论文部分内容阅读
我们在研究Me_2SO—H_2O二元体系中糖淀粉[A]的物理和化学行为的基础上,又就溶剂组成对十二酸对-硝基苯酚酯水解行为的影响进行了研究。我们测量了硼酸缓冲液体系中五个不同φ值的k_(obs)对糖淀粉浓度的依赖关系(图1),φ值为混合溶剂中Me_2SO的体积分数~([1])。初看起来结果是复杂的,在[A]=0,即糖淀粉不存在的情况下,速度常数(k_(nn))随溶剂中Me_2SO量的增加而增加,即φ=0.5<0.6<0.7<0.8<0.9。加入糖淀粉后,曲线开始互相交叉。φ[A]>1.1×10~(-4)时,其次序几乎发生倒转,即φ=0.9<0.8<0.7<0.5<0.6。而且,=0.5,0.6,0.7的曲线随[A]增大而下
Based on the investigation of the physical and chemical behavior of starch A [Me] in Me_2SO_H_2O binary system, we also studied the influence of solvent composition on the hydrolysis of p-nitrophenol ester. We measured the dependence of k_ (obs) at five different φ values on the concentration of glycans in the borate buffer system (Figure 1). The phi value is the volume fraction of Me_2SO in the mixed solvent. At first it looks like the result is complicated. The velocity constant (k_ (nn)) increases with increasing Me_2SO content in the solvent, ie φ = 0.5 <0.6 <0.7 at [A] = 0, <0.8 <0.9. After adding starch, the curves begin to cross each other. When φ [A] is more than 1.1 × 10 -4, the order is almost reversed, that is, φ = 0.9 <0.8 <0.7 <0.5 <0.6. Moreover, the curve of = 0.5, 0.6, 0.7 increases with [A]