KINETIC EVALUATION OF THE EPOXIDATION OF LUFFA CYLINDRICA M. SEED OIL UTILIZING LUFFA FIBRE CATALYST

Abstract

The catalytic valorization of biomass offers a sustainable route for bio-epoxide production. Conventional epoxides produced with non-renewable catalysts pose environmental risks, exhibit poor biodegradability, and incur high production costs. However, Luffa cylindrica fibres have not been explored as precursors for heterogeneous epoxidation catalysts, and the epoxidation of luffa seed oil under catalytic kinetic regimes remains under-investigated. In this study, luffa fibre was sulfonated and converted into a heterogeneous nanocatalyst for the epoxidation of oleic-rich luffa seed oil (LSO). Catalyst activation increased the BET surface area from 294.28 to 353.29 m² g⁻¹ and expanded pore size from 2.69 to 3.13 nm, enhancing reactant diffusion and active site accessibility. Scanning Electron Microscopy (SEM) revealed nano-scale spherical agglomerates, while XRD confirmed crystallite formation (~45 nm) and improved lattice ordering. Fourier Transform Infra-Red (FT-IR) analysis verified the presence of acidic functional groups, and TGA demonstrated thermal stability up to ~420°C. Epoxidation achieved a maximum oxirane value of 5.21 mol at 65°C. Kinetic analysis showed pseudo-first-order behavior with rate constants of 0.0392–0.222 h⁻¹ between 328–338 K, while thermodynamic parameters (Ea = 14.44 kJ mol⁻¹; ΔH = 14.44 kJ mol⁻¹; ΔS = −21.75 cal mol⁻¹ K⁻¹) indicate an endothermic and ordered transition state.