Determination of total free acid in formaldehyde by coulometric catalytic thermometric titration

Abstract

Coulometric catalytic thermometric titration of the total free acid (HCOOH) in formaldehyde of various manufacturers was successfully performed. The indicator reaction was the exothermic polymerization of formaldehyde in the presence of ethanol, catalyzed by strong base. In the titrations, a cathodically polarized platinum generator electrode was employed. The content of free acid in various formaldehyde samples ranged between 0.018 and 0.044 %, and was determined with a standard deviation less than 1.5%. Good agreement was obtained with the results of coulometric photometric and volumetric titrations. © 1983 Wiley Heyden Ltd., Chichester and Akadémiai Kiadó, Budapest.