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Preparation method of 2,2'-dithio-salicylic acid

A technology of dithiosalicylic acid and liquid sulfur dioxide, applied in 2 fields, can solve the problems of large amount of production waste water, difficult to purify, low product yield and the like, and achieves low production cost, good product purity and high reaction yield. Effect

Inactive Publication Date: 2010-08-18
绍兴上虞洁源环保科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The problem to be solved by the present invention is to provide a synthetic method of 2,2'-dithiosalicylic acid which is simple in operation, safe and reliable in production, high in reaction yield, low in production cost, and environmentally friendly, and overcomes the product yield in the traditional process. Low efficiency, large amount of production wastewater, difficult to purify products, etc.

Method used

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  • Preparation method of 2,2'-dithio-salicylic acid

Examples

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Effect test

Embodiment 1

[0022] (1) Add 2800 liters of water to 5000 liters of enamel reaction kettle, drop into 400 kilograms of anthranilic acid (dry product, content ≥ 99%, 2.89Kmol), start stirring, add 800 liters of 30% industrial hydrochloric acid (density) in the kettle 1.15kg / L), cool down to 0-5°C with frozen brine, drop a solution consisting of 222kg of sodium nitrite (dry product, content ≥99%, 3.19Kmol) and 600kg of water into the kettle, and react for 2 hours Afterwards, the iodine was tested with potassium chloride starch test paper, the test paper turned blue and the reaction was completed, and about 4500 kg of diazo solution was obtained. (2) Add 300 kg of water, 5 kg of potassium iodide and 6 kg of copper sulfate to the reaction kettle, cool to -10°C, slowly add 370 kg of liquid sulfur dioxide (5.78Kmol) and the above-mentioned diazo solution, and keep warm for 2 hours after adding , be heated up to 100 DEG C and keep warm for 1 hour, then cool down to 40 DEG C, filter and dry to obta...

Embodiment 2

[0023] The preparation process is substantially the same as the method in Example 1, and the difference from Example 1 is that the frozen brine is cooled to 5-10°C, and the feeding amount of sodium nitrite is 242 kg (dry product, content ≥ 99%, 3.47Kmol) , 4 kilograms of sodium iodide and 8 kilograms of cuprous sulfate, the dropping temperature of diazonium solution and liquid sulfur dioxide is -10 ℃, the addition of liquid sulfur dioxide is 555 kilograms, obtains 2,2'-dithiosalicylic acid 441.4 kilograms , The yield in terms of anthranilic acid was 97.9%, and the purity was 98.1% by high performance liquid chromatography.

Embodiment 3

[0025] The preparation process is substantially the same as the method of Example 1, and the difference with Example 1 is that the charging capacity of sodium nitrite is 203 kilograms (dry product, content ≥ 99%, 2.91Kmol), 4.5 kilograms of potassium iodide and 8 kilograms of copper acetate , 278 kilograms of liquid sulfur dioxide to obtain 423.3 kilograms of 2,2'-dithiosalicylic acid, the yield in terms of anthranilic acid was 91.2%, and the purity was 95.3% through high performance liquid chromatography analysis.

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Abstract

The invention discloses a preparation method of 2,2'-dithio-salicylic acid shown as the formula I, and the method comprises the following steps: taking o-aminobenzoic acid as raw material, using sodium nitrite and hydrochloric acid for carrying out diazotization at the temperature of 0-10 DEG C, obtaining diazotized solution, leading the diazotized solution to be reacted with liquid sulfur dioxide for 0.5-3 hours at the temperature of minus 20-minus 10 DEG C in the presence of a catalyst and a co-catalyst, then keeping the temperature at 80-100 DEG C for 0.5-2 hours, cooling, filtering and obtaining the 2,2'-dithio-salicylic acid. The preparation method has the advantages of high reaction yield, good product purity, simple separation, a small amount of produced waste water, low productioncost and the like.

Description

(1) Technical field [0001] The present invention relates to a kind of preparation method of 2,2'-dithiosalicylic acid. (2) Background technology [0002] 2,2'-Dithiosalicylic acid, referred to as diacid, has a chemical structural formula as shown in formula I; molecular formula C 14 h 10 o 4 S 2 , molecular weight 306.06; CAS registration number 119-80-2; brown to off-white powder; melting point: 288-290 ° C; trade name: dithiosalicylic acid, dithiodibenzoic acid, DSTA, is a medicine, Important intermediates of dyes, fungicides BIT and photoinitiators ITX, etc., can be added to coatings and adhesives to improve mildew resistance; [0003] [0004] Chinese patent CN200510027679.4 reported that anthranilic acid was used as a raw material, and the target product was obtained by reacting with polysulfide after diazotization, with a yield of about 90%. This process will produce a large amount of difficult-to-treat sulfur-containing wastewater, causing great environmental ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C323/62C07C319/24
Inventor 贾建洪倪越彪孙炬晖高建荣
Owner 绍兴上虞洁源环保科技有限公司
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