Effects of pore structure of MgO-templated mesoporous carbon on its supported Pt catalysts for reductive alkylation of p-aminodiphenylamine with methyl isobutyl ketone

Abstract

Mesoporous carbon (MC) was prepared by the nano-MgO template method and used as a support for the preparation of a Pt-based reductive alkylation catalyst. N₂ physical adsorption–desorption, scanning electron microscopy, transmission electron microscopy and X-ray diffraction were used to characterize the carbon supports and supported Pt catalysts. The effects of the pore structure of the Pt/MC catalyst on its performance for reductive alkylation of p-aminodiphenylamine with methyl isobutyl ketone were investigated. The results show that the surface area and pore structure of the MgO-templated mesoporous carbons can be modulated directionally by varying the size of nano-MgO particles and the MgO/PF mass ratio. The catalytic activity and stability of the catalysts for N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine synthesis increases with an increase in the pore size of the mesoporous carbons. Complete conversion of p-ADPA and 100% selectivity to 6PPD were obtained over Pt/MC50(1/1) within 4 hours, which could maintain a high catalytic activity after being reused 10 times. The characterization results indicate that there was an obvious decrease in the BET specific surface area, pore volume and Pt specific surface area of all used catalysts compared with the fresh catalysts, and the trend was more obvious with the decrease of catalyst pore size, which should be the primary reason for the degradation of catalytic performance.