Low-temperature reduction of bio-based cinnamaldehyde to α,β-(un)saturated alcohols enabled by a waste-derived catalyst

A waste eggshell-derived catalyst (CaO-900) was facilely prepared and exhibited high efficiency in selective hydrogenation of bio-based cinnamaldehyde (CAL) to cinnamyl alcohol (COL) with 97% yield at 30 °C. By simply adjusting reaction temperature and time, CAL could be completely converted to 3-phenylpropanol. The predominant catalytic performance of CaO-900 could be attributed to its high alkalinity and large specific surface area. In situ Raman and theoretical calculations indicated that the priority of hydrosilylation toward CAL played a crucial role in the control of product distribution. In addition, the CaO-900 catalyst showed good recyclability.