Method of low-temperature catalytic dechlorination of chlorophenol

A technology of chlorinated phenol and low-temperature catalysis, which is applied in the direction of chemical instruments and methods, preparation of organic compounds, physical/chemical process catalysts, etc., can solve the problems of low reaction efficiency, achieve the effect of improving catalytic performance and good industrialization prospects

Inactive Publication Date: 2009-10-28
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The present invention improves the catalytic performance of the Pd catalyst by adding the alkali dechlorination reagent in batches, so that the rea

Method used

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  • Method of low-temperature catalytic dechlorination of chlorophenol
  • Method of low-temperature catalytic dechlorination of chlorophenol
  • Method of low-temperature catalytic dechlorination of chlorophenol

Examples

Experimental program
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Effect test

Embodiment 1

[0021] Grind coconut shell activated carbon and sieve to obtain activated carbon powder of 300-400 mesh. Add a certain amount of activated carbon to 10wt.% nitric acid, stir in 80°C water bath for 2 hours, then filter and wash with distilled water until neutral. Water steam is then processed, dried, and set aside. Palladium chloride is dissolved in 10wt.% hydrochloric acid aqueous solution, dubbed 1.7 * 10 -2 mol / L palladium chloride solution. Add 10g of activated carbon treated with nitric acid into 165ml of prepared palladium chloride aqueous solution, immerse for 2 hours, then add 8ml of formaldehyde for reduction, and at the same time add saturated sodium bicarbonate solution dropwise, control the pH value to about 9, and react until the pH value is low. Change. Filter and dry to obtain a Pd / C catalyst with a Pd content of 5 wt.%.

[0022] The reaction process is that 0.648g (5mmol) p-chlorophenol, 0.511g (5mmol) triethylamine, 0.10g 5wt.% Pd / C catalyst, and 50ml methan...

Embodiment 2

[0024] Palladium chloride is dissolved in 10wt.% hydrochloric acid aqueous solution, dubbed 1.7 * 10 -2 mol / L palladium chloride solution, get 85ml, add 10g coconut shell activated carbon (300 mesh) processed by the method of Example 1 and soak for 2h, then add 8ml formaldehyde for reduction, drip saturated sodium bicarbonate solution simultaneously, control the pH value is about 9, react until the pH value remains unchanged, filter and dry to obtain a Pd / C catalyst with a Pd content of 2.5wt.%.

[0025] The reaction process is that 0.648g of p-chlorophenol, 0.20g of 2.5wt.% Pd / C catalyst, and 50ml of methanol solution are added to a 100ml three-necked flask with a mechanical stirring device, and the temperature is controlled at -15 to -10°C with an ice-salt solution bath. After the replacement of hydrogen in the kettle for 6 times, under the condition that the hydrogen pressure is atmospheric pressure, turn on the mechanical agitation, and the rotating speed is 500rpm. During...

Embodiment 3

[0027] Get 0.10g of 5wt.%Pd / C catalyst prepared in Example 1, 0.643g of o-chlorophenol, and 0.511g of triethylamine and put them into 50ml of methanol solution to make a suspension, add it to a 100ml three-port Flask, other reaction conditions are identical with embodiment 1, by certain time interval, continuous sampling, learn with gas chromatographic analysis, reaction product is phenol, does not detect other compounds to generate. The results are shown in Table 1.

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Abstract

The invention discloses a method of low-temperature catalytic dechlorination of chlorinated aromatic hydrocarbons. The method uses chlorophenol as pollutant, in the presence of Pd, uses hydrogen as a reducing agent and hydrogen pressure as atmospheric pressure, controls temperature in the range of 258 to 273k, adds a triethylamine dechlorination reagent in batches, carries out catalytic hydrogenation and dechlorination reaction in organic solvent, and can remove 5 to 20 moles of chlorine per mole of Pd catalyst per minute, and phenol produced in a high selectivity way can be recycled. Through simple filtration, the Pd catalyst can be reused for plural times without losing activity. The process of the invention can be effectively used for low-temperature catalytic hydrogenation and dechlorination for chlorinated aromatic compounds, and has good prospect for industrialization in environmental protection.

Description

technical field [0001] The invention belongs to the technical field of catalytic dechlorination environmental protection, and particularly relates to a method for low-temperature catalytic hydrogenation dechlorination of chlorinated aromatic phenols to eliminate chlorinated aromatic hydrocarbon pollutants in the environment. Background technique [0002] Chlorinated aromatics are widely used as solvents, flavor enhancers, insect repellents, fungicides and many organic synthesis intermediates. However, due to its severe toxicity and strong bioaccumulation, it has aroused people's attention to health and environment. This compound is difficult to degrade, and its accumulation in adipose tissue can trigger gene mutations that lead to cancer. It is difficult to completely decompose chlorinated aromatics into CO by direct combustion and biodegradation 2 , H 2 O and HCl, many researchers are now working on a new dechlorination method, which can significantly reduce the toxicity...

Claims

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Application Information

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IPC IPC(8): C07C39/04C07C37/00B01J23/44A62D3/34A62D101/28
CPCY02P20/52
Inventor 金中豪王幸宜李到
Owner EAST CHINA UNIV OF SCI & TECH
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