An encapsulation strategy to design an In-TS-1 zeolite enabling high activity and stability toward the efficient production of methyl lactate from fructose

Abstract

Polylactic acid (PLA), a biomass material, has garnered increasing interest as a biodegradable alternative for the production of eco-friendly plastics. Accordingly, the sustainable synthesis of lactic acid (LA) and its derivatives from biomass sources is emerging as a viable approach. In this work, an In-TS-1 zeolite with exceptional catalytic activity and stability was successfully synthesized using a hydrothermal method and applied for the efficient one-pot conversion of fructose into methyl lactate (MLA). Characterization of the resulting catalysts, including pyridine-adsorbed Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, and energy dispersive X-ray spectroscopy for elemental mapping, confirmed that the uniform dispersion of indium (In) species contributed to its favorable acidity and significantly boosted the reaction efficiency. Under optimized reaction conditions, a remarkable MLA yield of 71.9% was achieved upon the complete conversion of fructose. The selectivity of MLA remained consistent over 14 cycles, underscoring its extraordinary stability under hydrothermal conditions attributed to the confinement of In species within the zeolite framework. This research technique establishes a potential strategy for the large-scale manufacture of LA and its esters, offering a sustainable and efficient path for the development of biodegradable plastics.