Solventless Olefin Epoxidation Using a Mo–Loaded Sisal Derived Acid-Char Catalyst

Abstract

This study presents a stable, selective and reusable catalyst prepared by a biomass-derived acid-biochar (acid-char) functionalized with the organometallic complex [MoI2(CO)3(MeCN)2] (Mo), yielding a material where the [MoI2(CO)3] core is coordinated at surface functional groups of the acid-char material. The characterization of this catalyst, denoted as Mo@acid-char, by using various complementary techniques confirmed the successful immobilization of the [MoI2(CO)3] core at the surface of the acid-char material. The catalytic activity of the material was evaluated for olefin epoxidation reactions of cis-cyclooctene and R-(+)-limonene, varying relevant reaction parameters such as temperature, solvent and oxidant ratio. The Mo@acid-char showed an excellent selectivity for epoxide products at mild temperature (ca. 328 K). Interestingly, the catalyst exhibited its highest activity when the reaction was carried out under solventless conditions, allowing the catalysts reuse for several cycles. Thus, the synthesized Mo@acid-char contributed for a sustainable use of biomass waste (e. g., sisal) through the development of environmentally friendly processes avoiding the use of solvents.