Decomposition of Methyl Oleate Hydroperoxides in vacuo on Exposure to Visible Light and Heat
✍ Scribed by Sastry, Y. S. R. ;Lakshminarayana, G.
- Publisher
- John Wiley and Sons
- Year
- 1971
- Weight
- 342 KB
- Volume
- 73
- Category
- Article
- ISSN
- 0931-5985
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✦ Synopsis
Methyl oleate hydroperoxides were decomposed in sealed tubes under vacuum either by exposing to light from a 500 Wtungsten bulb or by heating in the dark at 6 9 C. Heat treatment caused a faster reduction in peroxide value than thc exposure to light. Free acids, hydrocarbons and epoxy compounds were among the products of decomposition. The formation of similar decomposition products in both the treatments suggests that the mechanism of decomposition is the same.
Zersetzung der Methyloleat-Hydroperoxyde im Vakuum durch sichtbares Licht und Wärme
Methyloleat-Hydroperoxyde wurden in zugeschmolzenen Röhrchen unter Vakuum entweder durch Licht einer 500 W Wolfrarn-Birne oder durch Erhitzen im Dunkeln auf 63O C zersetzt. Die thermische Behandlung verursachte eine raschere Abnahme der Peroxydzahl als die Belichtung. Unter den Zersetzungsprodukten befanden sich freie Säuren, Kohlenwasserstoffe und Epoxy-Verbindungen. Die Bildung ähnlicher Zersetzungcprodukte bei beiden Behandlungsarten deutet auf den gleichen Zersetzungsmechanismus hin.
I n t r o d u c t i o n
Autoxidation of fats involves initiation of free radicals by catalysts such as metals, heat and light, formation of peroxides, and decomposition .of these peroxides for further chain-reactions. If the decomposition of peroxides is to be investigated as such, the first phase of autoxidation, namely formation of peroxides has to be curtailed by cutting off accessibility to oxygen. Of the studies on decomposition of hydroperoxides catalysed by various factors such as heat light lo, 11, metals 12, antioxidants 13, mineral and lower organic acids 12, l3 and hematin 14, only the thermal decomposition was systematically investigated in vacuo6. I t was recently reported that peroxide values of oxidised fats fell in the absence of air on exposure to diffused sunlight lo-ll. However no systematic work seems to have been done on photodecomposition in vacuo.