Sn(II)-catalyzed β-citronellol esterification: a Brønsted acid-free process for synthesis of fragrances at room temperature

摘要: Simple SnCl2·2H2O was demonstrated to be able catalyze β-citronellol esterification with acetic acid at room temperature under solvent-free conditions, achieving high conversion and ester selectivity (ca. 88% 99%, respectively). Tin(II) chloride is a stable water-tolerant Lewis that commercially available less corrosive than Bronsted catalysts. This selective process an attractive alternative the mineral acid-catalyzed because it avoids product neutralization common in those reactions. The effects of main reaction parameters such as reactant stoichiometry, temperature, solvent, catalyst concentration were assessed. Among tin catalysts evaluated, SnCl2 most active selective. Moreover, sulfuric p-toluenesulfonic catalysts, acids investigated herein, additional advantages being solid catalyst.