纳米级固体超强酸SO_4^(2-)/TiO_2催化合成棕榈酸乙酯

Synthesis of Ethyl Palmitate Catalyzed by SO_4^(2-)/TiO_2 Nanosolid Superacid

制备了SO42-/TiO2固体超强酸催化剂,应用TEN表征证明为纳米级,并用于催化棕榈酸和无水乙醇的酯化反应,与普通颗粒的SO42-/TiO2、活性炭固载磷钨杂多酸等固体超强酸催化剂比较,纳米级的SO42-/TiO2做酯化反应催化剂具有更高的催化活性。考察了原料醇酸的量比、反应的时间、催化剂的用量及其重复使用次数等工艺条件对合成棕榈酸乙酯的影响,并对合成的产物进行了熔点、红外光谱分析。酯化反应的最佳的工艺条件是:n(乙醇):n(棕榈酸)=9:l、m(催化剂):m(棕榈酸)=0.06:1、反应温度为80~83℃、反应时间为4 h,用3A分子筛和过量的乙醇代替有毒的有机带水剂除去反应生成的水,酯得率可达98.27%。产品经熔点和红外表征为高纯度的棕榈酸乙酯。本合成路线具有工艺简单,无污染,催化剂用量少并可多次重复使用等特点,符合绿色合成工艺。

Prepared nano - sized TiO2/SO4^2- was characterized by means of TEM, was used as catalyst in the estefi - fication reaction of palmic acid and ethanol, The results showed that nano - sized TiO2/S04^2- exhibited higher ac - tivity in the synthesis of ethyl patmitate then the other solid super acid, such as general sized TIO2/SO4^2- ; HPW/C solid super acid, Using nano - TiO2/SO4^2- as catalyst, the optimum reaction conditions for preparing ethyl palmitate were as follows. Excess of ethanol acted as water entrainer（ water was adsorb with 3A molecular sieve）, n （ethanol） ： n （ palmitic acid） = 9：1, m（eatalyst） ： m（palmitic acid） = 0.06：1,reaction temperature was 80- 83℃ ,and reaction time was 4 h. Underhese condition, yield of ethyl paimitate can reach 98.27 %. The production was characterized by MP and IR and was a pure ethyl palmitate.