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The method suggested in ASTM E 1899-08 is based on the reaction of the primary and secondary hydroxyl groups with excess toluene-4-sulfonyl-isocyanate (TSI) to form an acidic carbamate. The latter can then be titrated in a non-aqueous medium with the strong base tetrabutyl-ammonium hydroxide (TBAOH).
The method suggested in DIN 53240-2 is based on the catalyzed acetylation of the hydroxyl group. After hydrolysis of the intermediate, the remaining acetic acid is titrated in a non-aqueous medium with alcoholic KOH solution.
The two methods allow, for example, the determination of polyols and oxooils without any tedious and time consuming sample preparation and is therefore a big benefit for laboratories that have to analyze a great number of these samples per day.
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