Abstract:

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 H₂O₂ 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 H₂O₂ 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.

Key words: castor oil,epoxy value,epoxidation,acidic alumina