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Preparation method of benzotriazole ultraviolet absorbent

A benzotriazole and ultraviolet technology, applied in organic chemistry and other directions, can solve the problems of waste water pollution, environmental pollution, skin irritation, etc., to improve product purity and yield, reduce production costs, and avoid environmental pollution. Effect

Active Publication Date: 2015-06-17
ZHEJIANG CHANGSHAN KERUN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, wastewater pollution is more serious
(2) Hydrazine hydrate reduction method, the reaction itself generates water and nitrogen, which will not pollute the environment, but due to the high production cost, it is limited in industrial production
The disadvantage is that the reaction time is long, the amount of hydrogen transfer agent is large, and it cannot be reused, the cost is high, and the quinone irritates the skin, which will cause rash
(5) Yeast-NaOH reduction method, due to the large amount of yeast and ethanol, is not suitable for industrial production
(6) SmI 2 The reduction method uses THF as the solvent and uses SmI 2 The method for reducing o-nitroazobenzene to synthesize benzotriazole compounds, due to reducing agent Sml 2 The amount of solvent THF is too large, and SmI 2 Expensive, cost too much
(7) The electroreduction method requires a special electrolysis device, which is not practical for large-scale production
In a word, the reducing agent used in the above method is either costly or environmentally polluting.

Method used

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  • Preparation method of benzotriazole ultraviolet absorbent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Example 1 Synthesis of 2-(2'-hydroxy-3', 5'-di-tert-butylphenyl)-5-chlorobenzotriazole

[0022] 39 grams (0.1 mol) of 2-nitro-4-chloro-2'-hydroxyl-3', 5'-di-tert-butylazobenzene, 293 grams of 15% sodium hydroxide aqueous solution (containing 1.1 mol), 100 grams of toluene, and 100 grams of butanol were added to the reaction flask, stirred to disperse the solids evenly, continued to add 84 grams (0.8 moles) of sodium bisulfite under constant stirring, and then added 7.2 grams of aluminum powder in three batches (0.27 mole), follow the reaction by HPLC at 65°C for 5 hours, filter after the reaction, the filtrate is neutralized to neutral with 20% hydrochloric acid, filter, stand for layers, separate the water layer, and then use saturated salt for the organic layer Washed with water, separated to remove the brine layer, the remaining part was cooled and crystallized, filtered, and the filter cake was dried to obtain 28 grams of the product, the yield was 78%, the melting ...

Embodiment 2

[0023] Example 2 Synthesis of 2-(2'-hydroxyl-3', 5'-di-tert-butylphenyl)-5-chlorobenzotriazole

[0024] 39 grams (0.1 moles) of 2-nitro-4-chloro-2'-hydroxyl-3', 5'-di-tert-butylazobenzene, 240 grams of 20% aqueous sodium hydroxide (containing 1.2 mol), 85 grams of toluene, and 85 grams of butanol were added to the reaction flask, stirred to disperse the solids evenly, continued to add 124.8 grams (1.2 moles) of sodium bisulfite under constant stirring, and then added 10.8 grams of aluminum powder in three batches (0.4 mole), followed by HPLC at 60°C for 1 hour, filtered after the reaction, the filtrate was neutralized to neutral with 20% hydrochloric acid, filtered, allowed to stand for layers, and the water layer was separated, and the organic layer was washed with saturated salt Wash with water, remove the brine layer, cool and crystallize the remaining part, filter, and dry the filter cake to obtain 28.9 g of the product, with a yield of 81% and a melting point of 152-155°C...

Embodiment 3

[0025] Example 3 Synthesis of 2-(2'-hydroxyl-5'-methylphenyl)triazole

[0026]25.7 grams (0.1 moles) of 2-nitro-2'-hydroxy-5'-methylazobenzene, 480 grams of 10% aqueous sodium hydroxide solution (containing 1.2 moles of sodium hydroxide), 150 grams of toluene, butanol Add 150 grams into the reaction bottle, stir to disperse the solids evenly, continue to add 124.8 grams (1.2 moles) of sodium bisulfite under continuous stirring, then add 8 grams (0.3 moles) of aluminum powder in three batches, and pass through the HPLC followed the reaction for 3 hours, filtered after the reaction, the filtrate was neutralized to neutral with 20% hydrochloric acid, filtered, left to stand for stratification, and the water layer was separated, and the organic layer was washed with saturated brine, and the brine layer was separated, and the remaining Partially cooled and crystallized, filtered, and the filter cake was dried to obtain 18 g of the product, with a yield of 80% and a melting point of...

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Abstract

The invention discloses a preparation method of a benzotriazole ultraviolet absorbent shown as a formula (II). The method comprises the following steps of: adding an azo intermediate shown as a formula (I), sodium hydroxide aqueous solution, methylbenzene and butyl alcohol into a reactor, stirring to disperse the solid substances evenly, then, adding sodium hydrogen sulfite while stirring, adding aluminum powder in batches, heating up to 50-75 DEG C, reacting for 1-5 hours, tracking through HPLC (High Performance Liquid Chromatography), and after reaction, performing aftertreatment to obtain the benzotriazole ultraviolet absorbent shown as the formula (II). The method has the following beneficial effects that aluminum powder and sodium hydrogen sulfite are used as the reducing agent, the defect that sodium hydrosulfite is likely to decompose in the reducing process is solved, environment pollution caused by application of the redox systems, such as zinc powder, is avoided, meanwhile, purity and yield of products are improved, and production cost is lowered.

Description

(1) Technical field [0001] The invention relates to a preparation method of a benzotriazole ultraviolet absorber. (2) Background technology [0002] Benzotriazole compounds are the most productive and most diverse class of UV absorbers. They are a class of organic compounds that can selectively and strongly absorb solar ultraviolet rays that are harmful to polymers and have high light resistance. This kind of ultraviolet absorber has a higher absorption index in the range of 300-385nm, which is close to the requirement of ideal absorber. Since the 1970s, benzotriazole has been listed by Ciba-Geigy in Switzerland. Due to its oil resistance, discoloration resistance, low volatility, and good compatibility with polymers, it is widely used in various synthetic materials and products. Especially in automotive coatings it is the most commonly used and most effective UV absorber. As the application fields of engineering and modified plastics continue to expand, there is demand an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D249/20
Inventor 裴文何火雷郑红朝林士国
Owner ZHEJIANG CHANGSHAN KERUN CHEM