Quantitative production of butenes from biomass-derived γ-valerolactone catalysed by hetero-atomic MFI zeolite

Efficient production of light olefins from renewable biomass is a vital and challenging target to achieve future sustainable chemical processes. Here we report a hetero-atomic MFI-type zeolite (NbAlS-1), over which aqueous solutions of γ-valerolactone (GVL), obtained from biomass-derived carbohydrates, can be quantitatively converted to butenes with a yield of >99% at ambient pressure under continuous flow conditions. NbAlS-1 incorporates simultaneously niobium(V) and aluminium(III) centres into the framework and thus has a desirable distribution of Lewis and Brønsted acid sites with optimal strength. Synchrotron X-ray diffraction and absorption spectroscopy show that there is cooperativity between Nb(V) and Brønsted acid sites on confined adsorption of GVL, while the catalytic mechanism for conversion of confined GVL to butenes is revealed by in situ inelastic neutron scattering, coupled with modelling. This study offers a prospect for the sustainable production of butene as a platform chemical for the manufacture of renewable materials.