Title: Thermochimica Acta

Title: Thermochimica Acta

ISO Abbreviated Title: Thermochim. Acta

JCR Abbreviated Title: Thermochim Acta

ISSN: 0040-6031

Issues/Year: 22

Journal Country/Territory: Netherlands

Language: Multi-Language

Publisher: Elsevier Science BV

Publisher Address: PO Box 211, 1000 AE Amsterdam, Netherlands

Subject Categories:

Chemistry, Analytical: Impact Factor 1.417, 35/68 (2006)

Chemistry, Physical: Impact Factor 0.807, 67/91 (2000); Impact Factor 1.417, 68/108 (2006)

Van Bokhoven, J.J.G.M. (1979), A method to measure the net heat of adsorption and the adsorption isotherm simultaneously. Thermochimica Acta, 34 (1), 109-126.

Full Text: T\The Act34, 109.pdf

Abstract: A new method is described to measure net differential heats of adsorption; it is applied to the adsorption of water vapour on active carbon and synthetic zeolite samples. The method seems equally appropriate for many other systems. By compensating the heat of adsorption instrumentally with the heat of condensation during an adsorption process, it is possible to measure directly the net differential heat of adsorption.

Amounts adsorbed are also measured calorimetrically, while the pressure is registered simultaneously. The method may be operated in either a stepwise or a continuous dosing mode. A procedure is given to derive from the experimental data (adsorption isotherm and differential heat of adsorption) the differential entropy and energy of adsorption.

Dollimore, D. (1980), The effect of heat treatment on the adsorption properties of solids. I. Introduction. Thermochimica Acta, 38 (1), 1-14.

Full Text: T\The Act38, 1.pdf

Abstract: The use of various parameters calculated from the adsorption isotherm to follow the thermal treatment of solids is outlined. The parameters include the variation in the BET-C constant, the calculation of the apparent pore volume, the average pore radius and the pore size distribution. It is pointed out that the actual character of the adsorption isotherm can be altered by the heat treatment process. Three mechanisms of heat treatment are considered, namely, sintering, gasification of solids, and the thermal decomposition of crystals. The manner in which the specific surface area may be related to these processes is described.

Dollimore, D., Spooner, P. and Turner, A. (1980), The effect of heat treatment on the adsorption properties of solids. II. The effect of heat treatment on the character of the adsorption isotherm. Thermochimica Acta, 38 (1), 15-26.

Full Text: T\The Act38, 15.pdf

Abstract: In this study the nitrogen adsorption isotherms of heat-treated zinc oxalate, sintered magnesium oxide, and some oxidised pitch resins are considered. It is shown that characterisation of the adsorption isotherm can be via the monolayer capacity, the BET constant C, or plots of the degree of coverage of the surface at various relative vapour pressures. These parameters are critically assessed and shown to be dependent upon the closeness to the manner in which the complete adsorption isotherm is described by the BET equation. In considering the complete adsorption isotherm it is considered best to characterise the adsorption data by quoting the statistical monolayer capacity and the value of C at this point on the adsorption isotherm. The adsorption isotherms are then best compared by plotting as the number of statistical layers against the relative pressure. The further characterisation by plotting the apparent variation in C or the degree of coverage of the surface against the relative pressure has a usefulness if the limitations of the method are noted.

Spiewak, B.E. and Dumesic, J.A. (1998), Applications of adsorption microcalorimetry for the characterization of metal-based catalysts. Thermochimica Acta, 312 (1-2), 95-104.

Full Text: T\The Act312, 95.pdf

Abstract: Microcalorimetry is a useful tool for studies of heterogeneous catalysts, because it provides a direct measurement of the strength with which molecules interact with solid surfaces. The following communication reviews adsorption microcalorimetric studies of unsupported metals and metal-based catalysts performed over the last 20 years, and then presents three advanced microcalorimetric techniques and their applications to the study of low surface-area-metalsingle crystals, films and powders, and metalsurfaces/catalysts that are highly reactive toward oxygenates.

Guil, J.M., Masiá, A.P., Paniego, A.R. and Menayo, J.M.T. (1998), Energetics of H₂ and O₂ adsorption on Ir/-Al₂O₃ and Ir/SiO₂ catalysts, dependence on support and on metal particle size. Thermochimica Acta, 312 (1-2), 115-124.

Full Text: T\The Act312, 115.pdf

Abstract: The adsorption of hydrogen and oxygen on Ir/SiO₂ and Ir/Al₂O₃ catalysts of various metal lic percentages and different metal particle sizes has been studied by adsorption microcalorimetry. The hydrogen adsorption stoichiometries lay between 1.1 and 2.4, depending on the support and on degree of dispersion. The variation of hydrogen adsorption heat with amount adsorbed revealed significant differences in surface heterogeneity between the various samples. The dependence of hydrogen adsorption stoichiometry and differential heat of adsorption vs. coverage curves on support and on particle size may be related to crystallite size and shape, and to differences in metal-support interaction. On the contrary, oxygen adsorption stoichiometries and differential heat of adsorption vs. coverage curves were very similar for all samples. The amount of oxygen adsorbed at the completion of the monolayer, clearly identified in the differential calorimetric isotherms, coincided with the amount of superficial iridium as determined by a volumetric method.

Matas, A.J., Cuartero, J. and Heredia, A. (2004), Phase transitions in the biopolyester cutin isolated from tomato fruit cuticles. Thermochimica Acta, 409 (2), 165-168.

