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Poly-halogenated benzoic acid synthesizing method

A technology of polyhalogenated benzoic acid and halogenated benzoic acid is applied in the directions of organic chemical methods, chemical instruments and methods, organic halogenation, etc., and can solve problems such as unfavorable industrialized production, environmental pollution, environmental pollution, etc., and achieve cost saving of raw materials , the effect of shortening the reaction time and reducing the production cost

Active Publication Date: 2014-05-07
ZHEJIANG LUOXING IND CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0018] The synthetic method of this type of compound has been reported, and US5013866 adopts bromine and salicylic acid to react in methanol to generate 3,5-dibromosalicylic acid. In the reaction process, 2 times the molar amount of bromine is used, and the cost is higher. And in the reaction process, hydrogen bromide gas is released, which pollutes the environment; in 2002, Li Hui et al. adopted salicylic acid and iodine chloride as raw materials in "3,5-diiodosalicylic acid synthesis new technology", and hydrochloric acid was Solvent synthesis of 3,5-diiodosalicylic acid also produces hydrogen chloride gas in the reaction, which also pollutes the environment. In addition, the cost is higher due to the use of more expensive iodine chloride; 3,5-Diiodosalicylic Acid and Green Synthesis of Acyl Chlorides" uses hydrogen peroxide and iodine to react in ethanol to generate 3,5-diiodosalicylic acid. Chlorobenzene or ethanol is used as a solvent in the reaction process, and the amount used is relatively high. Large, the cost is still high when enlarging the production
[0019] Among the reported synthetic methods, the method of using excessive halogen as halogenating reagent or using inorganic acid as solvent has the disadvantage of releasing toxic gases such as hydrogen bromide or hydrogen chloride in the reaction process, which causes great pollution to the environment; Iodine is used as an iodination reagent, or the method of using a large amount of organic solvents as a reaction medium also has the disadvantages of environmental pollution and high cost; it is not conducive to industrial production

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0039] Example 1: Into a 2L four-neck round bottom flask equipped with mechanical stirring, thermometer and condenser, 138.1g (1.00mol) of salicylic acid, 163.9g (1.03mol) of bromine, 7g (0.04 mol) was dissolved in methanol (500ml), stirred and heated to 45°C, 175g (1.5mol) of 30% hydrogen peroxide was added dropwise, the temperature was controlled at 55-60°C, and the dropping time was 1 hour. After dripping, keep it at 65°C for 4 hours. Then 500 g of water was added, the water bath was lowered to room temperature, filtered, and dried to obtain 277.6 g of 3,5-dibromosalicylic acid, with a yield of 93.8%. Melting point 224-226°C; 1 H NMR(DMSO-d 6 , 400MHz): δ 7.79 (d, J=2.4 Hz, 1H, ArH), 7.94 (d, J=2.4 Hz, 1H, ArH), 10.36 (s, 1H, OH).

Embodiment 2

[0040] Example 2: In a 2L four-neck round bottom flask equipped with mechanical stirring, thermometer and condenser, 138.1g (1.00mol) of salicylic acid, 261.4g (1.03mol) of iodine and 7g (0.04mol) of trichloroacetic acid were added Dissolve in methanol (500ml), stir and raise the temperature to 45°C, add 175g (1.5mol) of 30wt% hydrogen peroxide dropwise, control the temperature during the dropping at 60-65°C, and the dropping time for 1 hour. After dripping, keep it at 66°C for 5 hours. 500 g of water was added, the water bath was lowered to room temperature, filtered and dried to obtain 374.1 g of 3,5-diiodosalicylic acid, with a yield of 95.9%. Melting point: 233-235℃; 1 H NMR(DMSO-d 6 , 400MHz): δ 8.024 (d, J=2.4 Hz, 1H, ArH), 8.238 (d, J=2.4 Hz, 1H, ArH).

Embodiment 3

[0041] Example 3: In a 2L four-necked round bottom flask equipped with mechanical stirring, thermometer and condenser, 137.1g (1.00mol) of 2-aminobenzoic acid, 261.4g (1.03mol) of iodine, 7g (0.04 mol) was dissolved in methanol (500ml), stirred and heated to 45°C, 175g (1.5mol) of 30wt% hydrogen peroxide was added dropwise, the temperature was controlled at 60-65°C, and the dropping time was 1 hour. After dripping, keep it at 68°C for 5 hours. 500 g of water was added, the water bath was lowered to room temperature, filtered and dried to obtain 350.7 g of 2-amino-3,5-diiodobenzoic acid with a yield of 90.2%. Melting point: 232-234°C; 1 H NMR(DMSO-d 6 , 400MHz): δ 6.31 (s, 2H, NH2), 7.87 (d, J=2.4 Hz, 1H, ArM), 8.06 (d, J=2.4 Hz, 1H, ArH).

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Abstract

The invention provides a poly-halogenated benzoic acid synthesizing method. The method comprises the following steps: dissolving substituted benzoic acid, halogen and organic strong acid in a polar solvent for increasing temperature, after oxidation at a temperature of 50-70 DEG C, performing heat preservation at the temperature of 60-80 DEG C for 2-6 h, adding a right amount of water, and cooling to a room temperature, so as to obtain poly-halogenated benzoic acid. According to the invention, synthetic reaction is performed in an alcohols solvent, the halogen simple substance is used as a halogenating reagent, a small amount of organic strong acid is added, used as a catalyst, and used for catalyzing the electrophilic substitution reaction of the halogen to benzene rings, and hydrogen peroxide is dropwise added during the reaction to enable the halogen simple substance in the reaction system to be oxidized into halide ions so as to improve the utilization rate of the halogen and achieve the effect of atom economy.

Description

Technical field [0001] The invention relates to the field of chemical engineering, and in particular to a method for synthesizing polyhalogenated benzoic acid, which is prepared by using cheap and easily available substituted benzoic acid with electron-donating groups at the ortho position as raw materials. Background technique [0002] Polyhalogenated benzoic acid compounds are important intermediates in medicinal chemistry. Take 3,5-diiodosalicylic acid as an example, its global demand is more than 20,000 tons, which can be directly used as an iodine source in animal food; it is also a chemical fine product such as synthetic pesticides, medicines, veterinary drugs, flavors, and fragrances. It is an important intermediate for veterinary drugs, iodoether thiamine and cyliosamide. For its application fields, such as: 1) Iodoether thiamine, its structure is as follows: [0003] [0004] Structural formula 1 [0005] Iodosalamide is a halogenated salicylanilide trematocide. It is a s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07B39/00C07C51/363C07C65/05C07C229/56C07C227/16C07C323/62C07C319/12C07C65/21C07C63/70
Inventor 蓝玉明李佶辉常东亮
Owner ZHEJIANG LUOXING IND CO LTD
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