Tolylene-2,4-diisocyanate (2,4-TDI) 1reacts with methanol through two simultaneous paths in the polyurethane reaction, which involve two different intermediates – tolylene-4-carbamatic-2-isocyanate 2and tolylene-2-carbamatic-4-isocyanate 3, and the final product is tolylene-2,4-dicarbamate 4. The –CH3chemical shifts in benzene ring in compounds 1, 2, 3and 4can be easily tested and well distinguished, through which those four compounds are quantified and their kinetics are investigated. It shows that four rate constants for the tolylene-2,4-diisocyanate–methanol reaction in CCl4at 50°C are k1=9.6×10−2h−2mol−2min−1, k2=1.4×10−2h−2mol−2min−1, k3=4.0×10−3h−2mol−2min−1, k4=1.4×10−3h−2mol−2min−1. (k1is the reaction rate constant from compounds 1to 2; k2is the reaction rate constant from compounds 1to 3; k3is the reaction rate constant from compounds 3to 4; k4is the reaction rate constant from compounds 2to 4).