Portal de Periódicos da CAPES

Two phase nitration of toluene—III

1974; Elsevier BV; Volume: 29; Issue: 5 Linguagem: Inglês

10.1016/0009-2509(74)80124-7

1873-4405

John W. Chapman, P.R. Cox, Alec N. Strachan,

Catalytic Processes in Materials Science

Initial nitration rates of toluene have been measured at sulphuric acid strengths between 76 and 79 per cent in a stirred cell with pure toluene, and also in a stirred batch reactor with a dilute solution of toluene in an inert solvent. The results are consistent with the rates in both cases occurring within the transition from the slow to the fast reaction diffusional regime. With the stirred reactor and diluted toluene reasonable values of 44·cm−1 and 1·03×10−3 cm sec−1 are obtained for the interfacial area per unit volume of the acid phase and the overall mass transfer coefficient, respectively. However, when the organic phase is pure toluene, both stirred cell and stirred reactor rates are lower than expected. The conclusion is drawn that the formation of nitronium ions, rather than their attack on the toluene, is the rate limiting kinetic step under these conditions. The rate constants for the formation of nitronium ions from nitric acid in 78·45 per cent sulphuric acid is estimated to have the value 0·40 sec−1 at 25°C.