Analytical Instrumentation
Automatic Determination of the Hydroxyl Number (Hn) According to ASTM E 1899-08 and Din 53240-2
Oct 12 2015
Metrohm (Switzerland) presents a fully automated titrimetric method for the determination of the hydroxyl number according to ASTM E 1899-08 and DIN 53240-2. The hydroxyl number is defined as the mg of KOH equivalent to the hydroxyl content of 1 g of sample. The system used to carry out the test consists of: 814 USB Sample Processor, 905 Titrando, 800 Dosino, Solvotrode and the tiamo software.
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 catalysed 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 analyse a great number of these samples per day.
Digital Edition
PIN 25.1 Feb/March
March 2024
In This Edition Safety - The technology behind the ION Science Tiger XT - Safety with ammonia and LOHCs as hydrogen carriers Analytical Instrumentation - Discussion on new tribology te...
View all digital editions
Events
Apr 24 2024 Mumbai, India
Apr 24 2024 Jakarta, Indonesia
Apr 28 2024 Montreal, Quebec, Canada
Apr 30 2024 Birmingham, UK
May 03 2024 Seoul, South Korea