Dehydrative decarbonylation of fatty acids into long-chain olefins over CoNx/NC catalysts

Abstract

The development of highly efficient, low-cost supported catalysts is crucial for directly deoxygenating biomass fatty acids to long-chain olefins. However, additive-free olefin production, by dehydrative decarbonylation from fatty acids, is scarcely conducted owing to competing decarboxylation reactions. Herein, a green and cost-effective strategy is presented to improve the Co-catalyzed dehydrative decarbonylation of stearic acid, which produces a mixture of heptadecenes with yields of up to 41.3 % and a paraffin yield of 14.7 %. Experimental data, along with a detailed catalyst characterization, revealed that the surface CoNx species acted as the dominant active sites. Furthermore, the specific catalytic performance can be attributed to the dense defect sites, abundant vacancies, and mesoporous structures of the N-doped Carbon (NC) support. The as-prepared CoNx/NC catalysts were recovered and reused up to three times without significant deactivation. Additionally, we propose a possible reaction mechanism for fatty acid deoxygenation. This research makes a significant contribution toward advancing the performance of noble-metal-free deoxygenation catalysts for the production of unsaturated compounds in biomass conversions.