Raman alcohols

S. Hatem and S. Valladas-Dubois. Bull. soc. chim. France 1949, 604-7. UV, Raman alcohol-cyclic amines, pyridine, />-toluidine. 

The varying actual orientation of molecules adsorbed at an aqueous solution-CCU interface with decreasing A has been followed by resonance Raman spectroscopy using polarized light [130]. The effect of pressure has been studied for fatty alcohols at the water-hexane [131] and water-paraffin oil [132] interfaces. 

The behavior of insoluble monolayers at the hydrocarbon-water interface has been studied to some extent. In general, a values for straight-chain acids and alcohols are greater at a given film pressure than if spread at the water-air interface. This is perhaps to be expected since the nonpolar phase should tend to reduce the cohesion between the hydrocarbon tails. See Ref. 91 for early reviews. Takenaka [92] has reported polarized resonance Raman spectra for an azo dye monolayer at the CCl4-water interface some conclusions as to orientation were possible. A mean-held theory based on Lennard-Jones potentials has been used to model an amphiphile at an oil-water interface one conclusion was that the depth of the interfacial region can be relatively large [93]. 

ALCOHOLS,HIGHERALIPHATIC - SURVEY AND NATURALALCOHOLSMANUFACTURE] (Voll) -analysis using Raman spectroscopy [SPECTROSCOPY, OPTICAL] (Vol 22)... 

Iron(II) complexes are often included in studies when complexes are prepared from a large number of different metal ions. 2-formylpyridine thiosemicarbazone, 5, forms brown [Fe(5)2A2] (A = Cl, Br) when prepared in ethanol and [Fe(5-H)2] from aqueous alcohol solution [156], All of these complexes are diamagnetic. The resonance Raman and infrared spectra of [Fe(5-H)2] were examined in detail [130] and coordination occurs via the pyridyl nitrogen, azomethine nitrogen and thiol sulfur. There is appreciable d-d sulfur-to-iron(II) Jt-bonding. Solution studies of iron(II) complexes of some 5-substituted-2-formylpyridine thiosemicarbazones have been reported [157], but no solids... 

In condensed phases, the noncoincidence effect between IR and Raman spectra provides insights into the intermolecular coupling [170, 171]. The combination of IR and Raman spectroscopy is also useful in the study of alcohol clusters in the supercritical state [25]. 

The simplest unsaturated alcohol with ip3-carbon O—H is allyl alcohol (propenol). The monomer occurs in two energetically similar conformations in the gas phase [145, 240], which are both stabilized by intramolecular O—H- -n interactions. The dimer has only been studied in matrix isolation [241]. Spectroscopic evidence for an intermolecular O—H ji hydrogen bond was found. A vibrational (IR and Raman) supersonic jet measurement would be able to unravel the different monomer and dimer conformations involved. 

W. Richter and D. Schiel, Raman spectrometric investigation of the molecular structure of alcohols Conformational dynamics of ethanol. Ber. Bunsenges. Phys. Chem. 85, 548 552... 

M. Paolantoni, P. Sassi, A. Morresi, and R. S. Cataliotti, Raman noncoincidence effect on OH stretching profiles in liquid alcohols. J. Raman Spectr. 37, 528 537 (2006). 

Nakamoto K. Complexes of alkoxides, alcohols, ethers, ketones, aldehydes, esters and carboxylic groups, in Infrared and Raman spectra of inorganic and coordination compounds, Wiley, 2009, 62-67. 

Many of the characterization techniques described in this chapter require ambient or vacuum conditions, which may or may not be translatable to operational conditions. In situ or in opemndo characterization avoids such issues and can provide insight and information under more realistic conditions. Such approaches are becoming more common in X-ray adsorption spectroscopy (XAS) methods ofXANES and EXAFS, in NMR and in transmission electron microscopy where environmental instruments and cells are becoming common. In situ MAS NMR has been used to characterize reaction intermediates, organic deposits, surface complexes and the nature of transition state and reaction pathways. The formation of alkoxy species on zeolites upon adsorption of olefins or alcohols have been observed by C in situ and ex situ NMR [253]. Sensitivity enhancement techniques play an important role in the progress of this area. In operando infrared and RAMAN is becoming more widely used. In situ RAMAN spectroscopy has been used to online monitor synthesis of zeolites in pressurized reactors [254]. Such techniques will become commonplace. 

A. Picard, I. Daniel, G. Montagnac and P. Oger, In situ monitoring by quantitative Raman spectroscopy of alcoholic fermentation by Saccharomyces cerevisiae under high pressure, Extremophiles, 11, 445 52 (2007). 

There are some reports of kinetic investigations of Ru-catalysed oxidations in which the nature of the active catalyst or catalyst precursor is unclear but which may be predominantly [RuO ] . Two papers used electronic or Raman spectroscopy to identify such species [212], [222]. Examples in which [RuO ]" has been shown to be the active species or catalyst precursor in the oxidation of secondary alcohols to ketones include... 

Temperature programmed reaction (TPR) experiments were carried out by adsorbing allyl alcohol and allyl iodide on a 9.0 wt% Mo03/Si02 sample and monitoring the evolved products by mass spectrometry. The Raman spectra of the pure liquid reference compounds are shown in Fig. 2. They agree well with those reported earlier (18-20). 

In order to circumvent this problem the rate-determining step was bypassed by using more reactive reagents, allyl alcohol and allyl iodide. These allylic probes were expected to adsorb on the molybdenum oxide surface to provide, respectively, M-O-C and M-C bonded intermediates. These studies were carried out with a sample of 9.0 wt% Mo03/Si02, which Raman spectroscopy and x-ray diffraction showed to consist of fine (- 5nm) crystallites of M0O3 (23). 

Unfortunately, there are no bands that can be clearly identified with M-C or M-O-C vibrations. These modes may be difficult to observe by Raman spectroscopy because the bonds are only we y polarized. In addition it is believed that the vibrations of light atoms bonded to a metal center are broadened by coupling to die support (24). Nevertheless, the differences in the spectra of the two species suggest that the proposed stractures are formed. For the case of allyl alcohol, isotopic substitution experiments on supported... 

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