Fundamental Approach to Characterization and Processing of Coal-Derived-Liquid (CDL). Third Quarterly Report, February-May 1985

摘要

The adsorption enthlapy and entropy of over 30 compounds was measured for the gas-phase interaction of those compounds with Co-Mo/ gamma -alumina hydrotreating catalyst. Results show that enthalpy, which is a measure of the electronic interactions, decreases with increasing molecular weight, electron donating capability and molecular polarity. The molecular weight effect is thought to indicate that a multiple number of surface sites are involved as the larger the molecule is the greater the number of interactions. The fact that enthalpy decreases with molecular weight indicates that process temperature does not influence adsorption uniformly. Temperature has a relatively greater effect on the adsorption of heavy ends than the lighter ends. For aromatic compounds a good correlation is found between the enthalpy of adsorption and ionization potential of the aromatic. Entropy, which is a measure of the geometric requirements, decreases with molecular weight. Molecular symmetry also affects the entropy; in general, the more symmetrical the molecule the less change in entropy between the gas phase and the adsorbed species. A simple model relating molecular structure to adsorption is currently under development. 6 figs., 1 tab. (ERA citation 12:003305)