A Colorimetric Method for the Determination of Acetic Acid in Wood Hydrolyzate Containing a Large Amount of Sulfuric Acid

Abstract

A method for the determination of acetic acid in presence of a large amount of sulfuric acid has been developed. The method consists of the following procedures. The sample is neutralyzed by barium carbonate. Barium sulfate and excess of barium carbonate are filtered off. On addition of sulfuric acid, acetic acid is extracted with n-butanol from the filtrate. By the reaction of acetic and sulfuric acids in butanol layer with aniline and furfural, a red color is produced. The color produced by sulfuric acid is bleached by treating with barium carbonate powder and the absorbancy of the color produced by acetic acid is measured in a photometer. Acetic acid determination by this method is disturbed by some other acids which give soluble barium salts but the acids which give insoluble barium salts do not disturb.