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Method for oxidation of benzene ring side chain containing electron-attracting groups by combination of ozone and nitric acid

An electron-withdrawing and benzene-ring technology, which is applied in the direction of organic chemical methods, chemical instruments and methods, and the preparation of organic compounds, can solve the problems of low oxidation conversion rate and difficulty in tail gas treatment, and achieve improved yield and treatment engineering Simplified, environmentally friendly effects

Active Publication Date: 2010-01-06
浙江嘉福新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the oxidation conversion rate promoted by air is still not high, and the yield is about 75%. Moreover, in the process of using a large amount of air, nitrogen dilutes the nitric oxide produced in the oxidation process and releases it as tail gas, which brings certain benefits to tail gas treatment. Difficulty, while the clean production process requires nitrogen emissions to be zero

Method used

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  • Method for oxidation of benzene ring side chain containing electron-attracting groups by combination of ozone and nitric acid

Examples

Experimental program
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Effect test

Embodiment 1

[0017] Adding 200g of sulfuric acid, 2.0g of vanadium pentoxide, and 18.6g of o-nitro-p-toluenesulfonic acid in a 250ml reactor was 70% (weight percent concentration, the same below). Insert the ozone ventilation tube below the liquid level, and install a stirring device, a thermometer, a dripping device, a condenser tube and a liquid receiver on the reactor. Turn on stirring and heating, and when the temperature rises to 140°C, introduce ozone (ozone gas is generated by an electrolytic ozone generator, and the amount of ozone generated is 0.8-20g / hr), and then start to drop nitric acid with a concentration of 65% through the dripping device 60ml, control the dropping rate (dropping is completed in about 9 hours), keep the reaction at this temperature for 10 hours, cool the reaction solution to below 30°C, filter and wash and dry to obtain 2-nitro-4-sulfonic acid The solid product of benzoic acid was 20.7g, the content of 2-nitro-4-sulfobenzoic acid was 94.6%, and the yield wa...

Embodiment 2

[0019] Add 200 g of 70% sulfuric acid, 2.0 g of vanadium pentoxide, and 20.0 g of o-nitro-p-thiamphenicol toluene into a 250 ml reactor. Insert the ozone ventilation tube below the liquid level, and install a stirring device, a thermometer, a dripping device, a condenser tube and a liquid receiver on the reactor. Turn on stirring and heating, and when the temperature rises to 155°C, introduce ozone (ozone gas is generated by an electrolytic ozone generator, and the amount of ozone generated is 0.8-20g / hr), and then start to drop nitric acid with a concentration of 65% through the dripping device 60ml, control the dropping rate (dropping is completed in about 6 hours), keep the reaction at this temperature for 7 hours, cool the reaction solution to below 30°C, filter and wash and dry to obtain 20.1g of solid product, 2-nitro The content of -4-thiamphenicol benzoic acid is 93.1%, and the yield is 82%. Obtain concentration 31% left and right nitric acid 87g in liquid receiver si...

Embodiment 3

[0021] Add 200 g of 70% sulfuric acid, 1.0 g of vanadium pentoxide, and 20.0 g of o-nitro-p-thiamphenicol toluene into a 250 ml reactor. Insert the ozone ventilation tube below the liquid level, and install a stirring device, a thermometer, a dripping device, a condenser tube and a liquid receiver on the reactor. Start stirring and heating, and when the temperature rises to 140°C, feed ozone (ozone gas is produced by an electrolytic ozone generator, and the amount of ozone produced is 0.8 to 20g / hr), and then start to drip 60ml of 65% nitric acid by the dripping device, Control the rate of addition (dropping is completed in about 12 hours), keep the reaction at this temperature for 13 hours, cool the reaction solution to below 30 ° C, filter and wash, and dry to obtain 20.3 g of solid product, 2-nitro-4 -The content of thiamphenicol benzoic acid is 94.1%, and the yield is 84%. Obtain concentration 35% left and right nitric acid 75g in the liquid receiver simultaneously.

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Abstract

The invention relates to a method of ozone-nitric acid coupled with oxidation containing electron-withdrawing group benzene ring side chain, which is characterized in that the containing electron-withdrawing group toluene is put into sulfate solution; the vanadium pentoxide catalyst is added; the nitric acid is dipped in, and simultaneously the ozone is joined for chemical reaction; after the reaction, the product is separated and purified. In the method, the ozone is uased as an accelerate oxidant with small intake quantity; as the air is not used in the reaction, the ozone oxidizes the nitric oxide oxidation to transform into the quinquevalent nitrogen, which can be recycled to reduce the contents of nitric acid. Thus the discharge amount of the nitric oxide is reduced and the output of the oxidation product is improved by 5 to 8%. With the product directly filtered from the acid liquor, the product purity can reach 94 to 95%, according to the liquid phase chromatogram analysis.

Description

technical field [0001] The invention relates to a method for ozone to promote the oxidation of side chains of benzene rings containing electron-withdrawing groups, and a method for combining ozone and nitric acid to oxidize the side chains of benzene rings containing electron-withdrawing groups. Background technique [0002] 2-nitro-4-thiamphenicol benzoic acid, 2-nitro-4-sulfonyl benzoic acid, o-chloro-4-thiamphenicol benzoic acid, etc. are important organic intermediates. The usual method for preparing this type of benzoic acid containing multiple electron-withdrawing groups is to use a strong oxidizing agent, such as potassium permanganate or nitric acid, to oxidize the side chain of the benzene ring in toluene containing electron-withdrawing groups to obtain the product, and use high Active di-aluminum pentoxide is used as the main catalyst. But the oxidation is more difficult and the conversion rate is lower. Nitric acid is a commonly used oxidant, and the commonly us...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07B41/08C07C317/22C07C309/40C07C315/04
Inventor 吴建一邓建军王宏亮申广照周幼红静桂兰
Owner 浙江嘉福新材料科技有限公司