Mechanistic Insights on the Functionalization of CO
<sub>2</sub>
with Amines and Hydrosilanes Catalyzed by a Zwitterionic Iridium Carboxylate‐Functionalized Bis‐NHC Catalyst
作者:Ana I. Ojeda‐Amador、Julen Munarriz、Pablo Alamán‐Valtierra、Víctor Polo、Raquel Puerta‐Oteo、M. Victoria Jiménez、Francisco J. Fernández‐Alvarez、Jesús J. Pérez‐Torrente
DOI:10.1002/cctc.201901687
日期:2019.11.21
pressure (3 bar) the formamide derivative was obtained as major reaction product. The unexpected formation of pyrrolidin‐1‐ium formate as intermediate of the reaction the 1‐catalyzed of CO2 with pyrrolidine and HSiMe2Ph has been observed, and its role in the formation of 1‐formylpyrrolidine rationalized. Moreover, a mechanism for the reaction of CO2 with hydrosilanes, in the presence and in the absence
Preparation of protic ionic liquids with minimal water content and 15N NMR study of proton transfer
作者:Geoffrey L. Burrell、Iko M. Burgar、Frances Separovic、Noel F. Dunlop
DOI:10.1039/b921432a
日期:——
Low-molecular-weight Brønsted acids and amine bases were used to reproducibly prepare very dry, high-purity room-temperature protic ionic liquids (PILs). A series of eight amine bases and six Brønsted acids were combined to produce 48 mixtures, of which 18 were liquid at room temperature. The phase transitions and thermal decomposition temperatures were determined for each mixture; whereas viscosity, density and conductivity were determined for the room-temperature liquids. By utilising 15N NMR it was possible to distinguish between neutral and ionised amine bases (ammonia vs. ammonium-type ion), which indicated that the protic ionic liquids were completely ionised when made as a stoichiometric mixture. However, a Walden plot comparison of fluidity and molar conductivity indicated the majority of PILs had much lower conductivity than predicted by viscosity unless the base contained excess proton-donating groups. This disparity is indicative of protic ionic molecules forming neutral aggregates or non-Newtonian fluid hydrogen-bonded networks with a secondary Grotthuss proton-hopping mechanism arising from polyprotic bases.