Oxidative cracking of three to five-member ring polycyclic aromatic hydrocarbons in subcritical and supercritical water

•PAH react fast with sub-stoichiometric O2 amounts in sub and supercritical water.•Batch reactor experiments enabled tracking reactions along a fast heating curve.•Oxidation occurs preferentially in PAH central rings.•Addition of oxygen weakens the rings promoting subsequent cracking.•SCW stabilised cracking products but SubCW favoured condensation reactions.