材料期刊网

采用酸性氧化铝做催化剂对蓖麻油(CO)进行环氧化,探索环氧化反应时间、反应温度和催化剂等不同条件对蓖麻油环氧化的影响,从而优化出合适的反应条件,采用傅立叶变换红外光谱法(FTIR)、热重分析法(TG)对制备的环氧化蓖麻油(ECO)的结构和性质等进行了研究. 利用盐酸-丙酮法对环氧化产物进行环氧值的测定,结果表明,在优化条件下,即采用酸性氧化铝做催化剂,H_2O_2的滴加温度保持在50～55 ℃,反应温度65 ℃,反应时间控制在11.5 h,同时加入尿素做稳定剂,可以提高H2O2的利用率,使环氧化蓖麻油的环氧值达到2.094×10~(-3) mol/g. 对ECO的性能表征结果表明,ECO粘度随着环氧值的增大而增大,随着温度的升高而降低. ECO在250 ℃前能够基本保持稳定,而后开始分解,有3个明显的热分解阶段:250～390 ℃、390～470 ℃、470～580 ℃,ECO的热稳定性较好.

Influences of the reaction conditions including the reaction temperature, reaction time and the quantity of the catalyst added on the epoxidation of castor oil were investigated using acidic alumina as the catalyst, in order to optimize the reaction conditions. The structure and properties of epoxidized castor oil were characterized by FT-IR and TG. The epoxy value of product ECO was measured by hydrochloric acid-acetone method. The utilization of H_2O_2 could be improved and the epoxy value of castor oil could be as high as 2.094×10~(-3) mol/g under optimized synthetic conditions, where acidic alumina was used as catalyst, thiourea was added as stabilizer, the temperature of added H_2O_2 solution was 50～55 ℃, the reaction temperature were kept at 65 ℃ for 11.5 h. The viscosity of ECO increases with the increas of epoxy value and lower with temperature increase. ECO remains stable up to 250 ℃ then started to decompose. There were three obvious thermal decomposition stages:250～390 ℃, 390～470 ℃, 470～580 ℃, which showed ECO had a good thermal stability.