Peracetic acid has been shown to be an effective agent for the bleaching of chemical and mechanical pulps. To gain a better understanding the mechanism of delignification during pulp bleaching, the degradation by Peracetic acid of some aromatic compounds, such as vanillyl alcohol, guaiacylmethyl carbinol, vanillin, acetovanillone, vanillic acid and protocatechuic acid, was carried out in the agent solution at 35°C for a prolonged period.
The main degradation products obtained in this way were vanillin, protocatechualdehyde, 2-methoxy-p-hydroquinone and 2-methoxy-p-benzoquinone from vanillyl alcohol and guaiacylmethyl carbinol. It also appears that the formation of acetovanillone from guaiacylmethyl carbinol was accelerated in a Peracetic acid solution. On the other hand, the products, such as 2-methoxy-p-hydroquinone and 2-methoxy-p-benzoquinone were formed from vanillin and acetovanillone under the same conditions. But, the formation of protocatechiuc acid from acetovanillone by peracetic acid was not identified. The small amounts of muconic, malefic and oxalic acids were found in the all aromatic compound solutions after peracetic acid degradation.
From above results, a scheme for the main oxidative degradation by Peracetic acid of some aromatic compounds used was suggested (shown in Fig. 6).