Abstract
This study seeks to determine, and perhaps explain in terms of structure, some of the thermodynamic properties of a closely related set of carbohydrate compounds. The data sought in this connection are as follows: 1. Heats of combustion 2. Heats of solution 3. Heats of sublimation From these data, heats of formation of the crystalline materials, of the compounds in aqueous solution and of the gaseous compounds can be obtained. The heats of aqueous solvation for the compounds going into solution from the gas phase also can be obtained. The compounds of immediate interest are the pentoses, (α-arabinose, β-lyxose, α-xylose, ribose), β-2-deoxyribose, α-methyl xylopyranoside and β-methyl xylopyranoside. The purity of the samples was investigated using gas chromatography of the trimethyl silyl derivatives of the compounds, α-Xylose was found to have a small amount, 4%, of anomeric impurity while ribose was found to be an anomeric mixture. Further characterization of the compounds was done by recording their x-ray powder patterns. The samples were dried at 40-50 °C over drierite in a vacuum for 24-72 hours. For less stable samples, β -2-deoxyribose and armethyl xylopyranoside, the drying time was six hours. A rotating bomb calorimeter, modified for use as a static bomb calorimeter was used for heats of combustion measurements. These compounds do not bum readily. Benzoic acid was used to help in the combustion of the samples. Pellets made from these compounds were difficult to handle without causing them to crumble..
Thomas, Raymond Hilton Percival (1978). An experimental study of the energy-structure relationships among pentose sugars and some of their derivatives. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -637798.