Abstract:The study synthesized a propanediol lactate with lactic acid and propylene glycol as substrate and catalyst by an immobilized Candida rugosa lipase.as catalyst and compared the moisture absorption and water absorption of lactic acid、propylene glycol and propanediol lactate.The optimum reaction conditions were determined and listed as follows: The reaction was stirred at 50 ℃ with hexane as solvent,0 g/L initial lactic acid concentration and then feed at 0.01mol/L for 20 h,0.4 mol/L propylene glycol concentration,0.2 g/L immobilized lipase,2.0 g/L molecular sieve,and the reaction time is 60 h.With this optimum conditions,the conversion percent of lactic acid to propanediol lactate was achieved at 97.3%.The purified product after reaction was proved as propanediol lactate by MS and infrared spectrum analysis which content was above 99%.Then the moisture absorption and water absorption of lactic acid,propylene glycol and propanediol lactate were compared and the results shown that the effect of moisture absorption of propanediol lactate was better than that of lactic acid and propylene glycol,respectively.The effect of water absorption was the same as that of propylene glycol in the same temperature and humidity condition.Propanediol lactate was used as cigarette additive.The smoke was comfortable and the dry sensation was reduced.
