An effective way to produce fatty alcohol through coupling fatty acid with CO2 hydrogenation over CuZnZrOx/C-N catalyst

Abstract

The hydrogenation of fatty acids to fatty alcohols, alongside the hydrogenation of CO₂ to methanol, represents crucial pathways for addressing the depletion of fossil resources and achieving carbon neutrality. However, the catalytic conversion rates of these two reactions remain low under mild conditions. In this study, we discovered an innovative approach that couples stearic acid (C₁₇COOH) hydrogenation with CO₂ hydrogenation in a one-pot catalytic tandem process using the optimized CuZn2ZrO_x/C-N catalyst. This method significantly enhances the yields of methanol and fatty alcohol under mild reaction conditions of 200 °C, 3 MPa, 6 h, with a H₂:CO₂ ratio of 3:1. The reaction mechanism revealed that stearic acid methyl ester (C₁₇COOCH₃) acts as a key intermediate in the coupling process. Specifically, the in situ methanol produced from CO₂ hydrogenation is converted by C₁₇COOH into C₁₇COOCH₃, which is then hydrogenated to form stearic alcohol. This coupling reaction offers important insights for the simultaneous utilization of CO₂ and biomass-derived fatty acids in producing value-added chemicals. Furthermore, our findings could inspire the design of more synergistically coupled catalytic reactions that leverage dual-promotional effects for the hydrogenation of CO₂ and carboxylic acid compounds. This approach not only enhances the efficiency of these transformations but also aligns with the broader goals of sustainability and resource efficiency in chemical processes.