Unsteady state process operation has been studied for three common cases: (i) varying inputs (compositions and flow rate); (ii) processes themselves generating oscillations and (iii) combination of (i) and (ii) to see the combined effect. It is observed that sometimes operation at unsteady state, i.e. dynamic operation, gives higher productivity than the operation at steady state. The various parametric studies have been performed to study the effect of input fluctuations. Unsymmetrical fluctuations in process output have been observed with symmetric sinusoidal disturbances in process inputs. Chemical oscillatory behavior is found very sensitive to disturbance. The reactant concentration and temperature of the process output are found strongly dependent on each other. The variation in input composition is found to be prominent effect on the process output. The variation in temperature and overall heat transfer coefficient has significant effect in chemical oscillatory system, studied herein. (C) 2004 Elsevier B.V. All rights reserved.