Authors:Ricardo Picciochi, Hermínio Diogo, and Manuel Minas da Piedade
Combustion calorimetry, Calvet-drop sublimation calorimetry, and the Knudsen effusion method were used to determine the standard
(po = 0.1 MPa) molar enthalpies of formation of monoclinic (form I) and gaseous paracetamol, at T = 298.15 K:
were used to assess the predictions of the B3LYP/cc-pVTZ and CBS-QB3 methods for the enthalpy of a isodesmic and isogyric
reaction involving those species. This test supported the reliability of the theoretical methods, and indicated a good thermodynamic
consistency between the
The standard (pº = 0.1 MPa) molar enthalpies of formation in the condensed state of chromone-3-carboxylic acid and coumarin-3-carboxylic
acid were derived from the standard molar energies of combustion in oxygen at T = 298.15 K, measured by combustion calorimetry. The standard molar enthalpies of sublimation were obtained by Calvet microcalorimetry.
From these values the standard molar enthalpies in the gaseous phase, at T = 298.15 K, were derived. Additionally estimates of the enthalpies of formation, of all the studied compounds in gas-phase,
were performed using DFT and other more accurate correlated calculations (MCCM and G3MP2), together with appropriate isodesmic,
homodesmic or atomization reactions. There is a reasonable agreement between computational and experimental results.
The [InCl3(L)n] (where L is 2,2′-bipyridine (bipy), 2,2′-bipyridine N,N′-dioxide (bipyNO), N,N-dimethylacetamide (dma), urea (u), thiourea (tu) or 1,1,3,3-tetramethylthiourea (tmtu); n = 1.5, 3 or 4) were synthesized and characterized by melting points, elemental analysis, thermal analysis and IR spectroscopy.
The enthalpies of dissolution of the adducts, Indium(III) chloride and ligands in 1.2 M aqueous HCl were measured and by using
thermochemical cycles, the following thermochemical parameters for the adducts have been determined: the standard enthalpies
for the Lewis acid/base reactions (ΔrHθ), the standard enthalpies of formation (ΔfHθ), the lattice standard enthalpies (ΔMHθ), and the standard enthalpies of decomposition (ΔDHθ).
, Waliszewski , D . Enthalpic pair interaction coefficients in DMF solution. Part 3. Thermochemistry of NaI solutions in mixtures of N,N -dimethylformamide with urea, formamide, acetamide and N,N -dimethylacetamide at 298.15K . J Therm Anal . 1996 ; 47
Thermochemistry of crystal phase formation in vitrified municipal and hospital waste combustion ash and Ca, Fe pyroxene crystallization
mechanism are presented. Pyroxene structure is capable of accumulate heavy metals and toxicants contained in ash. Due to this
vitrification and crystallization is one of most effective method of immobilization dangerous contaminant of waste.
Authors:L. Bark, C. Bowmer, L. Kershaw, W. Moreno, and J. Openshaw
The advantages of using diodes as thermal sensors in solution thermochemistry are discussed and a simple, low-cost circuit
for the use of diodes as temperature sensors is reported. In preliminary studies, the titration of TRIS and hydrochloric acid
is used to compare the precision of thermistors and diodes in thermometric titrimetry. Several systems are assayed at various
temperatures by enthalpimetric methods to illustrate the advantages of diodes as sensors for monitoring thermal methods capable
of being used in quality control system.
Thermochemistry and structural mechanism of crystallization of MgO-Al2O3-SiO2 glasses with TiO2 as crystallization activator were studied. Thermal and HREM investigation proved that near the Tg temperature crystallization is going by rearrangement of glass structure elements and part of its components redistribution
like at disorder — order phase transition in solid bodies. Nanocrystals of Mg-titanate and high quartz structure solid solution
are formed then. Next enstatite and cordierite are crystallizing. Thermochemical and chemical bonds strength analysis indicate
that during multistage crystallization of glasses, kind and order of crystal phase formation, is determined by the glass structure
decomposition progress and its particular components release accompanying increase of temperature. It has been proved that
molar heat capacity change (ΔCp) accompanying the glass transition is the significant measure of degree of changes in the structure of glass preceding crystallization.