Renewable N-doped active carbons as efficient catalysts for direct synthesis of cyclic carbonates from epoxides and CO2

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Ajaikumar Samikannu, Lakhya Jyoti Konwar, Päivi Mäki-Arvela, Jyri-Pekka Mikkola
Publication year: 2019
Journal: Applied Catalysis B: Environmental
Journal acronym: Appl. Catal., B
Volume number: 241
Start page: 41
End page: 51
eISSN: 1873-3883


Abstract

In the spirit of green chemistry and greenhouse gas mitigation, we explore herein the chemical utilization of CO2 upon synthesis of cyclic carbonates over N-doped activated carbons. The N-doped carbocatalysts were obtained from inexpensive N-rich bio-waste precursors and characterized by standard techniques (N2 physisorption, chemisorption, XPS, SEM, TEM, XRD, FT-IR and Micro-Raman spectroscopy). The materials exhibited excellent catalytic activity for direct carbonation of epoxides with CO2 to cyclic carbonates (yields upto 99%) under solvent free, moderate temperature (100–150 °C) and low CO2 pressure (5–50 bar) conditions. The observed catalytic activity of the N-doped carbocatalysts was attributed to the Lewis basic sites originating from pyridinic, pyridonic, and quaternary N-sites capable of activating the CO2 molecule. While control experiments with multiwalled carbon nanotubes (MWCNT) or commercial activated carbon, failed to produce cyclic carbonates due to lack of active (basic) sites. In terms of the catalytic performance, the N-doped carbocatalysts presenting a high porosity (634–1316 m2/g) and high levels of pyridinic (33%) and quaternary N-doping (30%), (i.e. CA500 and MA500), exhibited the highest activity and selectivity (TOF, conversion and cyclic carbonate yields upto 99% in 5–15 h). Most importantly, these materials demonstrated good operational stability and reusability.


Keywords

Chemical Engineering

Last updated on 2019-14-12 at 03:00

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