Nature of active sites on UiO-66 and beneficial influence of water in the catalysis of Fischer esterification

michel — Mon, 13 Feb 2017 14:07:11 +0000

C. Caratelli, J. Hajek, F. G. Cirujano, M. Waroquier, F. X. Llabres i Xamena, V. Van Speybroeck

Journal of Catalysis

352, 401-414

2017

Abstract

Zirconium terephthalate UiO-66 type metal organic frameworks (MOFs) are known to be highly active, stable and reusable catalysts for the esterification of carboxylic acids with alcohols. Moreover, when defects are present in the structure of these MOFs, coordinatively unsaturated Zr ions with Lewis acid properties are created, which increase the catalytic activity of the resulting defective solids. In the present work, molecular modeling techniques combined with new experimental data on various defective hydrated and dehydrated materials allow to unravel the nature and role of defective active sites in the Fischer esterification and the role of coordinated water molecules to provide additional Brønsted sites. Periodic models of UiO-66 and UiO-66-NH2 catalysts have been used to unravel the reaction mechanism on hydrated and dehydrated materials. Various adsorption modes of water and methanol are investigated. The proposed mechanisms are in line with experimental observations that amino groups yield a reduction in the reaction barriers, although they have a passive role in modulating the electronic structure of the material. Water has a beneficial role on the reaction cycle by providing extra Brønsted sites and by providing stabilization for various intermediates through hydrogen bonds.

Open Access version available at UGent repository

Gold Open Access

DOI

http://dx.doi.org/10.1016/j.jcat.2017.06.014

Private attachment

1-s2.0-S002195171730221X-main-1.pdf

First principle study of active sites on UiO-66 for Fischer esterification

wim — Tue, 12 Sep 2017 07:43:18 +0000

C. Caratelli, J. Hajek, F. G. Cirujano, M. Waroquier, F.X. Llabres i Xamena, V. Van Speybroeck

ISBN/ISSN:

Talk

Conference / event / venue

Europacat 2017

Florence, Italy

Sunday, 27 August, 2017 to Thursday, 31 August, 2017

Conference reference

EUROPACAT 2017

First principle characterization of active sites on UiO-66 and their role in the catalysis of Fischer esterification

chiara — Tue, 25 Apr 2017 12:37:13 +0000

C. Caratelli, J. Hajek, F. G. Cirujano, M. Waroquier, F. X. Llabres i Xamena, V. Van Speybroeck

ISBN/ISSN:

Talk

Conference / event / venue

NCCC XVIII

Noordwijkerhout, The Netherlands

Sunday, 5 March, 2017 to Tuesday, 7 March, 2017

Center for Molecular Modeling - F. G. Cirujano

Nature of active sites on UiO-66 and beneficial influence of water in the catalysis of Fischer esterification

Abstract

DOI

Private attachment

First principle study of active sites on UiO-66 for Fischer esterification

Conference / event / venue

Conference reference

First principle characterization of active sites on UiO-66 and their role in the catalysis of Fischer esterification

Conference / event / venue