background and overview[1]
uv absorber uv-329, namely 2-(2′-hydroxy-5′-teroctylphenyl) benzotriazole, is a high-efficiency anti-aging additive with excellent performance, soluble in benzene and styrene , methylene chloride and cyclohexane, slightly soluble in alcohols and insoluble in water; can effectively absorb ultraviolet light of 270-380 nanometers; non-flammable, non-explosive, non-toxic, safe and harmless to use; widely used in pe, pvc, pp, ps, pc, polypropylene fiber, abs resin, epoxy resin, resin fiber and ethylene vinyl acetate, etc., and can be used in packaging materials such as plastic containers and food packaging boxes, providing them with good light stabilization effects , almost no visible light absorption, especially suitable for colorless, transparent and light-colored products.
preparation[1-2]
report 1,
preparation of 2-(2′-hydroxy-5′-teroctylphenyl)benzo from o-nitrochlorobenzene through amination, diazotization, coupling, one-step reduction, two-step reduction reaction and post-treatment process triazole products.
step 1. preparation of 2-nitroaniline: pour 1 mol of 2-nitrochlorobenzene and 20 mol of 20% ammonia into a pipeline ammonia reactor for ammoniation at 150~220°c and 12~20mpa react for 30 to 50 minutes. the remaining ammonia in the system is sprayed to circulate and absorb the low-concentration ammonia water produced. after adding part of the liquid ammonia, it continues to be used for the ammoniation reaction. the deamination material is separated by layering and static separation to remove ammonium chloride. (use lime water to neutralize and recover ammonia), and obtain 2-nitroaniline product through cooling and crystallization, with a yield of ≥98.6% and a purity of ≥99.6%.
step 2, preparation of 2-nitrodiazophenyl hydrochloride: add 1 mol of 2-nitroaniline, 3 to 4 mol of 31% hydrochloric acid and 500 ml of water into the diazotization reaction kettle, stir and cool to below 10°c, add 1.0 to 1.2 mol of 30% nano2 aqueous solution, insulate and react for 60 minutes, add a small amount of urea to terminate the reaction, and filter. the resulting filtrate is 2-nitrodiazophenyl salt. salt solution.
step 3. preparation of 2-nitro-2′-hydroxy-5′-teroctyl azobenzene: add 1 mol of 4-teroctylphenol and 1500 ml of ethanol into the coupling reaction kettle, stir and dissolve, cool to below 10°c, adjust the ph to weak alkalinity with 15% alkaline substance aqueous solution (the optimal ph is 7.2-7.8), add 2-nitrodiazophenyl hydrochloride solution dropwise under temperature control, and react for 3 hours. filter with suction, wash the filter cake with a small amount of ethanol, and dry to obtain 2-nitro-2′-hydroxy-5′-teroctylazobenzene, with a yield of ≥93% and a purity of ≥98%.
step 4, preparation of 2-(2′-hydroxy-5′-teroctylphenyl) benzotriazole nitrogen oxide: add 1 mol of 2-nitro-2′-hydroxy-5′-ter add octyl azobenzene, 15 mol of reducing agent (the molar ratio of methanol and formaldehyde is 3:1), and 1.2 mol of sodium hydroxide into the one-step reduction reaction kettle, raise the temperature to reflux, react for about 6 to 12 hours until the reaction is completed, and cool 25℃~35℃, adjust the ph to 3 with 30% hydrochloric acid, filter, wash the filter cake with water, and drain it. the filter cake is 2-(2′-hydroxy-5′-teroctylphenyl) benzotriazole. nitrogen oxides.
step 5, preparation of 2-(2′-hydroxy-5′-teroctylphenyl)benzotriazole: add 1 mol of 2-(2′-hydroxy-5′-teroctylphenyl) benzotriazole nitrogen oxide, 3.4 mol of 30% hydrochloric acid, 0.5 mol of zinc powder and 1500 ml of toluene were added to the two-step reduction kettle, heated to reflux, reacted for 2 to 6 hours until the reaction was completed, filtered to remove the zinc powder, and the filtrate was washed with water until center, cool and crystallize, filter, the filter cake is recrystallized with dichloromethane and cyclohexane, filter, the filtrate is recovered and used in dichloromethane and cyclohexane, and the ultraviolet absorber uv-329 is obtained after the filter cake is dried.
report 2,
step 1: combine homemade 2-nitro-2′-hydroxy-5′-tert-octyl azobenzene (97.8%), 36.3g (0.1021mol), 10g sodium hydroxide, 250ml methanol and 50ml water , added to a 500ml four-necked flask, controlled the reaction temperature at 64°c and slowly added 6.34g of the reducing agent prepared according to example 1, and refluxed for 2 hours. the end point of the reaction was when the solution turned light yellow;
step 2: slowly add 30% hydrochloric acid dropwise, neutralize the reaction solution to a ph of 6, and produce a large amount of yellow precipitate. filter, wash twice with 50 ml of water, and dry to obtain the intermediate 2-(2′-hydroxy-5 ‘-tert-octylphenyl) benzotriazole nitrogen oxide 31.6g, yield 93.2%;
step 3: take 31.6g (0.0977mol) of 2-(2′-hydroxy-5′-tert-octylphenyl)benzotriazole nitrogen oxide obtained in the previous step, 20ml of 98% sulfuric acid, 120ml of toluene and add 60 ml of water to a 500 ml four-necked flask, control the reaction temperature at 64°c and slowly add 5.79 g of the reducing agent prepared according to example 1, and reflux for 2 hours. the end point of the reaction is when the solution turns into light yellow-green;
step 4: filter the solution to remove insoluble matter first, pour the filtrate into 100ml of water, cool and crystallize, filter, wash twice with 50ml of water, and dry to obtain the product uv absorber uv-32927.8g, with a yield of 86.1%. the melting point is 103-105℃.
references
[1] [chinese invention] cn201910455652.7 preparation method of ultraviolet absorber uv-329
[2] [chinese invention, chinese invention authorization] cn201610346337.7 preparation method of ultraviolet absorber uv-329