Process for electrolytic reduction preparation of metanilic acid

A technology of aminobenzenesulfonic acid and sodium nitrobenzenesulfonate, applied in the field of electrochemistry, can solve problems such as slow reaction speed, long production cycle, and environmental pollution, and achieve the effects of easy reaction, small scale effect, and good selectivity

Inactive Publication Date: 2005-04-13
SHANGHAI CHLOR ALKALI CHEM
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Problems solved by technology

This method has the following defects in the operation process: the yield is low, and the quality is also poor, consumes a large amount of sulfuric acid, produces a large amount of waste acid, iron sludge, and the consumption of reaction raw materials is large, the reaction speed is slow, the production cycle is long, and it is harmful to the environment. Serious pollution, in addition, there are many problems in nitro reduction
[0009] The traditional method of preparing m-aminobenzenesulfonic acid uses Fe powder as catalyst reduction, in the actual production process, a large amount of iron sludge will be produced, polluting the environment

Method used

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  • Process for electrolytic reduction preparation of metanilic acid

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Embodiment 1

[0030] A lead electrode is placed in the cathode chamber of the electrolytic cell as a working electrode, and a lead electrode is placed in the anode chamber as a counter electrode. Weigh 112.5 grams of sodium m-nitrobenzenesulfonate, dissolve in a small amount of water, add 5 ml of 5M sulfuric acid, add water to 250 ml, and make an electrolyte solution with a raw material concentration of 2.0 mol / L, add it to the cathode chamber of the electrolytic cell, and start the circulation pump. Heat to 40°C; add 5M sulfuric acid into the anode chamber as electrolyte. Electrolysis was carried out for 8 hours at a current intensity of 10A. After the electrolysis, the electrolytic solution was cooled to 4° C., crystallized, and filtered to obtain the m-aminobenzenesulfonic acid product. The yield of m-aminobenzenesulfonic acid was 96.49%.

Embodiment 2

[0032] A copper electrode is placed in the cathode chamber of the electrolytic cell as a working electrode, and a lead electrode is placed in the anode chamber as a counter electrode. Weigh 5.6 grams of sodium m-nitrobenzene sulfonate, dissolve in a small amount of water, add 40 ml of 5M sulfuric acid, add water to 250 ml, make an electrolyte solution with a raw material concentration of 0.1 mol / L, and add it to the cathode chamber of the electrolytic cell. Turn on the circulating pump and heat to 40°C; add 0.1M sulfuric acid to the anode chamber, and conduct electrolysis at a current intensity of 2A for 2 hours. The yield of aminobenzenesulfonic acid was 92.6%.

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Abstract

The electroreduction process of preparing m-aminobenzene sulfonic acid includes the following steps: setting the sulfuric acid water solution of sodium m-aminobenzene sulfonate as electrolyte in the cathode chamber of isolated electrolytic bath; setting sulfuric acid water solution in the anode chamber of isolated electrolytic bath; electrolysis at 0-60 deg.c at current strength of 2-5 A for 2-5 hr; cooling the electrolyte after electrolysis to obtain crystal; and filtering to obtain m-aminobenzene sulfonic acid product. The process of the present invention is clean, needs no addition of oxidant and reductant, has mild condition, high selectivity, yield as high as 96 %, saving in power, easy-to-control reaction speed via current regulation, etc.

Description

technical field [0001] The invention relates to a method for preparing m-aminobenzenesulfonic acid, which is a method for preparing m-aminobenzenesulfonic acid through electrolytic reduction of m-nitrobenzenesulfonic acid, and belongs to the field of electrochemistry. Background technique [0002] Aminobenzenesulfonic acid is an important chemical intermediate, which is widely used in the production of vat dyes, azo dyes, sulfur dyes and reactive dyes, as well as in the production of anticancer drugs, pesticides, developers and rhodamine, etc. From the 1950s to the present, the traditional method of preparing m-aminobenzenesulfonic acid is sulfonation of m-nitrobenzene and oleum, and then reduction with iron powder. This method has the following defects in the operation process: the yield is low, and the quality is also poor, consumes a large amount of sulfuric acid, produces a large amount of waste acid, iron sludge, and the consumption of reaction raw materials is large, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25B3/25
Inventor 蔡华明陈斌武肖菊兰他芸莉陆嘉星陈黎明薛腾王欢
Owner SHANGHAI CHLOR ALKALI CHEM
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