Study on the Synthesis of Menthyl Acetate by S_2O_8~(2-)/Fe_2O_3-TiO_2-Nd_2O_3 Solid Superacid

Menthyl acetate has been synthesized from acetic acid and menthol by using solid superacid S2O2-8/Fe2O3-TiO2-Nd2O3 as catalyst.Some factors influencing the yield of esterification were investigated,including catalyst weight,molar ratio of menthol to acetic acid,reaction time and the times of using repeatedly catalyst.The optimum conditions as follows: molar ratio of menthol to acetic acid was 1:1.8,catalyst's weight was 0.6g(3.85wt %of menthol),reaction time was 6h and reaction temperature was about 130℃,under which the yield of esterification was over 97 %.This kind of catalyst that can be recovered and reused has got no corrosiveness to the equipment and is easy to be separated from the product.Moreover,the product's color and lustre is good as well as the flavor of it is pure,therefore the solid superacid S2O2-8/Fe2O3-TiO2-Nd2O3 is an effective catalyst for esterification of acetic acid with menthol.