Full Text: T\The Act409, 165.pdf

Abstract: The specific heat of isolated tomato fruit cuticles and their corresponding cutins have been measured by first time for the physiological temperature in the range of 0–55 °C. Variation of specific heat of the different isolates during fruit growth have been also measured. Isolated cuticles and cutin from young tomato fruits presented a clear glass transition temperature around 23 °C. Water sorption on cutin samples shifted the glass transition temperature to 16.3 °C indicating a clear plasticization of the biopolymer. The presence of these second-order transitions in these lipophilic plant material that act as a molecular barrier between the atmosphere and the plant cell, determine the mechanical and rheological properties of this biological barrier modulating the mass transfer between the environment ant the plant cell.

Keywords: Plant Cuticle, Plant Cutin, Glass Transition, Rheological Properties

Lima, I.S. and Airoldi, C. (2004), A thermodynamic investigation on chitosan-divalent cation interactions. Thermochimica Acta, 421 (1-2), 133-139.

Full Text: T\The Act421, 133.pdf

Abstract: The alpha-form of the biopolymer chitin, with particle sizes in the 80-200 mesh range was deacetylated under hot alkaline conditions to yield chitosan. These biopolymers were characterized by nitrogen elemental analyses, infrared spectroscopy, X-ray diffractometry and carbon-13 NMR. The degree of deacetylation found was 80.5%, which was determined via infrared spectroscopy. Chitosan suspended in water adsorbs the divalent cations cobalt, nickel, copper and zinc, as represented by batch process isotherms, in which the number of moles adsorbed as a function of cation concentration gave a defined isotherm for each cation, indicating saturation of the available nitrogen centers on the organic polymeric chain by cations in an acid-base interaction. The cation-biopolymer interaction was quantitatively followed through calorimetric fitration, whose values enabled the calculation of the thermodynamic values. The exothermic enthalpy, the negative Gibbs free energy and the positive entropic values are in agreement with a favorable thermodynamic condition for cation-chitosan amine group interaction. Based on negative enthalpic values, -26.66  0.05, -27.58  0.03, -39.05  0.01 and -27.71  0.04 kJ mol^-1, the sequence expresses the Irving-Williams series, Co < Ni < Cu > Zn. (C) 2004 Elsevier B.V. All rights reserved.

Keywords: Chitosan, Chitin, Coordination, Adsorption, Thermodynamics, Atomic-Absorption-Spectrometry, Metal-Ion Enrichment, Enzyme Immobilization, Copper Adsorption, N-Deacetylation, Chitin, Derivatives, Acid, Preconcentration, Behavior

Bausach, M., Krammer, G. and Cunill, F. (2004), Reaction of Ca(OH)₂ with HCl in the presence of water vapour at low temperatures. Thermochimica Acta, 421 (1-2), 217-223.

Full Text: T\The Act421, 217.pdf

Abstract: The final products of the reaction between HCl and Ca(OH)₂ can be Ca(OH)Cl, CaCl₂, or both simultaneously depending on the temperature, HCl concentration and reaction time. A possible mechanistic pathway consistent with the experimental results concerns two consecutive reactions: The formation of Ca(OH)Cl and the final formation of CaCl₂ from the reaction of Ca(OH)Cl with HCl. However, the second reaction might take place only, when Ca(OH)₂ is missing. The amount of water retained by the solid during the reaction between HCl and Ca(OH)₂ reaction is determined at 120 °C and 18% relative humidity employing a thermogravimetric analyser. The amount of water retained is a measure for the tendency of the solid to agglomerate. The stability of the Ca(OH)Cl at ambient conditions is studied and found to be good.

Keywords: Thermogravimetric Analyzer, In-Duct Dry Sorbent Injection, Desulfurisation, Hydrogen Chloride

? Cestari, A.R., Vieira, E.F.S. and da Rocha, F.C. (2005), Kinetics of interaction of hardened oil-well cement slurries with acidic solutions from isothermal heat-conduction calorimetry. Thermochimica Acta, 430 (1-2), 211-215.

Full Text: T\The Act430, 211.pdf

Abstract: The kinetics of interaction of hydrochloric acid with oil-well cement slurries treated with the silane coupling agents, tetraethyl orthosilicate, 3-(trimethoxysilyl)-1-propanethiol and 3-(chloropropyl)-trimethoxysilane have been investigated isothermal heat-conduction calorimetry at 298.15K. The Avrami kinetic model gives a better fit to the experimental data than the traditional Lagergren kinetics models. A pore diffusion model suggests acid diffusion only for the standard slurry. The results indicate that isothermal heat-conduction calorimetry is suitable to evaluate the protective role of silane coupling agents on hardened oil-well cement slurries. (c) 2005 Elsevier B.V. All rights reserved.

Keywords: Hardened Cement Slurries, Silane Coupling Agents, Hydrochloric Acid Attack, Isothermal Heat-Conduction Calorimetry, Kinetic Modeling, Metal-Ions, Adsorption, Chitosan, Sorption, Dyes, Parameters, Resistance, Silica, Attack

? Vyazovkin, S., Rives, V. and Schick, C. (2010), Making impact in thermal sciences: Overview of highly cited papers published in Thermochimica Acta. Thermochimica Acta, 500 (1-2), 1-5.

Full Text: 2010\The Act500, 1.pdf

Abstract: Thermochimica Acta has been serving the thermal science community for 40 years and has now published its 500th volume. The editors provide a brief overview of the highly cited papers published by the journal. Analysis of the topics of the highly cited papers suggests that Thermochimica Acta possesses major strength in the areas of instrumentation, materials, and kinetics. (C) 2010 Published by Elsevier B.V.

Keywords: Computational Aspects, Crystallization Kinetics, Differential Scanning Calorimetry, Differential Scanning Calorimetry, DSC, Ictac Kinetics Project, Impact, Ionic Liquids, Isoconversional Methods, Journal, Kinetics, Modulated Temperature DSC, N-H Compounds, Overview, Papers, Poly(Ethylene Succinate), TGA, Thermal Analysis, Thermodynamic Properties, Thermogravimetry