Adsorption of liquids and swelling of wood - IV. Temperature dependence onthe adsorption

For the purpose of understanding the swelling phenomenon of wood in liquids , the contributions of enthalpic and entropic terms to the standard free en ergy change of adsorption have been determined by measuring the temperature dependence of adsorption isotherms. The Values of standard enthalpy change of adsorption are smaller for alcohols having both proton-accepting and -d onating properties than for acetone having only a proton-accepting properly . The results are discussed in terms of the proton-accepting power and the cohesive energy of the respective adsorbate liquids. Methanol showed a larg er iso steric heat of adsorption to dried wood than to pre-swollen wood, an d the amounts of methanol and acetone adsorbed on dried wood exceeded those on swollen wood within the low activity range. These results indicate the presence of more exothermic sites in dried wood than in pre-swollen wood, a nd of pre-existing spaces and/or parts loosely hydrogen-bonded between wood constituents in the cell walls of dried wood.