Part of TNT (7)
I believe the answer is:
toluene
'part of tnt' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for toluene that I've seen before include "Hydrocarbon present in petroleum" , "Hydrocarbon in petrol" , "Constituent of petroleum" , "Hydrocarbon resembling benzene" , "Compound" .)