Co-salen Biomimetic System Component Of The Study Of The Mechanism Of Action

With the concern of people for environmental protection and the improvement of environmental awareness, the development of "environmentally friendly pulp bleaching technology, implementing green chemistry" is becoming more and more important. For the requirement of developing low impact bleaching technology, many researchers are committied to developing bleaching agents which are cleaner and more environmental, such as microorganisms,enzymes and biomimetic system.and so on. Biomimetic catalyst has characteristics of both enzymatic catalyst and chemical catalyst. Therefore, it is an efficient approach of green chemistry. The Co-salen complex in this paper is a biomimetic catalysis.Due to the complex structure of natural lignin, it is difficuclt to master the main fracture modes of some chemical bonds during reaction process of natural lignin. In order to simplify research means, we used lignin model compounds as an alternative for nature lignin.Co-salen biomimetic system studied was composed by Co-salen complex, pyridine, NaOH, H2O2 and O2. In this paper, the effects of compositions in biomimetic system were studied using FTIR,13C-NMR and GC-MS based on the structural changes and degradation products of lignin model polymers. Co-salen catalysed the cleavage ofβ-O-4 linkages and the proceeding of oxidative reaction; pyridine enhanced the cleavage ofβ-O-4 linkage, the degradation of side-chains, the opening of aromatic rings and the formation of phthalic acids and esters; Sodium hydroxide promoted the cleavage ofβ-O-4 linkages, the degradation of aliphatic ethers and side-chains, the formation of phenolic hydroxyls and the reactivity of lignin models; Hydrogen peroxide accelerated the cleavage ofβ-O-4 linkages, the degradation of aromatic ethers and aliphatic groups, the demethoxylation and the formation of phenolic hydroxyls; Molecular oxygen accelerated the ring-opening, the degradation of aliphatic side-chains and aromatic-and aliphatic-ethers, the cleavage ofβ-O-4, the demethoxylation and the formation of phenolic hydroxyls and oxygen-containing compounds such as phthalic acids, esters and acetophenones.