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水解类植物多酚单宁酸水解后可产生葡萄糖及没食子酸 ,其水解产物葡萄糖和没食子酸 ,在一定条件下能与Cr(Ⅵ )发生氧化还原反应 ,可用于制备铬鞣剂。用光谱法模拟研究了单宁酸水解物葡萄糖和没食子酸与Cr(Ⅵ )反应发生的条件、影响其反应速率的主要因素及动力学特征 ,结果表明 :葡萄糖与Cr(Ⅵ )氧化还原反应的温度保持在 1 0 0℃ (微沸 ) ,而且当反应时间到达 3 0min以上时 ,才能达到平衡 ;Cr(Ⅵ )的浓度较酸度变化更明显地影响反应速率 ;没食子酸的反应活性较葡萄糖的反应活性高得多 ,在常温下也能较快进行 ,温度在45℃ ,反应在 5min左右可达平衡 ,还原产物主要为有机小分子酸类物质。
Hydrolysis of plant polyphenols tannin hydrolysis can produce glucose and gallic acid, its hydrolyzate glucose and gallic acid, under certain conditions with Cr (Ⅵ) redox reaction can be used for the preparation of chrome tanning agent. The main factors influencing the reaction rate and the kinetic characteristics of the hydrolysis reaction of glucose and gallic acid with Cr (Ⅵ) were studied by spectroscopic method. The results showed that glucose and Cr (Ⅵ) redox reaction The temperature was kept at 100 ℃ (micro-boiling), and when the reaction time reached more than 30min, the equilibrium could be reached. The concentration of Cr (Ⅵ) affected the reaction rate more obviously than the change of acidity. The reactivity of gallic acid was lower than that of glucose Reactivity is much higher, at room temperature can also be faster, the temperature at 45 ° C, the reaction reaches equilibrium in about 5min, the reduction products are mainly organic small molecule acids.