DIRECT SYNTHESIS OF TRICONTANE FROM GMELINA ARBOREA LEAVES VIA MILD CALCIUM HYDROXIDE-CATALYSED ETHANOLYSIS

The sustainable production of wax-range hydrocarbons from renewable resources remains a key challenge in biomass valorization, as most reported routes rely on severe thermal conditions and exhibit low selectivity. In this study, a mild and energy-efficient pathway for the synthesis of long-chain saturated hydrocarbons (C₃₀) from Gmelina arborea leaf biomass is reported using calcium hydroxide-catalysed ethanolysis under atmospheric pressure. A Box-Behnken response surface methodology was employed to evaluate and optimize the effects of temperature (40-60 °C), reaction time (40-60 min), and catalyst loading (1.0-2.0 wt%). Product characterization by GC-MS confirmed the formation of five long-chain n-alkanes, tricontane, alongside other industrially relevant phytochemicals. Hydrocarbon yields varied significantly with operating conditions, ranging from 0.83 to 3.65% (41.25-101.56 mg g⁻¹), with the maximum yield achieved at 50 °C, 50 min, and 1.5% Ca(OH)2. Statistical analysis revealed temperature as the most influential parameter, while reaction time and catalyst loading exhibited pronounced quadratic effects, indicating well-defined optima. Compared with previously reported biomass-based routes requiring high temperatures, this process achieves competitive yields under markedly milder conditions. The findings demonstrate the effectiveness of calcium hydroxide as a low-cost, environmentally benign catalyst and highlight Gmelina arborea waste leaves as a promising feedstock for sustainable production of high-value wax-range hydrocarbons, supporting low-energy biorefinery and circular bioeconomy strategies.