微乳液法制备Pt/Al2O3催化剂及其催化氯代硝基苯选择加氢活性

采用十六烷基三甲基溴化铵（CTAB）/正丁醇/环己烷/H₂PtCl₆溶液的微乳体系，以N₂H₄·H₂O为还原剂，Al₂O₃为载体制备Pt/Al₂O₃催化剂。以邻氯硝基苯（o-CNB）选择加氢反应为探针，考察微乳液组成对Pt/Al₂O₃催化剂选择加氢活性的影响。运用XRD、XPS、IR、TEM和EDS对载体和催化剂进行表征。结果表明，微乳体系中CTAB∶正丁醇∶环己烷质量比9∶21∶70，3.6% H₂PtCl₆溶液中制备的Pt/Al₂O₃催化剂的o-CNB选择加氢活性最高。Pt粒子粒径5 nm左右，与载体之间没有明显的电子效应。对于取代位置不同的间、对氯硝基苯（m-CNB、p-CNB）加氢，Pt/Al₂O₃催化剂也表现出较高的催化活性。

Preparation of Pt/Al2O3 catalyst by microemulsion and its activity in selective hydrogenation of chloronitrobenzene

Pt/Al₂O₃ catalyst was prepared from CTAB/butarol/cyclohexane/H₂PtCl₆ microemulsion，with hydrazine as reductant and Al₂O₃ as support. The effect of composition of microemulsion on the activity for selective hydrogenation over Pt/Al₂O₃ catalysts was studied by using o-chloronitrobenzene selective hydrogenation as a probe reaction. The support and catalyst were characterized by XRD，XPS，IR，TEM and EDS.  The results showed that the Pt/Al₂O₃ catalyst made from the microemulsion with CTAB：butarol：cyclohexane mass ratio of 9∶21∶70 and H₂PtCl₆ concentration of 3.6% exhibited the highest activity in selective hydrogenation of o-CNB. Pt particle size was about 5 nm，and the electronic effect between Pt particle and carrier was not significant. It was also found that Pt/Al₂O₃ catalyst also exhibited higher activity for the hydrogenation of m-chloronitrobenzene and p-chloronitrobenzene with different substituted positions.