Theoretical Study of the Catalytic Performance of Activated Layered Double Hydroxides in the Cyanoethylation of Alcohols

• Published in: Journal of physical chemistry. C 2019-04, Vol.123 (14), p.8777-8784
• Main Authors: Cuautli, Cristina, Valente, Jaime S, Conesa, J. C, Ganduglia-Pirovano, M. Verónica, Ireta, Joel
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.8b10935

The layered double hydroxides (LDHs) containing Mg2+, Al3+, and OH– (MgAl-OH), commonly known as meixnerite, meixnerite-like, or activated LDH, act as catalyst in the cyanoethylation of alcohols, for which the catalytic activity depends on the LDH composition, particularly on the ratio R between the amount of Mg2+ and Al3+. It is known that MgAl-OH with R = 3 presents the largest catalytic activity when the reactants are methanol and acrylonitrile. To determine the molecular basis of such behavior, the adsorption of OH–, CH3O–, and H2O on the (001) surfaces of MgAl-OH with compositions R = 2, 3, and 3.5 is investigated using density functional theory. It is found that the peculiar catalytic activity of MgAl-OH in the methanol cyanoethylation reaction correlates with the capability of the MgAl-OH surface to stabilize CH3O–a process in which hydrogen bonding plays a crucial roleand the reactivity of the adsorbed CH3O– lone pairs.