玉米芯酶解残渣酚化改性工艺及产物结构表征

以玉米芯纤维素酶水解残渣为原料,利用对甲酚和硫酸对其木质素进行酚化改性。采用单因素和正交试验的方法探讨了硫酸浓度、反应温度、反应时间和硫酸用量对酚化改性产物的得率、酚―羟基含量的影响。利用FTIR、1H-NMR和GPC等手段对酚化木质素的结构进行表征。研究结果表明,酚化改性可以有效地提高木质素的酚羟基含量,降低木质素大分子的分子量。正交实验结果表明,反应温度对酚化改性的影响最大,其次是硫酸浓度,酚化改性的最佳工艺条件为:温度40℃,硫酸质量分数60%,时间60 min,硫酸用量20 mL/g(残渣),此条件下木素酚得率达53.85%,酚羟基含量为1.23 mol/C9,相对分子质量(w M)为3388。

Technology Conditions for the Phenolation of Enzymatic Corncob and Structural Characterization

Lignophenol was prepared through a phase-separation system composed of p-cresol and sulfuric acid using the residues of enzymatic hydrolysis corncob. The effect of different factors including sulfuric acid concentration, reaction temperature, reaction time and the dosage of acid on yield and phenolic hydroxyl content of lignophenol were investigated. The structure of lignocresol was characterized with FT-IR, 1H-NMR and GPC. The results indicated that the content of phenolic hydroxy group could be improved efficiently; the molecular weight was obviously decreased. The results of orthogonal experimental indicated that the reaction temperature was the most important factor and the sulfuric acid concentration took the second place. The optimum conditions of lignophenol preparation are： temperature 40℃, concentration of sulfuric acid 60%, reaction time 60 min, dosage of acid 20 mL/g （based on residue）, yield of lignophenol is 53.85%, content ofph-OH is 1.23 tool/C9 and relative molecular weight （Mw） is 3 388.