Villermaux–Dushman Test of Micromixing Characterization Revisited: Kinetic Effects of Acid Choice and Ionic Strength
The well-known Villermaux-Dushman system is nowadays widely used for examining the micromixing efficiency either in batch or continuous intensified reactors. However, a bibliographic review shows that kinetic data are too scattered for a reliable determination of the micromixing times. The Dushman reaction kinetics is then reexamined with the use of sulfuric and perchloric acids. The results confirm the fifth-order rate law. More precisely, the I-, H+, and IO3- dependence orders on the rate law are, respectively, 2, 2, and 1, under any condition. To be more consistent with the reactant concentrations used in the Villermaux-Dushman test, we extend their studied range, namely, 1.6 x 10(-3) M <= [I-](0) <= 1.6 x 10(-2) M, 1.2 x 10(-4) M <= [H+](0) <= 1.57 x 10(-2) M, and 4 x 10(-5) M <= [IO3-] <= 2.1 X 10(-4) M. The ionic strength varies up to 2 M. The experimental results show that the rate constant is still ionic-strength-dependent. The results obtained with sulfuric and perchloric acids are found to be consistent and in relatively good agreement at small ionic strengths (mu < 0.1 M) only. At a higher ionic strength, the use of sulfuric acid requires sustained attention to the constant of the second dissociation equilibrium. The nonideal solution behavior raising at a high ionic strength makes its estimation deeply sensitive.
Pierrette Guichardon, Carlos Baqueiro, Nelson Ibaseta. Villermaux–Dushman Test of Micromixing Characterization Revisited: Kinetic Effects of Acid Choice and Ionic Strength. Industrial and engineering chemistry research, 2021, 60 (50), pp.18268-18282. ⟨10.1021/acs.iecr.1c03208⟩. ⟨hal-03597451⟩
Journal: Industrial and engineering chemistry research
Date de publication: 22-12-2021