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Preparation method of ultraviolet light absorber 2-phenylbenzimidazole

A technology of phenylbenzimidazole and absorbent, which is applied in the field of preparation of ultraviolet absorbent 2-phenylbenzimidazole, can solve the problems of polluted environment, low product yield, large amount of waste acid, etc., and achieves simplified preparation process, reduce the temperature of sulfonation reaction, and ensure the effect of high purity

Inactive Publication Date: 2020-04-10
HUANGGANG MEIFENG CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to overcome the above-mentioned deficiency of prior art, the present invention proposes a kind of preparation method of ultraviolet absorber 2-phenylbenzimidazole, solves existing ultraviolet absorber 2-phenylbenzimidazole-5-sulfonic acid preparation existing problem Technical problems such as low product yield, large amount of waste acid and environmental pollution

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  • Preparation method of ultraviolet light absorber 2-phenylbenzimidazole
  • Preparation method of ultraviolet light absorber 2-phenylbenzimidazole

Examples

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Effect test

Embodiment 1

[0028] Such as figure 1 Shown, a kind of preparation method of ultraviolet absorber 2-phenylbenzimidazoles specifically comprises the following steps: 157g (1.35mol) chlorosulfonic acid is slowly dripped in the sulfuric acid of 180g98% in stirring, mix uniformly and set aside. Put 194g (1.0mol) of 2-phenylbenzimidazole and 1000g of dichloroethane into a 2L reaction flask, stir and raise the temperature to 75°C, drop the above-mentioned mixed acid into the reaction flask for reaction, and the dropping time is 3 hours. After the dropwise addition, continue the insulation reaction for 3 hours, and absorb the hydrogen chloride gas produced in the reaction process with lye.

[0029] After the reaction, stop stirring and let it stand for stratification. The light yellow solution in the upper layer is dichloroethane, which can be directly used in the next batch of reactions without distillation to make up the lost amount. The dark liquid in the lower layer was dropped into 2000L of ...

Embodiment 2

[0032] Slowly drop 140g (1.2mol) of chlorosulfonic acid into 200g of 100% sulfuric acid under stirring, mix well and set aside. Put 194g (1.0mol) of 2-phenylbenzimidazole and 1000g of dichloroethane into a 2L reaction flask, stir and raise the temperature to 76°C, drop the above-mentioned mixed acid into the reaction flask for reaction, and the dropping time is 3 hours. After the dropwise addition, continue the insulation reaction for 3 hours, and absorb the hydrogen chloride gas produced in the reaction process with lye.

[0033] After the reaction, stop stirring and let it stand for stratification. The light yellow solution in the upper layer is dichloroethane, which can be directly used in the next batch of reactions without distillation to make up the lost amount. The dark liquid in the lower layer was dropped into 2000L of vigorously stirred water, and the hydrolysis temperature was controlled at 10°C. After separation by filtration, the obtained white solid is the crude...

Embodiment 3

[0036] Put 194g (1.0mol) of 2-phenylbenzimidazole, 900g of dichloroethane recovered by layering in the previous batch, 100g of fresh dichloroethane, and 180g of 98% sulfuric acid into a 2L reaction flask, and stir to raise the temperature to 77°C. Take by weighing 163g (1.4mol) chlorosulfonic acid, drop in the reaction flask and react, the dropwise addition time is 3 hours, continue insulation reaction for 3 hours after dropwise addition, absorb the hydrogen chloride gas that reaction process produces with lye.

[0037] After the reaction, stop stirring and let it stand for stratification. The light yellow solution in the upper layer is dichloroethane, which can be directly used in the next batch of reactions without distillation to make up the lost amount. The dark liquid in the lower layer was dropped into 2000L of vigorously stirred water, and the hydrolysis temperature was controlled at 20°C. After separation by filtration, the obtained white solid is the crude product of ...

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Abstract

The invention relates to a preparation method of ultraviolet light absorber 2-phenylbenzimidazole, which specifically comprises the following steps: S1, adding 2-phenylbenzimidazole and an organic solvent into a reaction vessel, adding a composite sulfonating agent while stirring, and sufficiently reacting; S2, standing and layering a product obtained by sulfonation reaction in S1, stirring and quenching a lower-layer solution, separating out a solid, and carrying out solid-liquid separation to obtain a 2-phenylbenzimidazole-5-sulfonic acid crude product; recycling the organic solvent in the upper layer; and S3, putting the crude product obtained in the S2 into water, adjusting the pH value while stirring to fully dissolve the 2-phenylbenzimidazole-5-sulfonic acid crude product, adding activated carbon, stirring for decolorization, filtering, adding an acid into a filtered clarified solution for acidification, separating out a solid, carrying out solid-liquid separation, and drying toobtain the 2-phenylbenzimidazole-5-sulfonic acid refined product. By the adoption of the preparation method, the obtained product is high in purity and good in quality, meanwhile, the waste acid generation amount is small, a pure white product can be obtained through one-time refining, and the process is simplified.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a preparation method of ultraviolet absorber 2-phenylbenzimidazole. Background technique [0002] UV absorber 2-phenylbenzimidazole-5-sulfonic acid, the English name is 2-phenylbenzimidazole-5-sulfonic acid, and the English abbreviation is PBSA or PSA. It is a water-soluble UV absorber with low toxicity and irritation Small, strong UV absorption and other characteristics, mainly used in cosmetics and water-based paints. [0003] At present, the synthesis methods of 2-phenylbenzimidazole-5-sulfonic acid reported at home and abroad mainly include the following types. [0004] It is reported in US5473079 to use o-phenylenediamine, benzoic acid and excess sulfuric acid to obtain 2-phenylbenzimidazole-5-sulfonic acid in one pot. The reaction needs to be heated to 178 °C in the presence of a large amount of sulfuric acid. The raw materials are easy to However, the preparation conditi...

Claims

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Application Information

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IPC IPC(8): C07D235/18
CPCC07D235/18
Inventor 徐文立刘建军曾诚洪浩曹瑜吴炜
Owner HUANGGANG MEIFENG CHEM TECH
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