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2-(2,4-二羟基苯基)-5-磺酸基苯并三唑(DPSB)是新型活性紫外线吸收剂的重要中间体。以邻硝基苯胺、浓硫酸和间苯二酚为原料,经磺化、重氮化、偶合及还原环化四步反应制得2-(2,4-二羟基苯基)-5-磺酸基苯并三唑(DPSB),偶合产物4-((2,4-二羟基-苯基)偶氮基)-3-硝基苯磺酸(DPANB)和还原产物2-(2,4-二羟基苯基)-5-磺酸基苯并三唑(DPSB)的结构用IR、NMR、MS表征。探讨了偶合和还原反应中各项条件对反应产率的影响,偶合反应的优化条件为:n(间苯二酚)∶n(HCl)=1∶4时,在温度为0℃下反应3 h,产率为64.6%;还原反应的优化条件为:使用二氧化硫脲还原剂,在70℃反应1 h,产率为87.7%。该物质在波长300~385 nm范围内有较高的吸光指数,具有很好的紫外吸收性能,且水溶性得到很大提高。
2- (2,4-dihydroxyphenyl) -5-sulfobenzotriazole (DPSB) is an important intermediate of new active UV absorber. Using o-nitroaniline, concentrated sulfuric acid and resorcinol as raw materials, 2- (2,4-dihydroxyphenyl) -5-sulfonamide was obtained via four steps of sulfonation, diazotization, coupling and reductive cyclization (2,4-dihydroxy-phenyl) azo) -3-nitrobenzenesulfonic acid (DPANB) and the reduction product 2- (2,4 -dihydroxyphenyl) -5-sulfobenzotriazole (DPSB) was characterized by IR, NMR, MS. The effects of various conditions on the yield of the coupling reaction were discussed. The optimum conditions for the coupling reaction were as follows: reaction of n (resorcinol): n (HCl) = 1: 4 at 0 ℃ h, the yield was 64.6%. The optimum conditions for the reduction reaction were as follows: the reaction was carried out at 70 ℃ for 1 h with a thiourea dioxide reductant, the yield was 87.7%. The material in the wavelength of 300 ~ 385 nm range has a high absorption index, has good UV absorption properties, and water-soluble greatly improved.