“…However, a literature survey indicated that there is still a need to find new nitrating systems to overcome the difficulties associated with current production processes of 5-nitrosalicylic acid. An alternative system with respect to the classic "mixed acid" could be represented by the mixture nitric acid/acetic acid/acetic anhydride which has been found in the past to give good results with the nitration of phenol and the esterification of carnitine [5,6]. Nevertheless, one has to consider that this system is not free of explosion hazards arising from the formation of intermediate acetylnitrate.…”