D - Glucose Acid Salt Synthesis, Crystal Structure And Thermal Chemical Research

D-glucose is one of the most important and basic nutrients to maintain the normalphysiological functions for human. And inorganic metal ions such as Na+, K+, Ca2+andMg2+no only maintain the fluid acid-base balance, but also have an important influence onthe growth and development of the body. There is an aldehyde in the D-glucose molecule,which is easily oxidized to D-gluconic acid. In recent years, as an important nutritionalsupplement, D-gluconate is very easy to be absorbed by the body and is paid attention bypeople because it is no toxic and side effect. However, the crystal structures of these kindcompounds and their thermodynamic properties have not been reported in the literatures.In order to develop wide application and new further theoretical study of D-gluconates, themain works of this thesis are as follows:1. Seven D-gluconates were synthesized. The compositions and spatial structures of thecompounds were characterized by element analysis、chemical analysis and X-raysingle crystal diffraction technique.2. Lattice potential energies of the seven D-gluconates (crystalline compounds) weredetermined from data of the crystal structures. The volume of unknown cation or anionwas calculated.3. The heat capacities of the seven compounds have been measured by a precisionautomatic adiabatic calorimeter in the temperature range from78to400K. The resultsshowed that no endothermic peaks occurred in the heat capacity curves in themeasured temperature range. The adiabatic calorimetric experiments have revealedthat the structures of seven compounds were stable in the measured temperature range.4. The experimental heat capacities for each of the compounds were fitted by theleast-squares method and one polynomial equation of experimental molar heatcapacities vs. reduced temperature has been obtained. The smoothed molar heatcapacities and thermodynamic functions of these compounds relative to the standardreference temperature298.15K were calculated based on the fitted polynomialequations.5. A thermochemical reaction, in which target compound was used as one of the products, was designed on the basis of Hess’s law. A suitable solvent was chosen and theenthalpies of dissolution of the reactants and products of the reaction were measuredusing isoperibol solution-reaction calorimeter. Then the enthalpy change of thesupposed reaction can be determined. The standard molar enthalpies of formation ofthe compounds were derived from the combination of the enthalpy change of thereaction with other auxiliary thermodynamic data. In addition, the data of therefractive indexes were used to confirm the reliable and reasonable of the designedHess thermochemical reactions.6. According to Pitzer’s electrolyte solution theory, the molar solution enthalpy ofD-gluconates in water at infinite dilution (sH m) and Pitzer’s parameters wereobtained at298.18K.