Kinetic modeling validation and extension for heterogeneous benzaldehyde nitration

2- and 3- nitrobenzaldehyde are two industrial intermediates involved in the production a wide range of bulk and fine chemicals ranging from dyes, plastic additives, fragrances, and flavourings, to highly priced materials such as pharmaceuticals and innovative materials[1]. In recent investigations, an interest was shown for benzaldehyde nitration kinetic modeling in mixtures of nitric and sulfuric acid, namely mixed acid[2] . Moreover, the possibility of realizing tandem oxidation/nitration of benzyl alcohol to synthesize nitrobenzaldehydes was recently demonstrated[3]. The above investigations and modeling were carried out using an organic substrate concentration lower than its solubility in the acidic aqueous phase to realize homogeneous conditions and prevent the kinetic parameters estimation from being affected by interphase mass transfer. However, preliminary studies suggested the importance of a heterogeneous-phase reaction characterization to explain discrepancies obtained in commercially available microreactors[3]. To this regard, in this work an experimental campaign was carried out under heterogeneous conditions in batch reactors in order to extend and validate the available kinetic model. The results were compared with those obtained under homogeneous conditions and in a microreactor. Microreactors could be an attractive alternative to safely carry out hazardous reactions such as highly exothermal tandem oxidations and nitrations.