Hydrocarbon present in petroleum (7)
I believe the answer is:
toluene
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hydrocarbon present in petroleum</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for toluene that I've seen before include "Compound" , "flammable liquid" , "Hydrocarbon present in petroleum" , "Constituent of petroleum" , "One lute (anag.); a solvent" .)