Isomerization of Glucose-to-Fructose in Water over a Continuous Flow Reactor using Ca−Al Mixed Oxide as Heterogeneous Catalyst

This work reports the continuous isomerization of glucose to fructose in aqueous media under mild conditions using a mixed oxide hydrotalcite-derived catalyst based on Ca and Al. Different operational parameters of the continuous flow fix-bed catalytic reactor system were studied. At the optimal conditions, the Ca−Al-based catalyst achieved a very high conversion and almost quantitative selectivity towards fructose, this being one of the few successful examples of a heterogeneous catalyst capable of carrying out this reaction in a continuous process. Importantly, catalytic activity held steady during four hours on stream, and slight deactivation occurring could be practically overcome by thermal regeneration of the catalyst.Grant PGC2018-097277-B-I00 funded by MCIN/AEI/10.13039/ 501100011033 and “ERDF A way of making Europe“, and the financial support by the Spanish Government (SEV-2016-0683) and Generalitat Valenciana (GVA, PROMETEO/2018/006) are gratefully acknowledged. Authors also thank the ITQ for the technical support, and the Electron Microscopy Service of Universitat Politècnica de València for instrumental facilities. J.M. thanks the Spanish Government (CTQ-2015-67592) for his PhD fellowship.Peer reviewe