Adapted from (Froment and Bischoff 1990). The oxidation reaction of o-xylene to produce phthalic anhydride is highly exothermic and is carried out in a PFR reactor using a melt salt as a refrigerant (NaNO3). The o-xylene is mixed with air before entering the reactor trying to have very small amounts of oil into the mixture. Under these conditions there is a large excess of oxygen which causes the reaction to be pseudo-first order with respect to the concentration of o-xylene.
where A, B, C, and D represent o-xylene, oxygen, phthalic anhydride, and water, respectively. A mixture of 690