Sulfur-containing molecules interaction with

Interaction of Zeolites with Sulfur-Containing Molecules... 

An enormous amount of work has been done in this wide field and a number of excellent reviews on different aspects of sulfur electrochemistry has been published [1-7], so here we confine our attention to some principal reactions and interesting apphcations of both anodic and cathodic activation of sulfur-containing molecules. Compared to other chalco-genides, sulfur has frontier orbitals that have volume, symmetry, and energy more suitable for efficient interaction with adjacent carbon atoms. The ionization of molecular sulfur requires about 10 eV. Conjugation of the pz orbitals of sulfur with a 7T-system lowers the ionization potential by ca. 2 eV. For this reason, compounds of divalent sulfur undergo oxidation rather easily often giving rise to cation radicals or dications. The stability of this species is in line with the... 

Barbour and Petersen (1974) observed strong H-bonding basicity of asphaltenes with phenol, having enthalpy of interactions between 6 and 8 kcal/mole. Phenol-base interactions for ir aromatic bases are typically as low as 0.5 kcal/mole but can reach 9 kcal/mole for nitrogen- or sulfur-containing molecules (Barton et al., 1972 Osawa et al., 1967 Whetsel, 1968). 

When simulating the interaction of amino acids with a silica surface in a biological medium, the zwitterionic form as well as hydration should also be taken into consideration.12 Shielding of functional groups (amino, carboxyl, and thiol) of sulfur-containing amino acid molecules by water molecules results in... 

When adsorbed from the gas phase sulfur-containing acids form the most stable neutral complexes, whereas a similar process in solution is accompanied by rearrangement into a zwitterionic structure. It should be noted that adsorbed cystine molecules preserve their disulfide bridges, indicating that their native structure remains under interaction with the silica surface. 

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