Determination of Moisture in iso-Propanol by Karl Fischer Titration

A new Karl Fischer reagent (abbr. as K.F. reagent) was proposed as titrant for determination of moisture in chemicals containing aldehydes and/or ketones. Methanol and pyridine used in the K.F. reagent of conventional Karl Fischer titrimetric determination of moisture were replaced by ethylene glycol monomethylether (EGME) and N-methyl-diethanolamine (MDEA) respectively. The new K.F. reagent consists of 2 parts: ① K.F. solvent A: mix 269 mL of MDEA with 700 mL of EGME, cool in an icebath and pass in SO2 gas until a surplus mass of 64 g to the total mass was attained; ② K.F. solvent B: dissolve 84.7 g of iodine in 500 mL of EGME. Equal volumes of the above mentioned 2 K.F. solvents were mixed and used as titrant in the Karl Fischer titrimetry. The new K.F. reagent proposed was used in the determination of moisture in iso-propanol, the results obtained were in conformity with the results obtained by using K.F. reagent sold on market. The proposed new K.F. reagent was proved to have the advantages of high efficiency, low toxicity and good stability.