HEATS OF ADSORPTION OF SMALL MOLECULES ON VARIOUS FORMS OF LACTOSE, SUCROSE, AND GLUCOSE

The heats of adsorption of a variety of organic compounds were determined by the gas chromatographic method on regular, anhydrous a-lactose (r-lactose), β-lactose, anhydrous α-D-glucose, and sucrose and compared with heats of adsorption previously determined for stable, anhydrous a-lactose (s-lactose). r-Lactose showed greater heats of adsorption than s-lactose for all compounds studied except for formate esters. All compounds studied except the hydrocarbons showed larger heats of adsorption on β-lactose than on s-lactose. Heats of adsorption on β-lactose were generally greater than those on r-lactose. Sucrose showed much lower heats of adsorption than the three lactoses. Anhydrous β-D-glucose generally showed greater heats of adsorption than s-lactose and were of the same order as those for r-and β-lactose. The bonding mechanisms appear to be similar to those proposed for s-lactose. Gibbs energies and entropies were calculated for all lactose reactions studied. © 1979, American Chemical Society. All rights reserved.