Study On Deoxidization Of Alkali Lignin By CuO/C Catalyst

The research is the part of the Study on Pd/C Catalyzing and Deoxidizing, imbursed by the State Nature Science Found Projects: 30471363.To improve the reaction activity of alkali lignin, the catalysis effect of CuO/C catalyst prepared by equal volume impregnation method in the deoxidization of straw alkali lignin was investigated in this paper. The chemical structure and distribution of molecular weight was analyzed by FTIR, UV,~1H-NMR and HPGPC respectively. The microcosmic morphology of CuO/C catalyst after reaction was observed by SEM.The results are as follows: the optimum conditions obtained by single factor analysis were reaction time of 2h, pH=10, 10ml of cyclohexene and 8% of CuO/C. The function group of alkali lignin was measured quantificationally through chemical methods. The result indicated that CuO/C showed an excellent catalytic activity in the deoxidization of alkali lignin. Upon the optimum condition, the content of total hydroxyl increased from 6.19% to 13.86%, while the carbonyl content reduced from 2.19% to 0.52%. HPGPC was applied to measure M_n, M_w and M_z of the refined alkali lignin and activated alkali lignin, indicating that the polydispersity of activated alkali lignin was less than the refined alkali lignin.The structural analysis showed the content of phenolic hydroxyl was stable, the total acidic increased slightly and the phenyl structure of lignin was steady. The active function group of alkali lignin was increased so the reactive activity was enhanced. That also proved CuO/C catalyst had an excellent catalytic activity in the reductive reaction of alkali lignin.The morphology of CuO/C catalyst analyzed by SEM indicated that the catalyst was distributed homogeneously on activated carbon. The catalyst was reused to study the variation of catalytic activity and the catalytic activity was reduced obviously after using for three times.