investigated the fixation of CO2 by several amidines in solution and found that simple monocyclic amidines fixed CO2 under dry conditions to quantitatively afford the corresponding bicarbonatesthrough hydrolysis of the zwitterionic adducts by adventitious water. In contrast, linear amidines did not form the bicarbonates under the same conditions, while 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) could not
A comparative solid state 13C NMR and thermal study of CO2 capture by amidines PMDBD and DBN
作者:Fernanda Stuani Pereira、Deuber Lincon da Silva Agostini、Rafael Dias do Espírito Santo、Eduardo Ribeiro deAzevedo、Tito José Bonagamba、Aldo Eloizo Job、Eduardo René Pérez González
DOI:10.1039/c1gc15457e
日期:——
The present work shows study of the CO2 capture by amidines DBN and PMDBD using 13C solid-state NMR and thermal techniques. The solid state 13C NMR analyses demonstrate the formation of a single PMDBD-CO2 product which was assigned to stable bicarbonate. In the case of DBN, it is shown that two DBN-CO2 products are formed, which are suggested to be stable bicarbonate and unstable carbamate. The role of water in the DBN-CO2 capture as well as the stability of the products to environmental moisture was also investigated. The results suggest that the carbamate formation is favored in dry DBN, but in the presence of water it decompose to form bicarbonate. Thermal analysis shows a good gravimetric CO2 absorption of DBN. Release of CO2 was found to be almost quantitative from the PMDBDH+ bicarbonate about 110 °C.
The transient carbonation of polyols under a CO2 atmosphere enables their C−H monoalkylation by photoredox catalysis. This reactivity results from an unprecedented C−H activation through intramolecular hydrogen bonding.