benefits. [0003] O-chlorotoluene is an important chemical raw material intermediate, widely used in pesticides, medicines, dyes and paints. It is also a medium-boiling organic solvent with good performance. There is a good market prospect. For example, o-halogenotoluene is increasingly widely used in organic synthesis; using o-chlorotoluene...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C25/02C07C17/23B01J27/224B01J23/44
CPCB01J23/44B01J27/224C07C17/23C07C25/02
Inventor 殷云武任坚跃薛保安
Owner 江苏超跃化学有限公司
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