Fourier transform infrared catalyst system

The use of cylindrical internal reflectance cells for HP-IR was pioneered by Moser and further modified by others.This method involves the use of an optically transparent internal reflectance crystal (typically ZnS, ZnSe, sapphire). Due to the inherently short path length, the method is not as sensitive as transmission-based IR, and a Fourier transform infrared (FTIR) spectrometer is therefore generally required. In addition, the type of crystal may need to be changed depending on the reaction of interest, as the optics may be corroded by some reagents or catalysts. However, as the path length is fixed regardless of conditions, it is much easier to quantify catalyst species, and unlike transmission systems the cells can also be used for the study of liquid-solid and gas-liquid-solid mixtures. ... 

PAH has been studied in detail for its role in silicification under ambient conditions and at neutral pH. It was demonstrated that PAH can facilitate the formation of nanometer and micrometer-size spherical silica particles imder mild conditions from an aqueous solution of a silica precursor (Fig. 6). It was shown by energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) that the PAH was incorporated into the final silica structures. In the absence of PAH the reaction mixture gelled in 1 day. These results indicate that PAH may act as a catalyst as well as a template or structure-directing agent in silicification. In this context, the behavior of this system is consistent with how Tacke described the role(s) of macromolecules that facilitate silica formation via scaffolding (see section II). 

Un-OH can also be copolymetized with propene on a MAO-pretreated glass surface by Et(Ind)2ZrCl2. Parts of the resulting copolymer are chemically bonded to the surface, as shown by extraction experiments, scanning electron microscopy (SEM) microscopy as well as Fourier transformation infrared spectroscopy (FUR) analysis. Similar results were reported for the copolymerization of ethene with Un-OH by the same catalyst system on the organically modified silicate montmorillonite (OMMT) resulting in PE-Un-OH/OMMT nanocomposites which consist of well-exfoliated OMMT dispersions and controlled degrees of PE functionalization. ... 

Accordingly, transient kinetic techniques which are able to provide unique information on the actual state of a working catalyst within a very short period of time [13,14] were applied to this complex and unstable catalytic system. Non-steady-state and steady-state isotopic transient kinetics (NSSTK and SSITK) combined with in situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFT) and temporal analysis of product (TAP) were performed in order to analyse some of the above mentioned key steps of the aromatisation process. 

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