ISO 6796:1981
Polyglycols for industrial use — Determination of hydroxyl number — Phthalic anhydride esterification method
T/GDCA 015-2022
UNE 55717:1984
SURFACE ACTIVE AGENTS. POLYGLYCOLS. DETERMINATION OF HYDROXYL NUMBER. PHTHALIC ANHYDRIDE ESTERIFICATION METHOD
ASTM E326-96
Test Method for Hydroxyl Groups by Phthalic Anhydride Esterification (Withdrawn 2001)
ASTM E335-96
Standard Test Method for Hydroxyl Groups by Pyromellitic Dianhydride Esterification (Withdrawn 2003)