Oxyrane oxygen of non-terminal epoxy compounds was determined with each method of hydrogen chloride-ether, dioxane and acetic acid solutions, and hydrogen bromide-acetic acid solution.
It was found that water contained in the sample solution lowers the accuracy of determination.
Hydrogen bromide-acetic acid solution method (Durbetaki's method) showed better accuracy among the above methods.
Anhydrous hydrogen bromide-acetic acid solution was prepared easily by means of a procedure that hydrobromic acid was dissolved with acetic acid, and then equivalent amount of acetic anhydride to water was added into the solution.
To increase the accuracy of determination, Durbetaki's method was modified as follows : In case standardization of hydrogen bromide-acetic acid solution, sodium carbonate was dissolved with 10ml of acetic acid, and then 10ml of benzene was added into the solution. The sample was dissolved with mixture of 10ml of benzene and 5ml of acetic acid.
Interference for the determination was also investigated.
