Experimental and kinetic study of the nitration of 2-ethylhexanol in capillary microreactors

The nitration process of 2-ethylhexanol (2-EH) with mixed acid was studied in different capillary microreactors. The conversion of 2-EH and selectivity to 2-ethylhexyl nitrate (EHN) were investigated by varying reaction temperature, molar ratio of nitrate to 2-EH, residence time and water content in mixed acid. Under optimized conditions, the conversion of 2-EH and selectivity to EHN could be up to 99% in less than 10 seconds, indicating great potential of microreactors in process intensification. Moreover, with an assumption of homogeneous reaction, a kinetic model based on first order kinetics for nitric acid and 2-EH was proposed to determine both the apparent and intrinsic reaction kinetics. By taking into account the activity of solutes that depend on the acidity (Mc), the intrinsic kinetic was obtained, which is independent of the sulfuric acid concentration. The reaction model can well predict the conversion of 2-EH.