Infrared absorption of gaseous benzoyl radical C6H5CO recorded with a step-scan Fourier-transform spectrometer

First multi-tool exploration of a gas-condensate-pyrolysate system from the environment of burning coal mine heaps: An in situ FTIR and laboratory GC and PXRD study based on Upper Silesian materials

A methodological approach to the complex geochemical analysis of the coal fire in burning coal mine heaps (BCMH) of Upper Silesian Coal Basin has been developed. The other approach used is gas chromatography and indicatory tubes. Powder X-Ray Diffraction is applied for phase analysis to determine the species composition of mineral condensates present within and around gas flues. The gas compositions are proved to be extremely variable, when comparing both different BCMH and flues or flue zones of the same heaps. One outstanding determination concerns GeCl₄, found in most samples often in large quantities. No evident dependence between the gas and mineral condensate compositions is found: N-rich condensates may but do not have to be associated with NH₃-, pyridine-, or NO_x-rich gases. This is also true for S-rich and Cl-rich mineralization in connection with gases of SO₂, H₂S, OCS, CS₂, thiophene, dimethyl sulfide, dimethyl disulfide, HCl, and various halogenated hydrocarbons. Fluorine is rarely present as HF, whereas SiF₄ occurs more frequently and in much larger quantities. AsH₃ is mainly a trace gas but may locally be enriched. Besides the common gases, a number of trace gases is also determined based on residual FTIR spectra. Those with the highest presence chance include cyanogen isocyanate, cyanogen N-oxide, (iso)cyanic acid, c-cyanomethanimine (ethylenediimine), isocyanatomethane, iodocyanoacetylene, acetonitrile, acetaldehyde, m-hydroxybenzonitrile (m-cyanophenol), isonitrosyl chloride, nitrosyl isocyanide, difluorosilane, pentacene, triphenylene, thiazolidine, cyclohexane, and a trinitrenetriazine. The occurrence of some metals and semimetals (e.g., Al, Mg, Ga) as neutral hydroxides, suggested by other authors to occur in natural gases, is possibly confirmed. The presence of trace metal carbonyls, nitrosyls and hydrides is also possible.

Structure and Electronic Transitions of C7H4O2+ and C7H5O2+ Ions: Neon Matrix and Theoretical Studies

C₇H₄O₂⁺ and C₇H₅O₂⁺ ions and the respective neutrals have been investigated by absorption spectroscopy in neon matrixes following mass selection of ions produced from salicylic acid. Three electronic transitions starting at 649.6, 431.0, and 372.0 nm are detected for C₇H₄O₂⁺ and assigned on the basis of CASPT2 energies and Franck-Condon simulations as the excitations from the X ²A″ to the 1 ²A″, 2 ²A″, and 3 ²A″ electronic states of 6-(oxomethylene)-2,4-cyclohexadien-1-one ion (A⁺). Absorptions commencing at 366.4 nm are observed for C₇H₅O₂⁺ and assigned to the 1 ²A' ← X ²A' electronic transition of (2-hydroxyphenyl)methanone ion (J⁺). Neutralization of J⁺ leads to the appearance of four absorption systems attributed to the 4 ²A″, 3 ²A″, 2 ²A″, and 1 ²A″ ← X ²A″ transitions of J with origin bands 291.3, 361.2, 393.8, and 461.2 nm.

Direct aerobic liquid phase epoxidation of propylene catalyzed by Mn(iii) porphyrin under mild conditions: evidence for the existence of both peroxide and Mn(iv)-oxo species from in situ characterizations

Manganese(iii) porphyrin exhibited excellent activity for the selective oxidation of propylene. Experimental evidences that the generation of peroxide and Mn(iv) oxo species, which was well confirmed by in situ IR, in situ UV and MS.