Oxygen compounds spectroscopy

Regarding ozonation processes, the treatment with ozone leads to halogen-free oxygenated compounds (except when bromide is present), mostly aldehydes, carboxylic acids, ketoacids, ketones, etc. [189]. The evolution of analytical techniques and their combined use have allowed some researchers to identify new ozone by-products. This is the case of the work of Richardson et al. [189,190] who combined mass spectrometry and infrared spectroscopy together with derivatization methods. These authors found numerous aldehydes, ketones, dicarbonyl compounds, carboxylic acids, aldo and keto acids, and nitriles from the ozonation of Mississippi River water with 2.7-3 mg L 1 of TOC and pH about 7.5. They also identified by-products from ozonated-chlorinated (with chlorine and chloramine) water. In these cases, they found haloalkanes, haloalkenes, halo aldehydes, haloketones, haloacids, brominated compounds due to the presence of bromide ion, etc. They observed a lower formation of halocompounds formed after ozone-chlorine or chloramine oxidations than after single chlorination or chlorami-nation, showing the beneficial effect of preozonation. 

It is well known for example in the saturated LDPE polymer chains that a certain number of double bounds exist which can be measured with IR spectroscopy. By extraction with non-polar solvents and GC separation, numerous alkanes and alkenes can be identified which are dissolved in small concentrations in the PE. The odor thresholds of these compounds are in general so high that these hydrocarbons play no sensory role. As a result no correlation can be made between the total amount of volatile compounds isolated from PE or the fingerprint chromatogram from a GC separation and the sensory properties of a sample. The relevant sensory compounds as a rule are the (order of magnitude) less concentrated oxygenated compounds in the... 

Se NMR SPECTROSCOPY AND ITS APPLICATIONS IN CHEMISTRY 125 Table 3. Se chemical shifts in various sclcniiim( IV) oxygen compounds... 

Rhodium and ruthenium complexes of 2,2 -bis(diphenylphosphino)-l,l -binaphthyl (BINAP) have frequently been used as catalysts for enantioselective hydrogenation of olefins and ketones." "" From consideration of the literature on this subject, it was proposed that the presence of a mono-oxidized BINAP in an organometallic catalyst could have interesting consequences." Accordingly, Rh(BINAP)(CO)Cl was prepared, and upon reaction with O2, (BINAP(0))Rh(CO)Cl was formed. These compounds were authenticated by X-ray crystallography, and IR and NMR spectroscopies. The kinetics of this reaction were monitored by solution (chloroform was the solvent) IR spectroscopy. In the absence of added CO, the oxygenated compound was formed in about 50% yield. BINAP(0)2 and CO2 are also produced. Plots of obs (from loss of reactant) versus [O2] at various temperatures yielded... 

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