Oxygen Atoms Of CO Research Articles

Real Time Observation of Decomposition of Methanol on Ru(001)-p(2 × 2)-O by a Temperature Programmed ESDIAD/TOF System

Abstract For the purpose of utilizing ESDIAD (Electron Stimulated Desorption Ion Angular Distribution) as a real time probe for surface chemical processes, we have developed a new instrument which can measure ESDIAD images and time of flight (TOF) spectra of desorbed ions in temperature programmed surface processes. TOF measurements are carried out to identify the mass of desorbed ions and to determine their kinetic energy distribution. This temperature-programmed (TP)-ESDIAD/TOF system was used to observe the decomposition processes of methanol on Ru(001)-p(2 × 2)-O. A halo pattern from the methyl group of methoxy species was observed at 100-200 K by the use of CH3OD, followed by a broad pattern from the methyl group at 230-250 K, and by a near-center pattern from the oxygen atom of CO above 300 K.

Catalytic addition of CH bonds to multiple bonds

Abstract

In‐situ Positron Emission of CO Oxidation

AbstractUsing a Neuro ECAT positron tomograph the Positron Emission computed Tomography (PET) has been utilized to image the catalytic oxidation of CO by using CO and CO2, labelled with short lived positron emitting nuclides. Studies were performed over highly dispersed ceria/γ‐alumina supported platinum and rhodium catalysts. With a mathematical model of the reaction kinetics, based on the elementary steps of the catalytic reaction and partially on literature surface science data, the effect of CeO2 promotion and the presence of NO were quantified in terms of the number of adsorption sites and adsorption equilibrium constants. Oxygen atoms of CO2 remain much longer in the catalyst bed than the carbon atoms, which is due to carbonate formation at the ceria surface and exchange of the oxygen atoms of these carbonate groups with the ceria lattice oxygen atoms. The heat of desorption of CO from the noble metal surface at low temperatures was found to be increased due to the presence of NO molecules at the surface. At higher temperatures NO dissociates, the adsorbed N and O atoms have a repulsive interaction with adsorbed CO molecules.

Fourier transform microwave spectroscopy of Hg–CO2

Pure rotational spectra of the mercury–carbon dioxide complex have been observed by a Balle–Flygare-type Fourier-transform microwave spectrometer with a high temperature pulsed valve. From the nuclear spin statistics associated with the oxygen atoms of CO2, the complex has been found to be T-shaped with C2v symmetry, as in the analogous rare gas–carbon dioxide complexes. The rotational constants, B and C, and the harmonic force constants for the van der Waals (vdW) modes have been determined from a nonlinear least-squares fit of the transition frequencies. The mercury–carbon distance has been derived to be 3.695 Å from the determined rotational constants. The permanent dipole moment of the complex has been determined to be 0.107 (3) from Stark effect measurement, where the value in parentheses is twice the standard deviation.

Utilization of CO 2 in the oxidative coupling reaction of methane over CaO based catalysts

Reactions by CH 4/CO 2/O 2 (100/100/1) gave higher C 2-compounds and ethene) yield than that by CH 4/O 2 (100/1) over CaO and BaOCaO catalysts at 1073 K. C 2-yield by CH 4CO 2O 2 reaction is even higher than the maximum theoretical yield by CH 4O 2 reaction, which suggests that one of the oxygen atoms of CO 2 is used for the hydrogen abstraction from methane. CO 2 is turned to CO. The reaction mechanism is proposed and the reactivity of the catalyst is discussed with relation to the catalyst properties.

Carbonate apatites from aqueous and non-aqueous media studied by ESR, IR, and X-ray diffraction: effect of NH4+ ions on crystallographic parameters.

Carbonate-containing apatites prepared from aqueous and non-aqueous media were investigated by ESR, IR, and X-ray diffraction. A typical asymmetric signal at g = 2.0, which many workers have observed in irradiated calcified tissues, is interpreted in terms of CO3(3)- and Co-2 and the trapped electron center, The CO3(3)- and CO2- ions originated from the carbonate which substitutes for the phosphate ion in the apatite crystalline structure. From the comparison of the data between the carbonate apatites prepared under the presence of Na+ and NH4+ ions, it is suggested that NH4+ ions contribute to the crystallographic parameters, either by substituting in the structure or by suppressing the CO3 incorporation into the structure, or by both. The production of the CO2- radical ion could be accounted for based on the concept of hydrogen bond between the oxygen atom of CO2(3)- and the hydrogen atom of NH4+.

Preparation and characterization of tetrakis (β-ketophosphonato) thorium(IV) complexes

Tetrakis (β-ketosphonato) thorium(IV) complexes have been prepared using a liquid—liquid extraction method. They have been well characterized by i.r., Raman, 1H, 13C and 31P NMR spectroscopies. β-ketophosphonates act as anionic chelating ligands and are coordinated by the PO and CO oxygen atoms. An asymmetric repartition of the negative charge on the chelate ring is observed. A stabilities order of the studied β-ketophosphonato-thorium complexes has been established.

Basicity of transition metal carbonyl complexes : IX. An infrared study of lewis acid reactions with cyclopentadienyl and arene derivatives of groups VI and VII transition metal carbonyls and nitrosyls

The different courses of the interactions of cyclopentadienyl and arene derivatives of Group VI and VII transition metal carbonyl and transition complexes with Lewis acids, in solutions, have been studied by IR spectroscopy. The information of adducts involving the metal atom was observed for CpRe(CO) 2L (L = CO, PR 3) with SnCl 4, SnBr 4, TiCl 4; AreneM(CO) 3 (M = Cr, Mo, W) with SnCl 4, TiCl 4; and Ph 3PC 5H 4M(CO) 3 (M = Cr, Mo, W) with TiCl 4 and AlCl 3. Complexes CpM(CO) 2NO and CpM(CO(NO)PPh 3, depending on thier donor and acceptor nature, form adducts involving the oxygen atoms of CO or NO groups or the metal atom. CpCr(NO) 2Cl reacts with Lewis acids via the chlorine atom. The relative basicity of the different sites in the complexes investigated is discussed.