DETERMINATION OF THE VOLUMETRIC PROPERTIES OF DILUTE D-GLUCOSE SOLUTIONS TO 50.0 MPa AND 433.15K

Introduction: The need to model and understand reactions among aqueous organic compounds and biomolecules has led to a number of experimental studies to determine the thermodynamic properties of these compounds. Unfortunately, there is a paucity of data for important compounds at elevated temperatures and pressures (including the current known temperature limits for biological activity, 122°C [1]). The immediate goal of this research is to develop an experimentally-determined database of the thermodynamic properties of important organic molecules and biomolecules. Experimentally determined volumetric properties of aqueous solutions at elevated conditions will provide direct tests of current estimation methods and aid in the refinement of these methods. The ultimate goal of this research is to develop a thermodynamic database of aqueous organic mixtures at high temperature and pressure in order to understand the metabolic processes of thermophilic organisms and aid development of more accurate geochemical models for the origin of life in aqueous environments. Glucose is a monosaccharide important in biology as an energy source (product of photosynthesis), metabolic intermediary, and important step in cellular respiration (in prokaryotes and eukaryotes). Experimental Methods: The volumetric properties of aqueous solutions of D-glucose were obtained using Anton Paar DMA 5000 and DMA HP densimeters. The DMA 5000 can measure fluid densities at conditions up to 363.150 K and 1.00 MPa and the DMA HP external cell is capable of achieving conditions as high as 473.15 K and 70.0 MPa. An isothermal stepped-flow method was employed in all of our experiments; the vibrating tube was evacuated and dried between fluids. The fundamental equation for calculating densities of fluids by vibrating-tube densimetry is