Alkaline modifiers as performance boosters in citral hydrogenation over supported ionic liquid catalysts (SILCAs)

Supported ionic liquid catalyst (SILCA) was modified with different alkaline modifiers which were dissolved in ionic liquid. Highly selective reaction route toward citronellal was accomplished. [Display omitted] ► Supported ionic liquid catalysts are modified with alkaline modifiers. ► Catalysts are applied in citral hydrogenation. ► The selectivity of citronellal is enhanced. ► Highly selective reaction route was accomplished. Supported ionic liquid catalysts (SILCAs) consist of nano-scale catalytic species immobilized in an ionic liquid layer which, in turn, is immobilized on a solid support. In this work, novel SILCAs containing various inorganic alkaline modifiers (e.g. potassium hydroxide) were prepared and applied in citral hydrogenation reactions. The supported ionic liquid catalyst systems demonstrated enhanced reaction rates and improved selectivities toward citronellal in citral hydrogenation. With the addition of an alkaline modifier into ionic liquid layer, the catalyst selectivity increased from 16% to 74%. In fact, a highly selective reaction route toward citronellal was accomplished.