ISO/TR 9372:1993

Plastics — Basic materials for polyurethanes — Determination of the amounts of 2,4- and 2,6-isomers in toluenediisocyanate by infrared spectroscopy

The principle of the method is preparing a cyclohexane solution of the sample to be analyzed, measuring the absorbance for the 810 cm^-1 and 782 cm^-1 bands which are characteristic of the 1,2,4- and 1,2,6-positions on the aromatic ring, and calculating the absorbance ratio. Applies to mixtures containing 5 % to 95 % of the 2,4-isomer.