Fe2(SO4)3·xH2O CATALYTIC ESTERIFICATION OF MANDELIC ACID WITH ALCOHOLS

Mandelates have played an important role in organic synthesis and are used in artificial flavorings and perfumes. Mandelates may be prepared as follows:1). Direct esterification of mandelic acid with alcohols in the presence of sulfuric acid^1,2 or 2,2-dimethoxypropane and sulfuric acid;³ 2). Treatment mandelic acid and iodide in the presence of sodium hydrogen carbonate;⁴ 3). Treatment mandelic acid and alcohols with thionyl chloride.⁵ But these methods have some advantages and are not universally applicable. For example, the direct esterification catalyzed by sulfuric acid is not suitable for acid sensitive compounds and has the disadvantages of the corrosivity of strong acid and usually accompanying side reactions such as carbonization,oxidation, etherification, etc. We now reported the catalytic esterification of mandelic acid with a serious of alcohols using Fe₂(SO₄)₃·xH₂O as a new convenient catalyst.