Nitric acid decomposition kinetics in mixed acid and their use in the modeling of aromatic nitration

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2013-07, Vol.228, p.366-373
• Main Authors: Di Somma, Ilaria, Marotta, Raffaele, Andreozzi, Roberto, Caprio, Vincenzo
• Format: Article
• Language: English
• Subjects: chemical composition; Chemical engineering; Decomposition; Evaporation; Kinetics; Mathematical models; Methyl m-nitrobenzoate; Mixed acid; Nitration; Nitric acid; Nitric acid decomposition; Open systems; Reaction kinetics; temperature
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2013.04.100

•A kinetic characterization of nitric acid decomposition in mixed acid is achieved.•The decomposition arises in an open system from which formed gases may escape.•The nitration of 3-nitrobenzoate in an open system has been modeled.•A thermal balance equation has been included in the developed model.•The target nitration carried out under isoperibolic batch mode has been simulated. Nitric acid decomposition in mixed acid (an aqueous mixture of nitric and sulfuric acids) was studied from a chemical and a kinetic point of view. The study was focused on the behavior of the reactive mixture in an open system in which the gas formed through the decomposition process can leave the vessel. The reaction network, through which the system could develop, depending on the chemical composition of the mixture and on the temperature, was completely characterized. The data collected indicate that water evaporation can significantly influence the system behavior. Isothermal experiments were carried out to estimate the unknown kinetic parameters through the adoption of a mathematical model able to predict the system behavior at varying process conditions. The proposed model and the estimated parameters were validated through the use of the results collected in a set of experimental runs performed during the nitration of methyl m-nitrobenzoate (3NMB) in mixed acid media.