Synthesis of 2-methylpentanol from ethylene in single pot using eco-friendly HRhCO(PPh3)3 supported on activated hydrotalcite as a multi-functional catalyst

The [Rh-complex/HT-Act] catalyst was synthesized by the impregnation of HRhCO(PPh3)3 [Rh-complex] on the surface of activated hydrotalcite [HT-Act] and characterized by 31P NMR, FT-IR, P-XRD and TGA. The multi-functional potential of [Rh-complex/HT-Act] catalyst was evaluated for the selective synthesis of 2-methylpentanol from ethylene employing hydroformylation, aldol condensation and hydrogenation reactions in single pot. The catalytic activity of [Rh-complex/HT-Act] was studied in detail as a function of Mg/Al molar ratio of [HT-Act], reaction temperature, partial pressure of ethylene, CO:H2 ratio and nature of solvent used. The selectivity of 2-methylpentanol was observed to increase from 56 to 79% on increasing the Mg/Al molar ratio of [HT-Act] from 1.5 to 3.5. Polar solvent such as methanol showed 86% selectivity for 2-methylpentanol as compared to non-polar solvents. Kinetic profiles of the various products formed during the course of reaction were in agreement with the reaction pathway proposed to understand the role of each component of [Rh-complex/HT-Act] catalyst for the formation of 2-methylpentanol.

Graphical abstractThe multi-functional [Rh-complex/HT-Act] catalyst system was synthesized by impregnation of HRhCO(PPh3)3 [Rh-complex] on the surface of activated hydrotalcite [HT-Act] for selective synthesis of 2-methylpentanol from ethylene in single pot. The maximum selectivity of 2-ethylpentanol (86%) was observed in polar solvents such as methanol as compared to non-polar solvents toluene (79%).Figure optionsDownload full-size imageDownload as PowerPoint slide