One-Pot direct reductive amination of furfural over Pd@CNTs

N-substituted furfuryl amines (secondary amines) are important class of organic compounds which are primarily used in making agricultural and pharmaceutical intermediates. The main objective of the present study is to develop the use of bio-based ennvironment friendly chemical such as furfural for selective one-step process for N substituted furfuryl amines production using formic acid (FA) as a hydrogen source over heterogeneous catalyst. Rh-CNTs, Pd-CNTs, Pd-Al2O3, and Pd-HT catalysts were prepared using a facile combination of wet impregnation, followed by freeze-drying method and used for the synthesis of N-substituted furfuryl amines. The as synthesized and used catalysts were characterized by various physico-chemical characterization methods to investigate the role of support in promoting activity and selectivity of catalyst. Under optimised condition, PdCNTs catalyst in methanol was found to convert furfural and aniline almost completely to N-(furan-2-ylmethyl) aniline. Moreover, Pd-CNTs catalyst showed outstanding activity towards complete decomposition of FA to H2 and CO2, giving a high yield of N-(furan-2-ylmethyl)aniline (>99%) from hydrogenation of furfural and aniline. The catalyst also showed good recyclability and worked for at least three consecutive recycling runs without lossing activity. The effect of reaction parameters viz. temperature, reaction time, and FA concentration, on the conversion and selecivity were studied in detail.

Automated summary

This study aims to develop a new method for the production of N-substituted furfuryl amines using bio-based environmentally friendly chemicals. The results show that the PdCNTs catalyst, under optimized conditions, can convert furfural and aniline almost completely to N-(furan-2-ylmethyl) aniline in methanol, with a yield of over 99%. The catalyst also exhibits good recyclability.