Variable-temperature FTIR spectroscopy

VARIABLE TEMPERATURE FTIR SPECTROSCOPY IN THE STUDIES OF SURFACE PHENOMENA... 

Infrared spectroscopic studies have shown that adsorbed carbon monoxide interacts with Brensted acid Si(OH)Al groups of the zeolite H-ZSM-5 forming hydrogen-bonded H-CO and H—OC species, which are characterized by C-0 stretching IR absorption bands at 2175 and 2112 cm", respectively. By means of variable-temperature FTIR spectroscopy, these C-bonded and O-bonded adducts were found to be in a temperature dependent equilibrium which can be described as ZH CO = ZH- OC, where Z stands for the zeolite framework. The corresponding enthalpy change was found to be AH° = 4.2 kJ mol", as derived from a van t Hoff analysis of the intensity of the corresponding IR absorption bands as a function of temperature. 

In this context, diffuse reflectance FTIR spectroscopy has been applied to analyze the influence of mixing variables (i.e. treatment concentration, time and temperature of mixing) on both the ultimate flller coating level and possible reaction between the treatment and flller surface [127]. 

See Silicon-aluminum interactions in biology Alzheimer s disease, role of aluminum, 606 Amine desorption, variable-temperature diffuse reflectance Fourier transform infrared (FTIR) spectroscopy from siliceous surface, 257-266 Amine-stabilized sol, manufacturing... 

SSNMR spectroscopy. However, FTIR and Raman spectroscopy, thermal microscopy, variable-temperature x-ray diffractometry (VTXRD), and DSC may also be used to identify polymorphs. Solvates may be similarly characterized by the techniques mentioned above. In addition, the stoichiometric number of the solvent molecules in the crystal lattice of solvates may be determined by thermogravimetric analysis (TGA), gas chromatography, or, in the case of a hydrate, by Karl Fiseher titrimetry [37]. 

Figure 2-44. (a) Principle of rheo-optical FTIR spectroscopy of polymer films, (b) Variable-temperature stretching machine for rheo-optical FTIR and FT-Raman spectroscopy. (A) stretching machine (B) sample transfer mechanism (1) stress transducer (2) strain transducer (3) film sample (4) sample clamps [17, 18]. 

Energetic materials are usually used as mixtures of several components. Since Temperature Profiling/FTIR Spectroscopy [93] permits several variables of the thermal decomposition process to be measured simultaneously, useful data on decomposition synergism among the components might be extracted with this technique. 

Raman spectroscopy with variable temperature accessories has been valuable for probing phase transitions within solid-state pharmaceutical samples. In combination with other techniques [x-ray diffractometry, solid-state nuclear magnetic resonance (NMR), FTIR spectroscopy, and thermal analysis], the molecular basis for thermal transitions between dihydrates of carbamazepine prepared from different polymorphs of the drug were re-... 

Figure 4-7. Evolution of FTIR spectra for coatings prepared from TEOS (IS) and MTES/TEOS (HS) at normal incidence, for different heat treatment temperatures. (Reprinted from Journal of Non-Crystalline Solids, 298, J. Gallardo, A. Duran, D. Di Martino, R.M. Almeida, Structure of inorganic and hybrid Si02 sol-gel coatings studied by variable incidence infrared spectroscopy , p. 220, Copyright (2002), with permission from Elsevier.)...

Infrared spectra were obtained using potassium bromide pellets employing an Alpha Center FTIR. Mass spectroscopy (DIP) was carried out employing a Kratos MS-50 Mass Spectrometer operating in the El mode, 8 KV acceleration and a ten second per decade scan rate with variable probe temperature (Midwest Center for Mass Spectrometry, Lincoln, Nebraska) and a DuPont 21-491 Mass Spectrometer at 1.8kv. Elemental analysis was carried out by Galbraith Labs. (Knoxville, TN). Solubilities were determined by placing about 3 mg of sample in approximately 5 mL of liquid. 

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