Gallosilicate catalysts: from a sustainable synthesis toward the efficient conversion of crude glycerol

A. Maertens1, A. Vivian1, L. Fusaro1, M. Armandi2, S. Fiorilli2, C. Aprile1*

1Unité de chimie des nanomatériaux, Département de Chimie, Université de Namur,
Departement of Applied Science and Technology, Politecnico di Turino

Heterogeneous catalysis has become essential in our modern industrial world as around 70% of all industrial processes require the use of solid catalyst.1 In the field of acid catalysis, the great perspectives brought by silica based mesoporous materials bearing trivalent element (e.g. Al2, Ga3) as single site are no longer to be proven. Recently, we reported the preparation of extra-small (<100nm) silica nanospheres (NS) obtained via a rapid synthesis protocol (30 min) in aqueous medium without additional hydrothermal treatment.4 Such reaction parameters are particularly interesting to minimize the environmental impact of the synthesis.

In this work, we propose the optimization of the synthesis of SiO2 NS bearing Ga as single sites. Both Brønsted and Lewis acidity are introduced via the presence of Ga which is highly beneficial for the targeted reaction (i.e. acetylation of glycerol with acetone) as observed by the high activity of all the materials. The influence of the Ga loading on the catalysts performance was assessed by confronting catalytic activity with advanced characterization techniques (e.g. IR of probe molecules, 71Ga MAS NMR (Fig. 1a)). To go forward in the sustainability of the process, the activity of the material in presence of the main impurities of crude glycerol was investigated and the best material was still very active and selective
(Fig 1b). Its activity was further improved via the surface functionalization with fluorine moieties.


1. Thomas, J. M., Harris, K. D. M., Energy & Environmental Science, 2016, 9, 687-708.
2. Corma, A., Chem Rev, 1997, 97, 2373-2420.

3. Vivian, A., Soumoy, L., Fusaro, L., Louette, P., Felten, A., Fiorilli, S., Debecker, D. P., Aprile, C., Journal of Catalysis, 2021, 400, 83-92.
4. Godard, N., Collard, X., Vivian, A., Bivona, L. A., Fiorilli, S., Fusaro, L., Aprile, C., Applied Catalysis A: General, 2018, 556, 73-80.

Acknowledgements: This communication is supported by the F.R.S-FNRS via the funding of the FRIA grant of A. Maertens and under grants n°GEQ U.G014.19 and EQP U.N034.17. This research used resources of the PC2 and the MORPH-IM platforms located at the University of Namur.