The trichlorophenol (TCP) synthesis was kinetically modeled on the basis of anal., kinetic, and thermodn. data and the operation of the semibatch process and selected runaway processes were simulated. The model included mass and heat balances. Features of complex reactions were reaction rate consts. and isoperobolic temp. course. The temp. sensitivity of the reaction rate consts. of the partial reactions must be regarded in complex reactions. Hazards can occur by exothermic secondary reactions and by toxic and environmental-hazardous byproducts.