In Situ FT-IR Analysis

To trace the surface-adsorbed species during the transient NO reduction, in situ FT-IR analysis was applied. Analyzing the transient change of these adsorbates would help in understanding the SCR mechanism and identifying the rate-determining step. 

---

Upon the in-situ FT-IR analysis of KNiCa/ZSl catalyst, no C-H bands were detected in the region of 2700 - 3100 cm corresponding to CHx adsorbed species after the reaction and CH4 introduction at 700°C into in-situ cell. The adsorbed species formed upon CH4 adsorption was postulated mainly as a type of Ni-C. 

A dynamic method for acquiring and treating infrared spectroscopic data from the imidization of a number of polyimide systems is presented. In situ FT-IR analysis of polymer reactions is preferred when doing comparitive studies on a number of polymer systems. For systems where these reactions occur at relatively high temperatures, it is often difficult to obtain good isothermal data for determining kinetic parameters. Kinetic data for several polyimide systems are shown and compared. 

Lastiy, in situ FT-IR spectroscopy was performed. A specific cell that allows researchers to perform the irradiations and to record the infrared spectra without removing the sample (FT-IR analysis during the beam stops) was placed on the medium energy line facility of the GANIL accelerator. Thus, modifications of SHI-irradiated polyethylene could be studied in situ. 

In such a chemistry, the reactivity demonstrated in the previous paragraphs attributes the following roles to the three main SCR reactants (1) NO2 forms surface nitrates and nitrites via a disproportionation route (2) NO reduces the nitrates to nitrites (3) NH3 decomposes/reduces the nitrites to N2. The related basic reaction steps, originally identified by transient reaction analysis and recently confirmed also by in situ FT-IR [10] over Fe-ZSM-5, are summarized in Table 9.1. 

The reaction investigation of ammonia synthesis on iron catalj ts by laser Raman and in situ FT-IR spectroscopy showed that the main chemisorbed species were molecular state N2(ad) rather than atomic one N (ad). The analysis with AES by Spencer et al. showed that N (ad) was of very high coverage on... 

Elsenheimer DW, Valley JW (1992) In situ oxygen isotope analysis of feldspar and quartz by Nd YAG laser microprobe. Chem Geol Isotope Geosci Section 101 21-42 Elsenheimer DW, Valley JW (1993) Submillimeter scale zonation of in quartz and feldspar, Isle of Skye, Scotland. Geochim Cosmochim Acta 57 3669-3676 Esler MB, Griffith DWT, Wilson SR, Steele LP (2000) Precision trace gas analysis by FT-IR spectroscopy. 

In any case, a detrimental effect has also been reported after the addition of the external modified particles a decrease in the formation of silica network (Si—O—Si) in the coating matrix, as observed in Fourier transformed infrared (FT-IR) analysis [42]. This effect hinders the final improvement in the scratch resistance that the particles could produce the first critical load of 1.8 N is obtained after adding a significant amount of particles (Iwt %) that is close to 1.9N for the unreinforced coating. Tower particle addition has a detrimental effect on the scratch resistance, giving even lower values of critical load ( 0.9N). Meanwhile, the in situ formed silica particles produce a clear improvement in the first critical load, with a reported value of 4N. 

Yeom and Frei [96] showed that irradiation at 266 nm of TS-1 loaded with CO and CH3OH gas at 173 K gave methyl formate as the main product. The photoreaction was monitored in situ by FT-IR spectroscopy and was attributed to reduction of CO at LMCT-excited framework Ti centers (see Sect. 3.2) under concurrent oxidation of methanol. Infrared product analysis based on experiments with isotopically labeled molecules revealed that carbon monoxide is incorporated into the ester as a carbonyl moiety. The authors proposed that CO is photoreduced by transient Ti + to HCO radical in the primary redox step. This finding opens up the possibility for synthetic chemistry of carbon monoxide in transition metal materials by photoactivation of framework metal centers. 

Budevska, B.O., Sum, S.T. and Jones, T.J. (2003) Application of mulfivariate curve resolution for analysis of FT-IR microspectroscopic images of in situ plant tissue. Appl. Spectrosc., 57, 2. 

Wetzel, D.L. and LeVine, S.M. (1998) Fourier transform infrared (FT-IR) microspectroscopy a new molecular dimension for tissue or cellular imaging dimension for tissue or cellular imaging and in situ chemical analysis. Cell. Mol Biol, 44 (1), 1-280. 

Spectroscopy. FT-IR spectra were recorded on a Nicolet F-730 spectrometer equipped with an in-situ flow-cell. Electron Paramagnetic Resonance (EPR) spectra were recorded in X-band with a Bruker ESP-300 with a fE (,4 cavity. Diffuse Reflectance Spectroscopy (DRS) spectra were recorded on a Cary-5 spectrofotometer with a BaS04 integration-sphere in the UV-VIS-NIR. Molecular graphics analysis was done with Hyperchem 3.0 for Windows (Hypercube Inc.). 

Keywords Hydroialciie-likc compounds Hydroxylation of Phenol Selective oxidation Structure-activity relationships In situ powder X-ray diffraction In situ DRIFT FT-IR spectroscopy Thermal analysis (TGA-DTA-EGA-TPRO) Synthesis methodology Influence of reaction parameters Ordered network Synergism... 

In Situ Analysis in a Furnace Successful in situ measurement of coal pyrolysis have recently been made (24, 25)> In one application (24), small samples of coal were rapidly injected into a preheated zone which is traversed by the IR beam With this apparatus spectra have been obtained for gases at temperatures up to lOOO C In the second application a gas stream of predetermined composition is heated during transit through a bed of alumina chips maintained at furnace temperature The gas stream then enters a test section, maintained at the same temperature, where coal is introduced through a water cooled injector. After a variable residence time the reacting stream crosses the FT-IR beam and is quenched in a water cooled collector FT-IR spectra have been obtained at temperatures up to 1200 0 The input gas stream and effluent stream can also be analyzed by routing the stream through an infrared cell The spectra presented in Fig 22 were of the effluent gas in the external cell ... 

We have investigated the photooxidation of toluene in several different zeolite hosts (BaX, BaY, CaY, BaZSM-5, and NaZSM-5) using in-situ Fourier Transform Infrared (FT-IR) spectroscopy and ex-situ Gas Chromatography (GC) to analyze product formation and product yields. This combined approach allows for a more detailed analysis of the product distribution. The product selectivity in these reactions appears to be governed by the presence of a small number of acid sites rather than by the framework composition or topology of the zeolite host. 

---