A facile and efficient method to improve the selectivity of methyl lactate in the chemocatalytic conversion of glucose catalyzed by homogeneous Lewis acid

• Carbohydrates were converted to methyl lactate (MLA) catalyzed by SnCln.
• MLA selectivity was improved by controlling the acidity of reaction solution.
• Inorganic base such as NaOH was used to adjust the acidity of reaction solution.
• The method can efficiently convert glucose, fructose, and sucrose to MLA.

A facile and efficient method to improve the selectivity of methyl lactate (MLA) in the chemical conversion of glucose in methanol catalyzed by homogeneous Lewis acid was established. The yield of MLA was efficiently improved through controlling the acidity of the reaction solution by neutralization of protons generated from the hydrolysis/methanolysis of SnCl4. The mechanism of glucose conversion to MLA catalyzed by SnCl4-NaOH was explored. The effects of the concentration of catalyst and substrate and the reaction temperature and time were systematically studied. The catalyst system of SnCl4-NaOH can efficiently convert glucose, fructose, and sucrose to MLA with yields of 47%, 57%, and 51% at 160 °C for 2.5 h, respectively. The catalyst can be regenerated and reused at least three times in the conversion of glucose to MLA without significant loss of activity and selectivity.

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