固体超强酸负载镧催化合成乳酸乙酯

Catalytic synthesis of ethyl lactate by lanthanum solid superacid SO_4^(2-)/TiO_2/La_2O_3

以乳酸和乙醇为原料,在SO42-/La2O3-TiO2的催化下,以氧化钙为脱水剂,采用索氏提取器进行回流脱水合成乳酸乙酯。对影响乳酸乙酯酯化率的诸因素进行了考察。结果表明,加入脱水剂和带水剂可以显著提高乳酸乙酯的产率。适宜反应条件为:SO42-/La2O3-TiO2中La3+浓度为0.07 mol/L,陈化14 h,在450℃下焙烧3 h;醇∶酸(摩尔比)=2∶1,催化剂用量为乳酸质量的2.0%,带水剂苯25 mL/0.1 mol乳酸,反应3 h时,酯化率达84.2%。且该催化剂有良好的重复和再生性。

Ethyl lactate was synthesized starting from lactic acid and ethanol over solid super-acid SO4^2-/La2O3-TiO2 catalyst. The reaction was carried out in a Soxhlet extracting set with CaO as dehydrating agent. The influence factors were investigated. The results showed that the productivity of ethyl lactate was obviously improved by adding dehydrating agent and water-carrying agent in the reaction system. The appropriate conditions were as follows： SO4^2-/La2O3-TiO2 was made by 0.07 mol/L La^3＋ , aging time was 14 h,calcinations at 450℃ for 3 h,the mole ratio of alcohol to acid was 2：1 ,reaction time was 3 h,cata- lyst amount was 2% of lactic acid mass,water-carrying agent （benzene） was 25 mL/0.1 mol lactic acid, reaction time was 3 h and esterification yield of ethyl lactate was about 84.2%. And the catalyst was re- used and regenerated.