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Isothermal microcalorimetry, oxidation

Isoproterenol, chemiluminescence, 647 (—)-Isopulegol, artemisinin synthesis, 277, 278 Isothermal microcalorimetry, oxidation stability evaluation, 672 Isotopomers... [Pg.1470]

There are only a few reports in the literature on the use of isothermal microcalorimetry for the stability testing of pharmaceuticals (although in other fields, such as explosives, there are many more references testifying to a good degree of success). These include the degradation of P-lactam antibiotics (7), the oxidation of lovastatin (8), the hydrolysis of meclofenoxate hydrochloride (9), and the oxidation of d,l-a-tocopherol (10). [Pg.269]

Even from this limited data set, it can be seen that some processes appear to have been suitable for study by isothermal microcalorimetry (e.g., oxidation of... [Pg.269]

Willson et al. (13) note that most analytical techniques (e.g., high-performance liquid chromatography [HPLC]) look specifically for the arrival of a single product of the reaction (or loss of a reactant), and they are therefore not necessarily of value in investigations of intermediates in the reaction process, but that isothermal microcalorimetry follows the entire process (see earlier text). By comparison of calorimetric data and analytical data, it was possible to propose a sequential reaction mechanism for ascorbic acid oxidation that could not be determined simply from analytical data. [Pg.272]

The thermooxidative stability of polyamide 6 films at 100-140°C was investigated by CL/ICL and isothermal microcalorimetry (MC) techniques [617, 618]. The CL intensity in oxygen seems to be related to the content of peroxides. ICL measurements of unstabilised PA6 films denote uniform oxidation of the surface while variations in the oxidative stability of PA6/Irganox 1098 films were attributed to a non-uniform distribution of the antioxidant [617]. MC and chemiluminescence measurements were compared to oxygen uptake. All of these techniques respond to oxidation but exhibit distinctly different... [Pg.545]

In Fig. 1.21a, the differential heats of adsorption of CO on H—BEA zeolite and on MFI-Silicalite are reported as a function of the adsorbed amounts. Volumetric isotherms are illustrated in the figure inset. In both cases the adsorption was fully reversible upon evacuation of the CO pressure, as typical of both physical and weak, associative chemical adsorption. For H-BEA a constant heat plateau at 60kJ mol was measured. This value is typical of a specific interaction of CO with coordinative unsaturated Al(III) atoms, as it was confirmed by combining adsorption microcalorimetry and molecular modeling [73, 74, 78, 89] Note that the heat value was close to the heat of adsorption of CO at cus Al(III) sites on transition catalytic alumina, a typical Lewis acidic oxide [55, 73], Once saturated the Al(III) defects, the heat of adsorption started decreasing down to values typical of the H-bonding interaction of CO with the Br0nsted acidic sites (- 30 kJ mol , as reported by Savitz et al. [93]) and with polar defects, either confined in the zeolite nanopores or at the external surface. [Pg.40]


See other pages where Isothermal microcalorimetry, oxidation is mentioned: [Pg.1447]    [Pg.272]    [Pg.189]    [Pg.171]    [Pg.325]    [Pg.240]    [Pg.492]    [Pg.315]    [Pg.250]   


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Isothermal oxidation

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