Direct injection enthalpimetry in the routine determination of the hydroxyl value of alkylphenols

Abstract

A thermometric method in which the heat of reaction is used as a quantitative measure of the hydroxyl value of alkylphenols is in routine use. This method has replaced a lengthy acetylation procedure that necessitated measuring the difference between two titrations.

By catalysing the acetylation reaction with perchloric acid and then measuring the temperature rise resulting from the heat of reaction, a method has been developed that takes less than 5 minutes to carry out. Standardisation of reagents is unnecessary and only one volumetric measurement is important to the result. The advantages of this method are simplicity and speed, and also a repeatability equal to that of time consuming conventional titration techniques.