不同催化剂双氧水氧化淀粉的转化及结晶度的比较

Effects of Different Catalysts on Conversion and Crystallinity of Oxidized Starch by Hydrogen Peroxide

为了研究催化剂(硫酸铜、硫酸亚铁)对氧化淀粉羧基质量分数及结构方面的影响,采用淀粉糊滴定法测定了两种氧化淀粉的羧基质量分数,并比较了其X射线衍射图谱和傅里叶红外光谱。试验结果为:硫酸铜氧化淀粉的羧基质量分数为0.048%,结晶度为33.76%;硫酸亚铁氧化淀粉的羧基质量分数为0.001 7%,结晶度为34.12%。试验表明:硫酸铜对双氧水的催化效果缘于硫酸亚铁;双氧水不能打破淀粉结晶结构,氧化反应主要是在非结晶区进行。

Carboxyl contents in two kinds of oxidized starch were determined in order to study the effects of different catalysts （copper sulfate and ferrous sulfate） on carboxyl content and structure of oxidized starch by hydrogen peroxide. X-ray dif- fraction spectrum and Fourier transform infrared spectrum of the two oxidized starches were compared. Result showed that the carboxyl content and the degree of crystallinity of oxidized starch in the presence of copper sulfate were 0. 048% and 33.76%, while those of oxidized starch in the presence of ferrous sulfate were 0. 001 7% and 34.12%, respectively. It is indicated that the catalytic effect of copper sulfate is better than that of ferrous sulfate. Hydrogen peroxide solution can＇ t break up the crystal structure of starch, and oxidation reaction is achieved mainly in the non-crystalline area.