Combined 1,4-butanediol lactonization and transfer hydrogenation/hydrogenolysis of furfural-derivatives under continuous flow conditionsElectronic supplementary information (ESI) available: Catalyst screening, (S)TEM images, TPR profile and liquid hold-up calculations. See DOI: 10.1039/c4cy00213j

The oxygen-free lactonization of 1,4-butanediol to γ-butyrolactone coupled with a sequential reductive upgrading of furfural derivatives following a transfer hydrogenation/hydrogenolysis mechanism was studied over AlO x -supported copper catalysts. The Cu-Al hydrotalcite-like catalyst-precursor was first reduced with H 2 , forming dispersed Cu nanoparticles. The catalyst was characterized and tested for the dehydrogenation of various primary and secondary alcohols, optimizing the activation procedure and reaction conditions. Subsequently, the combined transfer hydrogenation/hydrogenolysis to furfural derivatives was investigated. All reactions were performed under continuous flow conditions to increase the space-time yield and the selectivity towards the desired products, as well as to study the catalyst stability. Sequential butanediol lactonization and transfer hydrogenation/hydrogenolysis of furfural-derivatives offers new opportunities for reductive upgrading of biomass.