Method for preparing 2-nitro-4-methylsulfonylbenzoic acid through indirect electro-oxidation

A technology of thiamphenicol benzoic acid and thiamphenicol toluene, which is applied in the field of indirect electrooxidation to prepare o-nitro-p-thiamphenicol benzoic acid, can solve the problems of easy decomposition, weak hydrogen peroxide oxidation ability, and large amount of hydrogen peroxide, and avoid Environmental pollution problems, oxidant cost savings, and high raw material utilization

Inactive Publication Date: 2015-07-29
JIAXING UNIV
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

But the oxidation ability of hydrogen peroxide is relatively weak, and it is very easy to decompose, very unstable. Generally, hydrogen peroxide is used as an oxidizing agent in a large amount, and the waste is very serious.
Therefore, hydrogen peroxide, a clean and environmentally friendly oxidant, cannot be used in many reactions
Such as European patent WO:2004 / 058698 A1 has introduced the technique that obtains o-nitro-p-thiamphenicol benzoic acid by oxidation with hydrogen peroxide, and the consumption of hydrogen peroxide is very large, is 10 times of stoichiometric, although this method has avoided the pollution of nitrogen dioxide, And the production rate is acceptable, but the problem of the amount of hydrogen peroxide makes the production cost too high, which not only causes serious waste, but also cannot realize industrialized production

Method used

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  • Method for preparing 2-nitro-4-methylsulfonylbenzoic acid through indirect electro-oxidation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Indirect Electrooxidation Preparation of o-nitro-p-thiamphenicol Benzoic Acid

[0020] In the 250ml reactor, add the sulfuric acid of 43g concentration 6mol / L, 4g chromium trioxide, the reactor is connected with stirrer, thermometer, condenser. Start stirring and heating. When the temperature rises to 90°C, add 4.3g of o-nitro-p-thiamphenicol toluene, and react at a constant temperature at this temperature for 6 hours. Cool the reaction solution to below 30°C, filter and wash and dry to obtain a solid of 3.81 g, The yield of o-nitro-p-thiamphenicol benzoic acid is 38.68%. The filtrate after suction filtration is Cr 3+ mother liquor. Titration of Cr in Mother Liquor by Ferrous Ammonium Sulfate Titration 6+ After content, the mother liquor is sent to the electrolytic cell for electrolysis. The electrolytic cell is a self-made plate-and-frame electrolytic cell. The length-to-height ratio of the cathode and anode chambers is 6:1:9. The membrane used is a cation exchange...

Embodiment 2

[0022] Indirect Electrooxidation Preparation of o-nitro-p-thiamphenicol Benzoic Acid

[0023] In the 250ml reactor, add the sulfuric acid of 43g concentration 7mol / L, 8g chromium trioxide, the reactor is connected with stirrer, thermometer, condenser. Start stirring and heating. When the temperature rises to 90°C, add 4.3g of o-nitro-p-thiamphenicol toluene, and react at this temperature for 6 hours. g, the yield of o-nitro-p-thiamphenicol benzoic acid was 42.65%. The filtrate after suction filtration is Cr 3+ mother liquor. Titration of Cr in Mother Liquor by Ferrous Ammonium Sulfate Titration 6+ After content, the mother liquor is sent to the electrolytic cell for electrolysis. The electrolytic cell is a self-made plate-and-frame electrolytic cell. The length-to-height ratio of the cathode and anode chambers is 6:1:9. The membrane used is a cation exchange membrane, and the cathode and anode are Pb / PbO respectively. 2 plate and stainless steel plate, the catholyte is 7m...

Embodiment 3

[0025] Indirect Electrooxidation Preparation of o-nitro-p-thiamphenicol Benzoic Acid

[0026] In the 250ml reactor, add the sulfuric acid of 103.2g concentration 7mol / L, 16g chromium trioxide, the reactor is connected with stirrer, thermometer, condenser. Start stirring and heating. When the temperature rises to 90°C, add 17.2g of o-nitro-p-thiamphenicol toluene, and react at a constant temperature for 6 hours at this temperature. g, the yield of o-nitro-p-thiamphenicol benzoic acid is 43.28%. The filtrate after suction filtration is Cr 3+ mother liquor. Titration of Cr in Mother Liquor by Ferrous Ammonium Sulfate Titration 6+ After content, the mother liquor is sent to the electrolytic cell for electrolysis. The electrolytic cell is a self-made plate-and-frame electrolytic cell. The length-to-height ratio of the cathode and anode chambers is 6:1:9. The membrane used is a cation exchange membrane, and the cathode and anode are Pb / PbO respectively. 2 plate and stainless st...

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Abstract

The invention discloses a method for preparing 2-nitro-4-methylsulfonylbenzoic acid through indirect electro-oxidation. The method comprises the process as follows: (a), chromium trioxide is dissolved in sulfuric acid, and a sulfuric acid solution of chromium trioxide is prepared; (b), 2-nitro-4-methylsulfonyltoluene is subjected to liquid-phase oxidation through the sulfuric acid solution of chromium trioxide, and 2-nitro-4-methylsulfonylbenzoic acid is obtained; (c), Cr <6+> / Cr<3+> is taken as a medium, Cr<3+> filtrate obtained from the step b is sent to an electrolytic bath for electrolysis, Cr<3+> is subjected to electrochemical oxidation to generate Cr<6+> again, Cr<6+> enters a reactor and continuously reacts with 2-nitro-4-methylsulfonyltoluene, and accordingly, an oxidizing agent is recycled. According to the method, the oxidability of high-valence chromium is higher than that of nitric acid, and the oxidation selectivity is better; by comparison with an existing nitric acid oxidation method, a highly-toxic reagent vanadium pentoxide is avoided, the waste acid recovery step is omitted, the oxidizing agent is recycled, and the production cost is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of organic chemistry, in particular to a method for preparing o-nitro-p-thiamphenicol benzoic acid by indirect electrooxidation. Background technique [0002] O-nitro-p-thiamphenicol benzoic acid is an important organic intermediate, and its preparation can use o-nitro-p-thiamphenicol toluene as a raw material, and oxidize its methyl group to obtain the corresponding acid. Since the benzene ring of o-nitro-p-thiamphenyltoluene has two electron-withdrawing groups and the melting point of the oxidation product is relatively high, it is difficult to oxidize and control the degree of oxidation. When the temperature is too high, the thiamphenicol group is easy to fall off, and the o-nitro-p-thiamphenicol toluene will have a wrapping phenomenon, which makes the reaction difficult to carry out. And when the temperature is lower, the oxidation yield is lower. U.S. United States Patent 5,424,481 has introduced the ...

Claims

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Application Information

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IPC IPC(8): C25B3/02C07C317/44C25B3/23
Inventor 屠晓华吴建一缪程平李宁张洋沈静飞蔡丽玲
Owner JIAXING UNIV
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