固定化Cu(salen)-固定化Co(salen)一锅法催化降解硫酸盐木素

One-pot Catalytic Degradation of Kraft Lignin by Immobilized Cu(salen)-Immobilized Co(salen)

将固定化Co(salen)和固定化Cu(salen)应用于硫酸盐木素的一锅法催化降解中,通过硫酸盐木素降解率和单酚类降解产物含量比较不同催化条件的降解能力.与单个催化剂相比,组合使用两种催化剂一锅法催化更能有效降解硫酸盐木素,降解率更高;GC-MS检测的芳香类木素降解产物含量更大,特别是香草醛.同时,对木素结构分析的结果表明,一锅法催化促进了木素侧链的氧化和断裂,苯环的开环和降解,β-O-4、β-β、β-5连接键的断裂,甲氧基的脱除.最后,采用UV-VIS和EPR分析了催化降解木素的自由基机理.结果表明,催化降解主要是通过超氧配合物作用于酚氧自由基而产生的;一锅法催化增强了超氧配合物和酚氧自由基的产生.另外,催化反应中添加亚油酸钠能够增强木素的降解.

Immobilized Co(salen)and immobilized Cu(salen)were applied to one-pot catalytic degradation of kraft lignin,and the different catalytic conditions were compared by the degradation rate of kraft lignin and the content of monophenol degradation products.Compared with single catalyst,one-pot catalysis combining the two catalysts effectively degrade kraft lignin,and the degradation rate was higher;the content of aromatic degradation products was more according to the detection by GC-MS,especially the vanillin.At the same time,the results of structural analysis of lignin showed that one-pot catalysis promoted the oxidation and cleavage of lignin side chains,resulting in ring-opening,degradation of β-O-4,β-β and β-5 bonds,and demethoxylation.Finally,the radical reaction mechanism of lignin degradation was analyzed by UV-VIS and EPR.The results showed that the catalytic degradation was mainly caused by superoxide complexes upon phenoxy radicals,and the production of superoxide complexes and phenoxy radicals was enhanced by one-pot catalysis.In addition,the addition of sodium linoleate in the catalytic reaction can enhance the lignin degradation.