Studies On The Low Temperature Thermodynamic Properties Of Monosaccharide And Thermal Decomposition Kinetics

Saccharide is not only one of the basic substances of life-sustaining activities, is also a main source of energy in human foods. It is up to the content of organic compounds in nature. The early 1960 s, the study of saccharide is gradually increasing because of its unique biological functions. Then, organic chemists and biologicals on saccharide structure, synthesis and biological function conducted extensive studies it has been rapid development. Therefore, with a deeper understanding and become more active in various research field. Present, saccharide is widely used in food, organic synthesis and biochemical research and other fields. But, the study of thermodynamic properties of the saccharide is still insufficient.This paper have reported that the heat capacities of D-glucose, D-fructose, D-galactose, D-mannose and D-ribose were measured using a Quantum Design Physical Property Measurement System(PPMS) over the temperature range from T =(1.9 to 300) K, and the experimental data were fitted to a function of T using a series of theoretical and empirical models for appropriate temperature ranges. The results of these fits were used to calculate thermodynamic function values from T =(0 to 300) K. The standard molar entropy of D-glucose, D-fructose, D-galactose, D-mannose and D-ribose at 298.15 K were determined to be(214.64±0.21)J·K-1·mol-1、(217.56±0.21)J·K-1·mol-1、(211.22±0.21)J·K-1·mol-1、(217.51±0.22)J·K-1·mol-1、(181.23±0.18)J·K-1·mol-1, respectively. Analysis and comparison of its heat capacity, and use the TGA investigate the thermal stability.It can be seen that the heat capacities of these compounds increase with the temperature increasing and no any phase transitions or other anomalies can be found, suggesting that D-glucose, D-fructose, D-galactose, D-mannose and D-ribose are thermodynamic stable in the entire experimental temperature region. The heat capacity of six-carbon saccharide(D-glucose, D-fructose, D-galactose, D-mannose) is always lager than that of D-ribose due to the larger molecular weight of six-carbon saccharide. By thermal analysis, under a nitrogen and air atmosphere, D-glucose, D-fructose, D-galactose, D-mannose and D-ribose experience the same thermal decomposition process.This work not only deepen the understanding of the D-glucose, D-fructose, D-galactose, D-mannose and D-ribose, but also for its practical application in the bio-manufacturing, medical research and other fields to provide accurate, efficient thermodynamic data support, is a very meaningful work.