Determination of phenylurethane and isocyanate groups in isocyanates

Reactions of phenylurethane and isocyanate groups of arylisocyanates with secondary amines are studied by IR spectrometry and potentiometric titration. It is found that the rate of the reaction between isocyanate groups and diethylamine is nearly independent of the solvent nature. When protophilic solvents are used, solvent molecules and isocyanate groups form associates, which interfere with the determination. Optimal conditions are determined for the determination of phenylurethane and isocyanate groups. Procedures are developed for determining mass fractions of isocyanate and phenylurethane groups when they are present simultaneously. © 1999 MAEe Cyrillic signK "Hayκa/Interperiodica".