<p> The temperature policy with time is sought which maximizes a performance index for a fixed time in a tubular reactor with uniform temperature, decaying catalyst, and two first-order irreversible parallel reactions. </p> <p> For the case where the performance index is the total amount of desired product produced, an analogy between the optimization problems for a first-order reversible reaction and a parallel reaction first-order in both. paths is developed. </p> <p> A numerical procedure together with theoretical developments is used to solve the problem for a more general performance index which takes into account the cost of the reactant as well as the value of the desired product. The problem is· treated in the format of Pontryagin's Maximum Principle. </p> / Thesis / Master of Engineering (MEngr)