Publications

Abstract The standard (po=0.1 MPa) molar enthalpies of combustion at 298.15 K were measured by static-bomb calorimetry and the standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry for three benzylidene t-butylamine N-oxide derivatives and for 4-nitrobenzylidine t-butylamine: {A table is presented}. From the standard molar enthalpies of formation of the gaseous compounds, the molar dissociation enthalpies of the (NO) bonds were derived, and these were found to be constant within experimental error to give a weighted mean value: D(NO)/(kJ·mol-1) = (285.9 ± 3.6). © 1989.

Abstract The trajectory calculations of the alkali-metal atom + alkali-metal dimer reactions initiated in a previous work have been extended to the Li + Li2 system using two different potential-energy surfaces for the Li3 trimer. The results agree well with each other and with previous results by other authors, suggesting a statistical mechanism for this exchange reaction.

Abstract The behaviour of two crystal faces of gold with extreme surface energies (111) and (210) in aqueous solutions of sulphamic acid was studied. The results indicate the influence of crystallographic orientation (c.o.) in the adsorption of sulphamic acid. The degree of adsorption is intermediate between perchlorate and sulphate, and is reflected on the oxidation process of gold single crystal faces. The results are interpreted in terms of the distortion of the trigonal structure of the anion. © 1989.

Abstract The standard molar enthalpies of formation, at 298.15 K, of five crystalline bent metallocenes, [M(η-C5H5)2L] (M = Mo, W, Ti) (LH2 = 1,2-benzenediol, C6H4-(OH)2; 2,3-napthalenediol, C10H6(OH)2; 9,10-phenanthrenediol, C14H8(OH)2), have been derived from enthalpies of hydrolyses in acid solution measured by precision solution-reaction calorimetry. The results were: ΔHf° [Mo(η-C5H5)2(O26H4),c] = -130.6±2.9, ΔHf°[Mo(η-C5H5)2(O2C10H6),c] = -80.3± 2.2, ΔHf° [ Mo(η-C5H5)2(O2C14H8,c] = -53.25 ± 10.4, ΔHf° [ W(η-C5H5)2 (O2C6H4),c] = -112.8 ±2.9, ΔHf° [Ti(η-C5H5)2(O2C14H8),c] = -322.6 ± 12.7 kJ mol-1. The metaloxygen bond strengths were evaluated as mean bond enthalpy terms (E). Comparison with corresponding values in similar comlexes reveals that small steric energy arises from the binding of a catechol type ligand to a metal atom. © 1988.

Abstract The standard (po = 101.325 kPa) molar enthalpies of combustion in oxygen at 298.15 K were measured by static bomb calorimetry for the two hydroxynaphthalenes and for four dihydroxynaphthalenes. The standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry for the 1,2-, 1,3-, and 2,3-dihydroxynaphthalenes. Literature values were used for the other compounds. The standard molar enthalpies of formation in the gaseous state were derived. {A table is presented}. The standard molar enthalpies of formation of the 1,2-, 1,3-, and 1,4-dihydroxynaphthalenes in the gaseous state follow the same pattern as those for the corresponding dihydroxybenzenes. © 1988.

Abstract The adsorption of mannitol and sorbitol was studied as a function of the bulk concentration. The degree of adsorption follows the order of the solubilities of the compounds. This result is explained by overriding solute-solvent interactions since the vertical interactions of both polyalcohols with the electrode surface are similar. The effect of temperature on the differential capacity and the derived entropy of formation of the interface corroborates the idea that a water structure different from that in the bulk is responsible for the discrimination in adsorption of the small structural differences between the two solutes. Some results obtained for another isomer of sorbitol, dulcitol, are in qualitative agreement with the model proposed. © 1988.

Abstract Enthalpies of combustion and vaporization and the heat capacity have been determined for glycerol at 298.15 K. Using microcalorimeter techniques, enthalpies of solution at infinite dilution have been determined for glycerol in water (288.15, 298.15, and 308.15 K). The partial molar heat capacity of glycerol in infinitely dilute aqueous solution was derived: Cp,2∞ = (239 ± 3) J · K-1 · mol-1. This value confirms the view that the special type of interaction with water found in higher polyhydroxyl compounds is still absent for glycerol. © 1988.