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The Synthesis of a New Benzotriazole Ultraviolet Absorber

Author: AiWen
Tutor: WangShiSheng；LuYueJin
School: Dalian University of Technology
Course: Pharmaceutical Engineering
Keywords: 4-tert-octylphenyl azo dye benzotriazole ultraviolet disoxidation
CLC: TQ424
Type: Master's thesis
Year: 2008
Downloads: 381
Quote: 1
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Abstract

The benzotrazole ultraviolet absorbers are widely used in industry for the protection of commercially important synthetic fibres,plastics and coatings against light.As the rapid development of application,the demand for clean and‘green’ chemical synthesis has been growing,New preparation techniques for the preparation of ultraviolet absorbers have been paid more and more attention.In this paper,the benzotriazole ultraviolet absorbers and its intermediate were synthesized according to commercial application and environment protection.The 2-cumenyl-4-tert-octylphenyl was synthesized from 4-tert-octylphenyl andα-metylphenylethylene with aluminum phenate as catalystst.Several factors such as material proportion,dropwise time,reaction temperature and the amount of aluminum dust were discussed.The yield of the product was 90.5%and the purity was upto 99.8%(by GC). The product was charactersed by UV-Vis,~1H-NMR,IR,MS,element analysis and melting point.The 2-nitro-2′-hydroxy-3′-cumenyl-5′-tert-octylphenyl-azobenzene was synthesized from o-nitro-aminobenzene,sodium nitrite and 2-cumenyl-4-tert-octylphenyl.Several factors such as material proportion and reaction time were discussed.The yield of the product was 88.1% and the purity was upto 99.5%(by HPLC).The product was charactersed by UV-Vis, ~1H-NMR,IR,MS,elemental analysis and melting point.The same intermediate was synthesized from the solid phase reaction.Several factors such as reaction time and the amount of acid were discussed.which gave the product in 60.78%.The different factors such as reaction time and the amount of acid were discussed. The yield of the product was 60.78%and the purity was upto 99.5%(by HPLC).The main advantages of this method are clean,rapid reaction rate and convenient for industrial production.2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole was synthesized by the intermediate with zinc dust as reduction agent,.The compound was charactersed by UV-Vis, ~1H-NMR,IR,MS and element analysis.The factors which effect the reaction yield and quality were studied.Under the optimum conditions,the UV-Visible absorption capacity of this product was superior,the transmittance at wavelengths of 500nm is higher than 99.4% and ash content is lower than 0.008%.In this method the yield was 62%and the quality was 99.4%. 2-nitro-2′-hydroxy-3′-cumenyl-5’-tert-octylphenyl-azobenzene was reduced to ultraviolet absorbers with Raney-Ni as catalyst.The factors such as the kinds of catalyst,temperature, pressure and the amount of catalyst were studied.The yield was 72.2%and the quality was 99.5%under the optional conditions.The advantage of this method is green.One kettle method is another way to get the product.The yield was attained 72.5%and the purity was 99.5%.The method has lots of advantages such as simple manipulation,minor liquid waste and higher yield.

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