prep. of nitrobenzene - lets say temp used is about 55 degrees c, what other produts would form if higher temp

Question

nitrobenzene is produced from a reaction mixture of conc. sulphuric acid and conc. nitric acid, which give rise to the nitronium ion. so by electrophilic substituion into the benzene ring, nitrobenzene is produced. if this reaction mixture was heated, what other products beside nitrobenzene would be produced? thnx.

Answer 1

Once you make nitrobenzene, the nitro group will be withdrawing electron density from the benzene ring making a dinitro product less likely. However, if you heat it and push it you will form some dinitro products. The nitro group's resonance structures show that the presence of one nitro group will make further electrophylic substitution in the meta position. You would make m-dinitrobenzene. It would take a lot of work to make 1,3,5 - trinitrobenzene because the dinitro product would have markedly reduced the ring's electron density.

Answer 2

The nitro group deactivates the benzene ring, but if you push the reaction it will still allow reaction to take place. Being that the nitro group is an meta director the other product expected is 1,3-dinitrobenzene.

ref: http://www.chemguide.co.uk/organicprops/arenes/nitration.html

Answer 3

At higher temperature dinitro and trinitro benzene will be produced.