Process Safety and Environmental Protection, Vol.90, No.5, 404-410, 2012
Inherently safer reactors: Improved efficiency of 3-picoline N-oxidation in the temperature range 110-125 degrees C
Alkylpyridine N-oxides are important intermediates in the pharmaceutical and agrochemicals industries. The N-oxides are produced via the homogeneously catalyzed oxidation of the respective alkylpyridines using a 50% excess of hydrogen peroxide. The competitive hydrogen peroxide decomposition produces oxygen in the flammable environment of alkylpyridines and thus forms a key hazard for this reaction. In this work, the N-oxidation was performed under pressure in the temperature range of 110-125 degrees C with different catalyst concentrations. It was shown that temperature had an undisputable positive effect on the N-oxidation efficiency. The accurate measurement of the pressure rise due to decomposition was difficult. However, only 5% of the added H2O2 decomposed when stoichiometric quantities were employed, even in the temperature of 110 degrees C. The N-oxidation was very efficient, even when the lowest concentration of catalyst employed in this study was used. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Keywords:3-Methylpyridine;3-Picoline N-oxide;Hydrogen peroxide;Thermal decomposition;Reaction calorimetry