Comment on "Kinetics of a Diels-Alder Reaction of Maleic Anhydride and Isoprene in Supercritical CO₂"

A comment corrects an analysis of data in the thesis of G.C. Alexander, reported by Glebov et al. recalculated rate constants measured by Alexander and Paulaitis for the Diels-Alder reaction of maleic anhydride (MA) with isoprene in supercritical CO₂. They used the results of a GC calibration done to determine the GC response to MA relative to the reaction product, methylcyclohexene dicarboxylic anhydride (MCDA). Two column headings in the table of results for the grams of MA and the grams of MCDA in the standard solutions were inadvertently transposed, except for the last two entries, which were under the correct column headings. Glebov et at. used this expression with the reported parameters in their analysis, but assumed the calibration was done for the reaction product, MCDA. The result contradicts the observation of a higher apparent reaction rate in the two-phase region at 60°C and 100 atm if the interpretation by Glebov et al. is correct; i.e., the measurements carried out at 60°C by Alexander and Paulaitis were under conditions of two-phase equilibrium. A response to this comment was included.