Wet air oxidation was attempted on synthetic (mixture of plastics of variou
s compositions) and natural (cellulose substances) solid polymers. The temp
erature was maintained at 270 degrees C and the oxygen pressure varied from
0 to 2 MPa (from understoichiometric conditions to oxygen excess). No valo
rizable compounds were found, even in runs carried out under an oxygen defi
cit. Suitable conditions for the total destruction of the initial polymers
were temperatures above 270 degrees C, an excess of oxygen, and a residence
time of less than 1 h. Only such degradable compounds as acetic and benzoi
c acids are found at low concentrations. Formation of chlorine and gaseous
hydrochloric acid can be limited by adding CaCO3 as a neutralizing agent.