In this example, nitrobenzene serves as both the solvent and the oxidizing agent. The reaction, which otherwise has a reputation for being violent, is typically conducted in the presence of ferrous sulfate.[5]Arsenic acid may be used instead of nitrobenzene and the former is better since the reaction is less violent.[6]
^Wahren, M. (1964). "Stabilisotop markierte verbindungen—II , Untersuchung der skraupschen chinolin-synthese mit hilfe von 15N". Tetrahedron. 20 (12): 2773. doi:10.1016/S0040-4020(01)98495-9.