混合催化剂催化蓖麻油合成蓖麻油多元醇

Preparation of Castor Oil Polyol by Mixed Catalyst

以可再生的蓖麻油为主要原料,首次采用甲醇钠和三乙醇胺为混合催化剂,与甘油在N2环境中发生酯交换反应,生成蓖麻油单甘脂和蓖麻油甘二酯。考察了催化剂用量、甘油用量、反应温度、反应时间对蓖麻油单甘脂转化率、蓖麻油甘二酯转化率和总转化率的影响,并与传统的催化剂甲醇钠、钛酸四丁酯催化酯交换反应进行了比较。采用FT-IR、GPC对产物的结构、相对分子质量和转化率进行了表征。通过单一变量控制法对反应的条件进行优化。结果表明,催化剂用量为蓖麻油质量的0.75%、蓖麻油和甘油的质量比为50∶12.33、反应温度为180℃、反应时间为2.5 h时,蓖麻油多元醇的转化率最高,可达92.54%,与传统催化剂相比较,混合催化剂不仅提高了产物的转化率和羟值,而且使产品的色泽降低。

The castor oil polyols were prepared by using renewable castor oil as the main raw material, using sodium methoxide and triethanolamine as mixed catalyst, through transesterification reaction with cheap glycerol in nitrogen atmosphere. The effects of catalyst dosage, mass ratio, reaction temperature and reaction time on the conversion rate of castor oil monoglycerides, castor oil Kennedy diester and all product were investigated, respectively. The chemical structures, molecular mass and yield of the products were characterized by means of FT-IR, GPC. The optimum process was optimized by single variable experiment. The highest yield（92.54% ） of castor oil potyol was obtained when mixed catalyst dosage was 0. 75% of the castor oil mass, reaction temperature was 180 ℃, the mass ratio of castor oil and glycerol was 50 ： 12. 33 and reaction time was 2.5 hours. Compared with sodium methoxide and tetrabutyl titanate as catalyst, not only the convention rate but also the hydroxyl value of the product was improved using the mixed catalyst, and the color of the product was reduced.