合成苯并三氮唑紫外吸收剂的加氢催化剂研究

Study on Hydrohenation Catalysts for Synthesis of Benzotriazole Ultraviolet Absorbers

摘要:

苯并三氮唑及其衍生物是一类毒性低、稳定性高且应用广泛的紫外吸收材料。文章研究了炭载PdPtCu三金属催化2-硝基-（2’-羟基-5’-甲基苯基）偶氮苯（HAB）加氢合成2-（2’-羟基-5’-甲基苯基）苯并三氮唑（UV-P）的性能，在323 K、0.5 MPa氢气压力条件下反应5 h后HAB转化率为100%、UV-P选择性达92.2%，实现了偶氮化合物加氢高选择性地合成苯并三氮唑紫外吸收剂的目的。利用XRD、TEM及XPS等催化剂表征手段，发现Cu-Pd、Cu-Pt合金相与催化剂表面适量的缺电子态贵金属物种(Mδ )可以有效抑制N-N键断裂与过度加氢副反应，降低了四氢化合物和芳胺类等副产物的生成。

Abstract:

Benzotriazole and its derivatives are widely used as UV absorbers, due to their low toxicity and excellent stability. The catalytic performance of PdPtCu/C for the synthesis of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole (UV-P) from 2-nitro- (2'-hydroxy-5'-methylphenyl) azobenzene (HAB) was studied. The conversion of HAB reached 100% and the selectivity of UV-P kept 92.2% after 5 h’ reaction at 323 K and 0.5 MPa hydrogen pressure. XRD, TEM and XPS results showed that the formation of Cu-Pd, Cu-Pt alloy phase and the proper amount of the noble metal species (Mδ ) on the surface of the catalyst were the key factors to inhibit the breakage of N-N bond and to reduce the by-reaction of excessive hydrogenation, which thereby supressed the formation of tetrahydrofins and aromatic amines by-products.