Infrared spectroscopy nitrogen oxides

In applications in which FTIR does not have sufficient sensitivity, open path ultraviolet (OP-UV) spectroscopy is frequently employed. This methodology can be used for the detection of homonuclear diatomic molecules (chlorine, bromine, etc.), which have no infrared absorption, or molecules that absorb only weakly in the IR region, such as benzene, sulfur dioxide, and nitrogen oxides. 

The NO + MF, (except NO -f WF,) reactions proceed spontaneously at 20°. The reactions were followed tensimetrically. Gaseous products were identified by infrared spectroscopy and the solid products were examined by. y-ray powder-photography. Both ReF, and OsF, formed NO+[MF,] (cub.) salts and neither salt could be induced to combine with more NO to yield the quadrivalent (NO),MF, compound. In their reactions with nitrosyl fluoride at 20°, however, the rhenium and osmium fluorides are clearly differentiated ReF, readily forms a thermally stable 2 1 adduct, which is isomorphous with (NOjjWFg, whereas the OsF, -i- ONF reaction is complex. The identification of small quantities of nitrogen oxide trifluoride, in the gaseous product of the reaction, indicate the existence of an... 

Preparation of Osmium Oxide Pentafluoride.—Osmium oxide pentafluoride was made in several ways, (a) Osmium metal was heated in a stream of oxygen and fluorine (1 2 v/v). The reaction was carried out in a quartz tube with the osmium in a nickel boat, and was initiated by the heat from a small flame. Once started, the reaction sustained itself. The product, which was caught in traps at —183°, was a mixture of an emerald green solid and a pale yellow, more volatile, solid. The difference in volatility of the components of the mixture permitted their separation by trap to trap sublimation under reduced pressure, from a trap held at —16° to receivers cooled with liquid nitrogen. The emerald green solid was retained in the —16° trap. The more volatile, yellow, component proved, from its infrared spectrum, to be osmium hexafluoride. The emerald green solid, m. p. 59-2°, established by infrared spectroscopy, to be free of OsFj, amounted to —50% of the product. 

Nitrogen oxides in the flue gas were analysed continuously by a multi-component analyser based on infrared spectroscopy (Mekos). 

Chemical vapor deposition (CVD) using TiC was used to prepare Ti/Si02, Ti/MCM-41, and Ti/MCM-48 catalysts. These catalysts were characterized by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, nitrogen adsorption, and were used to catalyze the epoxidation of propylene to propylene oxide (PO) with in situ prepared ethylbenzene hydroperoxide (EBHP). CVD time and CVD temperature affected the catalyst performance significantly. The optimum temperature range was 800-900 °C, and the optimum deposition time was 2.5-3 h. The maximum PO yields obtained in a batch reactor were 87.2, 94.3, and 88.8% for Ti/Si02, Ti/ MCM-41, and Ti/MCM-48, respectively. Ti/MCM-41 had higher titanium... 

In summary, NO Os can be formed via totally different paths with different starting nitrogen oxides. However, unambiguous interpretation of the structure, stability and transformation mechanism involving this peculiar ionic species is unavailable. Therefore, comprehensive experimental means, including x-ray diffraction measurement, Raman and Infrared spectroscopy were employed to understand the fundamental properties of NO Os synthesized via the last path mentioned above. While the diffraction measurements established the P-V equation of state, the optical spectra, especially the low-temperature Raman data, elucidate important aspects of the transformation, thermodynamic properties, and stability diagram of NO Os. ... 

With the equipment described in chapter "infrared spectroscopy" the absorbance of the Pt-CO resp. Rh-CO bands on catalyst 5 resp. 6 were measured as function of temperature and oxygen partial pressure under running reaction conditions. The O/F value (ratio oxidant/fuel) was changed either by oxygen or nitrogen oxide variation. The results are shown in Fig. 13 to 17. 

Fig. 3-7. Vertical distribution of nitrogen oxides and nitric acid in the stratosphere. Left Nitric oxide in the sunlit atmosphere the fields enclose data obtained with the chemiluminescence technique (Horvath and Mason, 1978 Roy et at, 1980 Ridley and Schiff, 1981 Ridley and Hastie, 1981) horizontal lines represent measurements by infrared optical techniques (Drummond and Jarnot, 1978 Roscoe etal., 1981 Loewenstein etal., 1978a,b). Center Nitrogen dioxide as observed by optical measurement techniques, day (d) and night (n) points indicate data from Murcray et al. (1974), Goldman et al. (1978), Blatherwick et at (1980) horizontal bars are from Drummond and Jarnot (1978) and Roscoe et al. (1981). The N205 profile was obtained by Toon et al. (1986) at sunrise. Right Nitric acid observed by in situ filter sampling (open points) (Lazrus and Gandrud, 1974) and by infrared spectroscopy and mass spectroscopy (solid points) (Fontanella et at, 1975 Harries et al., 1976 Evans et al., 1978 Arnold et al., 1980 Murcray et al. as quoted by Hudson, 1982 Fischer et at, 1985). The envelope gives the error range.

There are more techniques available on the market for the combustion exhaust composition measurement. For example, the Fourier transform infrared (FTIR) spectroscopy. Continuous emission monitoring system (CEMS) MultiGas 2030 provides real-time, simultaneous measurement of the concentrations of flue gas components ranging from water vapor, nitrogen oxides, sulfur oxides, ElCl, ammonia, H2SO4, and many other compounds. Many organic species can... 

Synthesis of mesoporous molecular sieves MCM-41 and MCM-48 was carried out under microwave and hydrothermal conditions. Molecular sieves prepared were characterized using X-ray powder diffraction, scanning electron microscopy, nitrogen adsorption isotherms and infrared spectroscopy to evaluate the properties of these materials. It was observed that mesoporous molecular sieves synthesized under microwave conditions exhibit higher activity in oxidation of adamantanone by hydrogen peroxide to the respective lactone (Baeyer-Villiger oxidation). 

Conversion of nitric oxide to nitrogen dioxide and reactions of nitrogen oxides with other smoke components as studied by Eourier Transform Infrared Spectroscopy 27A36. 

Mesoporous alumina samples have been synthesized using poly(ethylene oxide)-based nonionic surfactants. The effect that the addition of n-alkylamines to the synthesis gel has on the texture and thermal stability of mesoporous aluminas is studied. Textural and structural characterization using nitrogen adsorption, powder X-ray diffraction, a1 nuclear magnetic resonance and Fourier Transform infrared spectroscopy, as well as catalytic n-hexane hydroisomerization tests are performed. 

Infrared spectroscopy has assisted in the determination of the structure of certain complex inorganic molecules, uch as the metal carbonyls, inter-halogen compounds, boron hydrides, and nitrogen oxides. The practice used has been to compare the observed spectrum with the spectrum expected for an assumed model on the basis... 

Whereas the distribution profile of the radicals in the bulk cannot be determined, the distribution of the products of their reaction with oxygen can. In other words, the degree and distribution of oxidative degradation in the bulk can be determined by measuring the distribution of the hydroperoxides and of their decomposition products using infrared spectroscopy (FTIR) [43, 44]. In Figure 21.1 the oxidation products after NO (nitrogen monoxide) treatment for a new prosthesis are reported [41-42]. 

The concentrations of ammonia, nitric oxide, nitrous oxide and for verification nitrogen dioxide are measured by non-dispersive infrared spectroscopy. Oxygen is determined by use of a magnetic device. 

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