Synthesis of n-butyl lactate catalyzed by solid superacid SO_4~(2-)/ZrO_2-palygorskite

The n-butyl lactate was synthesized using lactic acid and n-butyl alcohol with solid superacid SO42-/ZrO2-palygorskite as catalyst.Effects of different factors on degree of esterification were investigated.The results showed that the optimal reaction conditions were as follows:the molar ratio of n-butyl alcohol to lactic acid was 3.0:1,the amount of catalyst was 4.0%,reacting at 115℃for 3.0 h,and it resulted in esterification up to 96.64%. The results also revealed the solid superacid SO42-/ZrO2-palygorskite catalyst could be reused by simple phase-separation,and the esterification was still up to 92.04%even after 5 times recycling.