THE EFFECT OF CITRATE ANIONS ON THE KINETICS OF CUPRIC ION CATALYZED OXIDATION OF ASCORBIC-ACID

被引：15
|
作者：
SAHBAZ, F
SOMER, G
机构：
[1] GAZI UNIV,DEPT CHEM,06500 ANKARA,TURKEY
[2] HACETTEPE UNIV,DEPT FOOD ENGN,06532 ANKARA,TURKEY
来源：
FOOD CHEMISTRY | 1993年 / 47卷 / 04期
关键词：
D O I：
10.1016/0308-8146(93)90175-F
中图分类号：
O69 [应用化学];
学科分类号：
081704 ;
摘要：
The kinetics of uncatalysed and Cu(II) ion-catalysed oxidation of ascorbic acid by molecular oxygen in the presence of citric acid and its anions were studied at 25-degrees-C. In the pH range investigated (2.5-6.0), the rate of cupric ion-catalysed oxidation was found to be first order with respect to ascorbic acid. The observed effects of pH and cupric ion concentration on the reaction rate suggests a mechanism which may involve the formation of a transition complex between monoascorbate ion and Cu(II)-citrate chelate. The catalytic ability is in the order Cu(II) > H3CiCu+ > HCiCu- > CiCu-2. Hydrogen peroxide was also detected during the reaction.
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页码：345 / 349
页数：5
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