ISSUE:

Good morning,
in the 0º nitration of toluene I obtain 65% o nitrotoluene and yun 30% p nitrotoluene with some m nitrooluene, what conditions would be necessary to obtain p nitrotoluene as the majority product?
All the best

Hi Forumer.
If your starting material is toluene, you have to make the methyl group of it increase in volume without losing its ortho-para orienting effect. In this way, the subsequent nitration will be almost exclusively in the para position and then you regenerate the methyl group .
Greetings

...how is this possible?.....

Hello Forero

The fundamental work of a chemist is the preparation of compounds or molecules in organic chemistry, free of isomers. This challenge leads to seeing various options, which can often be more expensive than separating the isomers. Many times the process has to be accepted and that is why in the synthesis of drugs, we have very expensive molecules.
I suggest two alternatives:
Alternative A:


Alternative B:


Greetings