物理化学学报 >> 2008, Vol. 24 >> Issue (01): 91-96.doi: 10.3866/PKU.WHXB20080116

研究论文 上一篇    下一篇

278.15-313.15 K下糖-水二元体系的介电常数

陈玉娟; 卓克垒; 康磊; 徐四姣; 王键吉   

  1. 河南师范大学化学与环境科学学院, 河南 新乡 453007
  • 收稿日期:2007-08-06 修回日期:2007-09-05 发布日期:2008-01-05
  • 通讯作者: 卓克垒 E-mail:klzhuo@263.net

Dielectric Constants for Binary Saccharide-Water Solutions at 278.15-313.15 K

CHEN Yu-Juan; ZHUO Ke-Lei; KANG Lei; XU Si-Jiao; WANG Jian-Ji   

  1. School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007, Henan Province, P. R. China
  • Received:2007-08-06 Revised:2007-09-05 Published:2008-01-05
  • Contact: ZHUO Ke-Lei E-mail:klzhuo@263.net

摘要: 测定了D-(-)-果糖、D-(+)-葡萄糖、D-(+)-半乳糖、D-(+)-木糖和D-(-)-核糖五种糖的水溶液在不同质量摩尔浓度和不同温度下的介电常数(D). 结果表明, 在一定温度下, 这些糖的水溶液介电常数对数值都随糖浓度的增大而减小; 在一定糖浓度时, 介电常数值随温度升高而减小. 果糖、葡萄糖、半乳糖和木糖水溶液的介电常数(D)随温度的变化均满足关系式: lgD=A1-B1(T-298.15), 而核糖水溶液则符合: lgD=A2-B2(T-298.15)+C2(T-298.15)2. 此外, 这五种糖的水溶液的介电常数与摩尔分数(x)满足关系式: lg(D/D0)=-B3x. 在相同温度和浓度时, 介电常数的大小顺序通常为: 水>半乳糖-水>果糖-水>葡萄糖-水≥木糖-水(而核糖较特殊).

关键词: 介电常数, D-(-)-果糖, D-(+)-葡萄糖, D-(+)-半乳糖, D-(+)-木糖, D-(-)-核糖

Abstract: The dielectric constants (D) for aqueous solutions of D-(-)-fructose, D-(+)-glucose, D-(+)-galactose, D-(+)-xylose, and D-(-)-ribose were measured at 278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15 K. Molalities of saccharides are at 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 mol·kg -1. The results indicated that the logarithmic values of dielectric constants for these saccharide-water solutions decreased with increasing molalities of saccharides and decreased also as the temperature rising. At given molalities, the relationship between dielectric constants and temperatures can be expressed by lgD=A1-B1(T-298.15) for fructose-water, glucose-water, galactose-water, and xylose-water solutions, and by lgD=A2-B2(T-298.15)+C2(T-298.15)2 for ribose-water solution. At given temperatures, dependence of the dielectric constants on the mole fraction (x) can be described by lg(D/D0)=-B3x for all five saccharide-water solutions. At given temperatures and molalities, the dielectric constants are mostly in the order: water>galactose-water>fructose-water>glucose-water≥xylose-water (there is not the order for ribose).

Key words: Dielectric constant, D-(-)-fructose, D-(+)-glucose, D-(+)-galactose, D-(+)-xylose, D-(-)-ribose

MSC2000: 

  • O645