全乙酰基-β-D-吡喃半乳糖的超声溴化反应动力学

Ultrasonic Brominatin Reaction Kinetics of Penta-O-Acetyl-β-D-Galactopyranose

运用薄层色谱扫描技术研究了回流温度时(76°C)1,2,3,4,6-五-O-乙酰基-β-D-吡喃半乳糖的超声溴化反应,通过测定反应液中初始物半乳糖的浓度随超声辐照时间的变化,采用一次法和初速度法分别建立了该反应的反应动力学方程:r=9.348×1-0 31ρ(一次法),r0=1.07 8×1-0 21ρ,0(初速度法),确认这一反应对初始物半乳糖为一级反应,探讨了可能的反应机理,根据推测的反应机理得到的动力学方程为r=K1ρ,(K=2k1k2ρNBSk5),与实验结果一致。

ultrasonic bromination reaction of 1,2,3,4,6-penta-O-acetyl-β-D-galactopyranose at reflux conditions（76℃） was studied by thin layer chromatography scanning. With the flooding method and the initial rate method, the sonochemical reaction kinetic equation was set up by the relation between the concentration of the galactopyranose and the time of ultrasonic irradiation. The kinetic equation is expressed as r=9.348 ×10^-3ρ1 （the flooding method） or ro = 1.078 × 10^-2ρ1、0 （the initial rate method）. The rate order is 1 for galactopyranose. The mechanism of the reaction was proposed, and the kinetic equation in theory according to hypothetical mechanism is expressed as r=Kρ1, （K=2 k1 k2 ρNBS —— k5 ）, which is in accordance with the result of the dynamic experiment.