1968 年 17 巻 12 号 p. 685-688
An oxirane group was treated with 100200% excess of HCl, and remaining HCl was determined by applying a reaction in which I2, is liberated by the action of HCl to a mixture of KBrO3 and KI. Thus, 10 ml of 1/10 N-HCl, dioxane-CCl4 (1 : 1) solution, was added into a solution in which 0.10.2 g of epoxystearic acid was dissolved in 10 ml of CCl4, and swirled occasionally for 10 min. Then 10 ml of an aqueous solution containing 0.5 g of KBrO3 and 0.5 g of KI was poured into the solution, and the mixture was shaken for 1 min followed by allowing to stand for 4 min. Iodine liberated was determined with 1/10 N-Na2S2O3 solution after adding 30 ml of water. Similar procedure was accomplished without epoxy compound. No compensation for neutralization value was necessary.
The value of oxirane oxygen content obtained accorded with that by the A.O.C.S. method. Anisaldehyde, benzoyl peroxide, cetyl and oleyl alcohols, and caprylic, stearic and oleic acids had no effect on the determination. Acetic acid, however, gave lower value of oxirane oxygen content.
The present method was also suitable for the determination of low oxirane oxygen (<1%).