Dediazoniation of Arenediazonium Ions. Part XIX. Effect of Thiocyanate Ion in the Reactions of 2,4,6-Trimethylbenzenediazonium Tetrafluoroborate in 2,2,2-trifluoroethanol

Article abstract of DOI:10.1002/hlca.19810640831

The dediazoniation of 2,4,6-trimethylbenzenediazonium tetrafluoroborate (1) in 2,2,2-trifluoroethanol (TFE) was studied in the presence of potassium thiocyanate.The effect of added salt on the dediazoniation rate, the N_α-N_β rearrangement (Eqn. 2), the exchange of the 15N-labelled diazo group with molecular nitrogen (Eqn. 3), and the reaction products was determinated.With 0.3M KSCN a dediazoniation-rate increase of 16.5percent was achieved, and the amounts of rearranged and exchanged product were reduced to 88percent and 70percent, respectively, of the values found in pure TFE.The dediazoniation products formed are ArF (3), ArOCH2CF3 (4), ArSCN (5), ArNCS (6) and traces of 5,7-dimethylindazole (7).All the data are in agreement with, and support the previously proposed mechanism (Eqn. 1) of heterolytic dediazoniation of arenediazonium salts.