Oxygen Absorption Studies of Unsaturated Fatty Acids of Linseed and Melon Seed Oils; Effects of Temperature and Blending

Manometric oxygen induced polymerization of the fatty acids of Linseed (L.S.A) and Melon Seed (M.S.A) oils and blends of the fatty acids were monitored at 10 min intervals for 5 h at 31.5, 45, 60, 75 and 90°C. Moles of absorbed oxygen were calculated from pressures of un-reacted oxygen using the ideal gas equation. The moles of absorbed oxygen were plotted against time for the acids and their blends at the various temperatures. The plots in general show parabolic rise in oxygen absorption with time for each acid and blend for all temperatures except for 90°C when the optimum oxygen absorption was reached at about the 4th h. Oxygen absorptions were highest within the first 2.5 h for all temperatures except for 90°C where the rates were highest within the first 1.5 h. The 5th h oxygen absorption values were plotted against temperature for various blends. The plots show that the optimum oxygen absorption temperature range for the neat acids and the various blends was in the range of 60-75°C. Results also show marked improvement in the oxygen absorption characteristics of M.S.A. with synergistic effects in some cases especially when L.S.A. is 60-80% in the blend.