A Thermal Study of a Possible Source of Energy in Anaerobic Metabolism with some Notes on the Properties of Sorbitol

Abstract

The heat of combustion of dextrose in dilute solution is 3756.1 gm. calories per gm., or 676.08 calories per gm. molecule; that of gluconic acid 618.59 calories per gm. molecule, or 3151 gm. calories per gm. when oxidized completely to CO2 and water; and of sorbitol 4025 gm. calories per gm. or 732.44 calories per gm. molecule. From these figures it was shown that the auto-oxidation and reduction of dextrose to gluconic acid and sorbitol would produce only 0.57 calories per gm. molecule. This reaction is therefore rejected as a source of energy for the maintenance of life under anaerobic conditions. Little success was had in attempts to prepare sorbitol by reduction from dextrose with metallic reducing agents. The best method of purifying sorbitol is by the hexa-acetyl compound.