International Standard
ISO 4326:1980
Non-ionic surface active agents — Polyethoxylated derivatives — Determination of hydroxyl value — Acetic anhydride method
Reference number
ISO 4326:1980
Edition 1
International Standard
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ISO 4326:1980
Published (Edition 1, 1980)
This standard was last reviewed and confirmed in 2019. Therefore this version remains current.

ISO 4326:1980

ISO 4326:1980
CHF 42
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The hydroxyl group is esterified by acetic anhydride in pyridine solution. The excess of acetic anhydride is hydrolized with water. The acidity which appears during the esterification and the acetic acid formed during the hydrolysis are neutralized by sodium hydroxide solution in the presence of phenolphthalein as indicator. The hydroxyl value is calculated from the difference between the volume od sodium hydroxide solution used for the titration of the blank and of the test solution.

General information

  •  : Published
     : 1980-03
    : International Standard under systematic review [90.20]
  •  : 1
     : 3
  • ISO/TC 91
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