Thermal oxidation of cellulose investigated by chemiluminescence. The effect of water at temperatures above 100 °C

The kinetic data obtained from chemiluminescence (CL) accompanying oxidation of cellulose containing pulps were compared with those from polymerization degree determinations and mechanism of CL accompanying the oxidation of cellulose was discussed. At the same time, the CL method has been used to explore the effect of oxygen and water in a reactor allowing the humidity control. The specially designed chemiluminometer Lumipol 3 has been used for this purpose coupled with humidity control chamber. An addition of water flow to oxidized pulp sheet leads to an immediate increase of CL and to its relaxation decay. The similar phenomenon has been observed when water flow was stopped, the decay of the signal following the initial increase, however, occurred with slower kinetics. The signal increase due to wetting and drying was strongly pronounced by the presence of Mg(HCO3)2 and by the origin of the pulp sheet, and in the case of wetting, also by the total amount of water being in contact with the surface of pulp sheet.