催化剂对双氧水氧化淀粉-锆配合物结构及鞣制性能的影响

Effect of Catalyst on the Structure of H2O2 Oxidized Starch and Its Performance as a Ligand in Zirconium Tanning

摘要:

分别用钨酸盐、偏钒酸盐和铜-铁盐等催化双氧水氧化淀粉，制得氧化淀粉配体。测定了氧化淀粉的氧化度和双氧水分解率，采用核磁共振碳谱、红外光谱和凝胶渗透色谱等分析了氧化淀粉的官能团结构和相对分子质量。考察了氧化淀粉-锆配合物的鞣制性能。铜-铁盐可催化葡萄糖单元C-2，C-3和C-6位的羟基氧化为羰基和羧基，同时打断α-1，4-糖苷键，制得低相对分子质量（14628）、高氧化度（72.5%）的氧化淀粉，用作配体可明显提高锆配合物在皮革中的分布均匀度（97.8%）和结合量（ZrO2质量分数8.0%），皮革收缩温度达89.7℃，鞣制效果最佳。钨酸盐催化氧化淀粉的相对分子质量高（465095），氧化度低（15.0%），形成的锆配合物鞣制性能差。偏钒酸盐催化氧化淀粉的性能介于上述两者之间。

Abstract:

Oxidation of starch with H2O2 was catalyzed by tungstate, metavanadate and copper-iron salts, respectively. The oxidation degree of oxidized starch and H2O2 decomposition rate were determined. The functional groups and molecular weight of oxidized starch were characterized by 13C-NMR, FT-IR and GPC. Then the tanning performance of oxidized starch-zirconium complexes was investigated. The hydroxyl groups on the C-2, C-3 and C-6 of glucose unit were oxidized to carbonyl and carboxyl groups, and the glycosidic bonds were broken during oxidation using cooper-iron salts as catalyst. This resulted in a relatively low molecular weight (14628) and a high oxidation degree (72.5%) of the oxidized starch. When it was used as a ligand of zirconium tanning agent, the Zr distribution (97.8%) and fixation (w(ZrO2)=8.0%) in leather were remarkably improved, and the shrinkage temperature of leather achieved 89.7℃, leading to better tanning performance. By comparison, tungstate catalyzed oxidized starch had a higher molecular weight (465095) and a lower oxidation degree (15.0%), and exhibited poorer tanning performance when coordinating with zirconium salt. The properties of metavanadate catalyzed oxidized starch was in between.