Preparation of Pt/Al2O3 catalyst in CTAB microemulsion and kinetics of m-chloronitrobenzene hydrogenation

Pt/Al₂O₃ catalyst was prepared successfully by a microemulsion method using cetyltrimethylammonium bromide (CTAB) as the surfactant and N₂H₅OH as the reducing agent. Selective hydrogenation of m-chloronitrobenzene (m-CNB) was used as a probe to investigate how parameters affect the preparation of catalysts via the microemulsion method. Transmission electron microscope (TEM) and selected-area electron diffraction (SAED) show that Pt particles (mean size 3 nm) were distributed uniformly on the catalyst and were in polycrystalline structure. Experiments on m-CNB selective hydrogenation show that at 303 K and hydrogen pressure of 0.1 MPa, the turnover frequency (TOF) was 0.216 s^–1, the m-CNB conversion was 99.6% and the m-CAN selectivity was 98.9%, indicating high dechlorination inhibition effect. The reaction was an approximately first-order process with apparent activation energy of 26.92 kJ mol^–1.