Preparation method of benzotriazole photostabilizer
A technology of benzotriazoles and light stabilizers, which is applied in the field of light stabilizer preparation, can solve the problems of explosion of benzotriazoles light stabilizers, unindustrial production, generation of toxic gases and the like, and achieves low preparation cost , the effect of high recovery rate and less side reactions
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Embodiment 1
[0027] Embodiment 1: the preparation method of a kind of benzotriazole light stabilizer of this example, its steps are:
[0028] a. 27.2g homemade 2-nitro-2′-hydroxyl-5′-methylazobenzene (94.5%), 10g sodium hydroxide and 120ml water were added to a 500ml three-necked flask, then 14g glucose was added to control the reaction temperature at 60 -70°C, reflux reaction for 2 hours, the solution turns light yellow after the reaction is completed. Slowly add 30% hydrochloric acid to neutralize the pH of the reaction solution to 6, a large amount of yellow precipitates are produced, filter, wash twice with 100ml water, and dry to obtain the intermediate 2-(2'-hydroxy-5'-methylphenyl)benzotri Azole nitrogen oxide 23.6g, yield is 97.9%;
[0029] b. Get the above-mentioned 2-(2′-hydroxyl-5′-methylphenyl) benzotriazole nitrogen oxide 23.6g, 12g sodium hydroxide, 0.5g catalyst, 80ml toluene and 60ml water join in the 500ml there-necked flask, Control the reaction temperature at 60-70°C...
Embodiment 2
[0030] Embodiment 2: the preparation method of a kind of benzotriazole light stabilizer of this example, its steps are:
[0031] a. 27.2g homemade 2-nitro-2′-hydroxyl-5′-methylazobenzene (94.5%), 8g sodium hydroxide and 120ml water were added to a 500ml three-necked flask, then 14g glucose was added to control the reaction temperature at 60 -70°C, reflux reaction for 2 hours, the solution turns light yellow after the reaction is completed. Slowly add 30% hydrochloric acid to neutralize the pH of the reaction solution to 6, a large amount of yellow precipitates are produced, filter, wash twice with 100ml water, and dry to obtain the intermediate 2-(2'-hydroxy-5'-methylphenyl)benzotri Azole nitrogen oxide 23.2g, yield is 96.3%;
[0032] b. Get the above-mentioned 2-(2′-hydroxyl-5′-methylphenyl) benzotriazole nitrogen oxide 23.2g, 10g sodium hydroxide, 0.5g catalyst, 80ml toluene and 50ml water join in the 500ml there-necked flask, Control the reaction temperature at 60-70°C,...
Embodiment 3
[0033] Embodiment 3: the preparation method of a kind of benzotriazole light stabilizer of this example, its steps are:
[0034] a. Add 35.4g of homemade 2-nitro-4-chloro-2′-hydroxy-3′-tert-butyl-5′-methylazobenzene (98.1%), 16g of sodium hydroxide, 180ml of methanol and 50ml of water into a 500ml three-port Then add 12g of glucose into the flask, control the reaction temperature at 60-70°C, and reflux for 2 hours. After the reaction is completed, the solution turns light yellow. Slowly add 30% hydrochloric acid to neutralize the pH of the reaction solution to 6, resulting in a large amount of yellow precipitate, filter, wash twice with 100ml water, and dry to obtain the intermediate 2-(2'-hydroxy-3'-tert-butyl-5' -Methylphenyl)-5-chlorobenzotriazole nitrogen oxide 31.8g, yield is 95.9%;
[0035] b. Take 31.8g of 2-(2'-hydroxyl-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole nitrogen oxide prepared above, 20g sodium hydroxide, 0.5g catalyst , Add 50ml of toluene and 1...
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