D-葡萄糖D-果糖与硼的有机物形成配合物的稳定性研究

STUDY OF THE STABILITY OF THE COORDINATION COMPOUNDS OF D-GLUCOSE OR D-FRUCTOSE WITH BORON ORGANIC COMPOUNDS

葡萄糖异构酶加速葡萄糖与果糖的平衡,平衡时果糖含量为42％左右,体系中加入一些硼酸盐,果糖的含量提高到80％左右,究其原因可能是由于葡萄糖和果糖与硼酸盐形成不同稳定性的配合物。虽然Roy,Conner,Daris,Belcher,Lorand等都已报导了这些配合物的稳定常数,概括结果分歧较大。

The coordination numbers and the stability constants of the coordination compounds formed from D-glucose or D-fructose with boric acid or benzeneboric acid have been determined respectively by using pH method under different temperatures. Meanwhile, we obtained also further standard free energy changes △G° , standard enthalpy changes △H° and standard entropy changes AS ?for the above mentioned coordination reactions. The experiment results show that the stability constants of coordination compounds of D-fructose with boric acid or benzeneboric acid are much greater than those of D-glucose with corresponding boric acids ( about 300 times, 25℃ in boric acid ). This makes isomerization equilibrium move to the fructose formation direction. This paper also studied the influence of solvent upon the stability of the above mentioned coordination compounds. A catalytic mechanism for the isomerization reaction of D-fructose in boric acid or benzeneboric acid has been suggested.