Comparative studies on the delignification of pine kraft-anthraquinone pulp with hydrogen peroxide by binucleus Mn(IV) complex catalysis.

摘要: Pine kraft−anthraquinone (kraft−AQ) pulp was bleached in alkaline solution with hydrogen peroxide catalyzed by either [L1Mn(IV)(μ-O)3Mn(IV)L1](PF6)2] (C1) or [LMn(IV)2(μ-O)3] (ClO4)2 (C2) at 60 and 80 °C for 120 min a catalyst charge of 10 ppm on pulp. The resulting hydrolyzed cellulase to obtain insoluble soluble residual lignins. bleaching effluents were acidified precipitate alkaline-soluble These lignin preparations then characterized 2D heteronuclear multiple-quantum coherence (HMQC) NMR spectroscopic techniques. results showed that biphenyl (5-5) stilbene structures the are preferentially degraded both C1- C2-catalyzed bleachings, whereas β-O-4, β-5, β-β undergo degradation lesser extent. In cases, increased increase reaction temperature from °C. Thus, result C1-catalyzed delignification is not i...