摘要
以维生素C及常用于其注射液中作稳定剂的焦亚硫酸钠为例,测定了两组平行反应(维生素C无氧降解和有氧降解;维生素C和焦亚硫酸钠的氧化反应)的动力学参数,建立了维生素C的降解动力学方程.结果表明维生素C无氧降解为零级反应;在维生素C和焦亚硫酸钠的氧化反应中,维生素C和焦亚硫酸钠的反应级数都为零,溶解氧为一级;维生素C溶液的吸光度变化在一定范围内和浓度降解量成线性关系.根据建立的动力学方程,从理论上计算得在维生素C溶液中加(或不加)焦亚硫酸钠时的贮存期分别为444 d(或152 d),表明加入焦亚硫酸钠能显著延长维生素C溶液的贮存期.
The rates of two sets of parallel reactions, the degradation reactions of ascorbic acid under both anaerobic and aerobic conditions and the oxidation reactions of ascorbic acid and sodium metabisulfite, were investigated. The results show zero-order for the degradation of ascorbic acid under anaerobic conditions; zero-order with respect to ascorbic acid and sodium metabisulfite for the oxidation reactions of ascorbic acid and sodium metabisulfite, respectively; and first-order with respect to the oxygen concentration in solution. A plot of absorbency versus the total concentration drop of ascorbic acid yields a straight line. The shelf-life of ascorbic acid solution calculated was 444 d （or 152 d） with （or without） sodium metabisulfite, indicating that sodium metabisulfite increases the stability of ascorbic acid significantly.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2009年第6期459-465,共7页
Acta Chimica Sinica
基金
国家自然科学基金(No.30472104)资助项目
关键词
维生素C
焦亚硫酸钠
速率常数
反应级数
贮存期
ascorbic acid
sodium metabisulfite
rate constant
reaction order
shelf-life
