Reference number
ISO 6796:1981
ISO 6796:1981
© ISO 2025
ISO 6796:1981
Polyglycols for industrial use — Determination of hydroxyl number — Phthalic anhydride esterification method
Edition 1
1981-09
1981-09
Retirada
Resumen
The hydroxy groups present in a test portion are esterified with phthalic anhydride. The excess phthalic anhydrids is hydrolyzed and the phthalic acid formed is neutralized with standard volumetric sodium hydroxide solution. If the sample contains free acidity or alkalinity a corresponding correction is made. From the corrected hydroxyl number, the apparat relative molecular mass may be calculated by a formula given.