WP-089
Water content determination in ketones using Hydranal™ NEXTGEN FA reagents
Резюме
Ketones react with the alcohol component in Karl Fischer (KF) reagents. The ketal formation releases water, thereby increasing the water content and falsifying the titration results. This side reaction depends on the reactivity of the respective ketone, and its influence is even more pronounced in coulometric KF titration.
Previous generation coulometric KF reagents only suppress this side reaction to an extent. Even though they do not contain methanol, they always contain an alcohol component. The presence of alcohol in KF reagents results in a stoichiometric reaction of 1:1 between water and iodine. Without alcohol, the stoichiometry is changed, resulting in a 2:1 reaction of water with iodine (i.e., the Bunsen reaction).
The Hydranal™ NEXTGEN FA reagents from Honeywell do not contain any alcohol; here, FA is an abbreviation for «free of alcohol». The Bunsen reaction is suppressed with methanesulfonic acid which is present as a stabilizer in these reagents, therefore resulting in a 1:1 reaction of water and iodine. With Hydranal™ NEXTGEN FA reagents, the water content in ketones can be determined quickly and reliably. Compared to other existing KF reagents for ketones on the market, the side reactions are measurably better suppressed when using Honeywell Hydranal™ NEXTGEN FA reagents.