Thermal Reaction of Safflower Oil in the Presence of Magnesium Iodide

Abstract

Safflower oil was heated in the presence of 5, 2.5, and 1wt% of magnesium iodide at 220, 200, 180, 160, and 140°C. The fatty acid compositions of reaction products were determined by means of GLC and UV methods. Isomerization proceeded extensively at high tempreature and with high catalyst concentration. The amount of conjugated diene formed reached the miximum and then decreased. On the same time, a large amount of substance which has the same retention time as methyl oleate formed. The maximum amount of the substance was 52.3% at 160°C for 4hr with 5% magnesium iodide. As the results of GLC, GC-MS, and oxidative ozonolysis, the substance is a mixture of positional isomers of octadecenoic acid of which double bonds are mainly trans form.The components formed by side reactions such as decomposition, polymerization, and so on, were analyzed by means of GC-MS method. The results show the presence of 9- (o-propyl phenyl) nonanoic acid, 8-phenyl octanoic acid, alkyl iodides, alkyl bezenes, and n-alkanes.The similarity of the substances formed in the thermal reaction with magnesium iodides to those with iodine reported in our former work suggests that free iodine liberated from magnesium iodide in the thermal reaction will play mainly role of catalyst.