Aromatics-oxygen complex

Methyl benzoate, anisole, and diphenyl ether each give sandwich compounds with chromium vapor, although in rather low yield (32, 55, 110). Chromium appears to attack alkyl ethers and this deoxygenation probably competes with complexation with the aromatic oxygen compounds. No simple product has been isolated from chromium atoms and aniline, but bis(7V,7V-dimethylaniline)chromium has been prepared (32). The behavior of molybdenum and tungsten vapors closely resembles that of chromium in reactions with oxygen- and nitrogen-substituted arenes (113). 

DRIFT spectra of a partially converted CuCI/soot mixture (50% convmion), and a FeOCl/soot mixture (60% conversion) are depicted in figure 4. Tte spectrum of soot after an identical heat treatment is shown for comparison. The DRIFT spectra contain three main absorptions located at 1738 cm, 1607 cm and centered around 1257 cm. The 1607 cm absorption is caused by aromatic stretching vibrations of the soot, which are enhanced by polar functional groups like quinone [20], The other two absorptions have been assigned to oxygen complexes formed on the soot surface lactones (1738 cm" ) and ether-like complexes (1257... 

Many fluorescence sensors are based, not on direct fluorescence, but on the quenching of fluorescence. Molecular oxygen, for example, is one of the best col-lisional quenchers. Oxygen can quench the fluorescence from polycyclic aromatic hydrocarbons complexes of ruthenium, osmium, iridium, and platinum and a number of surface-adsorbed heterocyclic molecules. An oxygen sensor can be made by immobilizing the fluorophore in a thin layer of silicone on the end of a fiber-optic bundle. Sensors for SO-, haliilcs, H-O-, and several other molecules have been ba.sed on fluorescence quenching. 

Pyrolysis oil consists of a complex mixture of aliphatic and aromatic oxygenates and particulates. Also known as cmde bio-oil, it is very viscous, acidic and unstable liquid with relatively low-energy density compared to conventional fossil oil. This nature of the bio-oil requires costly posttreatment processes that make the commercial pyrolysis economically less... 

In liquids of aliphatic and aromatic amines and even HA(L)S including N-methylated HA(L)S, saturated with oxygen, the appearance of additional absorption bands was already observed which confirms the assumption that HA(L) S-oxygen complexes play an important role as intermediates. Aspects of the outlined mechanisms can be combined into a general scheme as shown in Scheme 8. 

The organic chemical structural types believed to be characteristic of coals include complex polycyclic aromatic ring systems with connecting bridges and varied oxygen-, sulfur-, and nitrogen-containing functionalities. 

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