Cooperative In–Sn catalyst system for efficient methyl lactate synthesis from biomass-derived sugars

• Published in: Applied catalysis. B, Environmental Vol. 183; pp. 8 - 17
• Main Authors: Nemoto, Koji, Hirano, Yoshiaki, Hirata, Kei-ichi, Takahashi, Tsukasa, Tsuneki, Hideaki, Tominaga, Ken-ichi, Sato, Kazuhiko
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2016
• Subjects: Biomass; Catalysis; Catalysts; Chlorides; Conversion; Esters; Indium; Lactate; Lactates; Lewis acid; Sugars; Synergistic effect; Tin; Lewis acid; Tin; Biomass; Synergistic effect; Lactate; Indium
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2015.10.015

[Display omitted] •One-pot transformation of sugars to methyl lactate catalyzed by two-component catalyst.•The synergistic effect of In and Sn species resulted in efficient formation of methyl lactate.•The retro-aldol reaction of fructose to trioses was mainly catalyzed by In species.•The isomerization of trioses to methyl lactate was mainly catalyzed by Sn species.•The catalytic process holds great advantages over the conventional fermentation process. The catalytic conversion of sugars to lactic acid esters holds great advantages over the conventional fermentation process; the reaction is faster and the product can be separated with a simple distillation process. As the conversion of the sugar to the lactic acid ester involves several elemental reactions, multi-component catalyst systems were expected to be effective for this reaction. This paper reports the use of a combination of indium chloride and tin chloride to synergistically catalyze the formation of methyl lactate (MeLac) from sugars in the presence of tetrafluoroborate salts, the maximum yield of which reaches 72%. A plausible reaction scheme is also proposed based on the electrospray ionization mass spectroscopy analyses of the reaction solutions and the effects of the indium species, tin species, and tetrafluoroborate salts on each elemental step from fructose to MeLac.