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The urethane reaction kinetics of 1,2-propanediol with phenyl isocyanate are investigated in different solvents, such as xylene, toluene and dimethylformamide. In-situ FT-IR is used to monitor the reaction to work out rate constant. It showsthat the urethane reaction has been found to be a second order reaction, solvents largely affects reaction rates. The reaction is largely accelerated in polar solvents, following the order of dimethylformamide > toluene > xylene. Further more, when dimethylformamide is used as solvent, the rate constants are different between initial stage and final stage, which belongs to different hydroxyls in 1,2-propanediol. However, when toluene or xylene is used as solvent, the rate constant is the same. That is, there is no reactivity difference for hydroxyls in 1,2-propanediol.