<![CDATA[Isopentanol (3-methyl-1-butanol) is a versatile higher alcohol with potential applications as a renewable fuel component and chemical intermediate. This study presents a sustainable route for producing isopentanol from fallen Gmelina arborea leaf biomass through barium chloride (BaCl2)-catalysed thermal hydrolysis under mild temperatures (60–90 °C) and atmospheric pressure. The approach integrates waste-biomass valorisation, renewable feedstock utilisation, and low-cost catalysis, thereby supporting the principles of a circular bioeconomy and contributing to Sustainable Development Goal (SDG) 12 (Responsible Consumption and Production) through the conversion of otherwise discarded leaf residues into a value-added chemical. It also supports SDG 7 (Affordable and Clean Energy) by exploring a renewable pathway to a higher alcohol with biofuel potential and SDG 9 (Industry, Innovation and Infrastructure) through the development of a simple catalytic conversion process. The effects of reaction temperature and catalyst loading (0.5–1.0%) were investigated, and products were identified and quantified by Gas Chromatography–Mass Spectrometry (GC–MS). Temperature (p = 0.0013) and catalyst loading (p = 0.048) significantly affected isopentanol yield, while their interaction was not significant. The highest measured yield in the experimental dataset was 452.8 mg/g at 80 °C and 0.5% BaCl2 loading. The results indicate that waste Gmelina arborea leaves can serve as a non-food renewable feedstock for higher-alcohol production, with potential environmental and resource-efficiency benefits consistent with SDGs 7, 9, and 12.]]>
