Reaction Product Of CO Research Articles

Quantification of the influence of NO2, NO and CO gases on the determination of formaldehyde and acetaldehyde using the DNPH method as applied to polluted environments

Airborne aldehydes have a significant impact on human health, especially in confined spaces such as tunnels, vehicle depots, industrial and construction sites where combustion devices are in operation. The standard method for the measurement of aldehydes (formaldehyde and acetaldehyde) uses the 2,4-dinitrophenylhydrazine (DNPH) derivatisation method. However this method has been reported to be prone to interference from ozone and NO2. The interference from these compounds have been viewed as chromatographic interferences on the quantification of formaldehyde. However, in these polluted environments, elevated levels of NO2 along with NO and CO are normally present. This study quantifies the impact these gases have on the quantification of formaldehyde and acetaldehyde, by evaluating the chromatographic interferences, consumption of the DNPH during sampling, and the effect these gases have on the capture and retention of the aldehydes on the DNPH cartridge during sampling. For the first time, CO was shown to react with DNPH and interfere with the determination of acetone. The reaction product of CO with DNPH was determined to be a compound that could be mistaken for acetone-DNPH. It has been found that the presence of NO, NO2 and CO in the sampled air consumes the DNPH cartridges, which results in the loss of formaldehyde and acetaldehyde during long-term sampling, and therefore extra capacity of DNPH is required for the measurement of formaldehyde and acetaldehyde in polluted environments. These findings reveal a potential risk of underestimation of formaldehyde and acetaldehyde measurements in a polluted workspaces such as a diesel engine operated environment where NOx and CO concentration levels could be high.

CO Capture and Conversion to HOCO Radical by Ionized Water Clusters

The CO molecule can interact with the hydroxyl radical ((•)OH) via either a weak noncovalent interaction or strong covalent bonding. Upon the ionization of neutral water clusters, the resulting water cluster cations produce protonated water clusters and hydroxyl radicals. In this regard, we investigate the interactions of a CO molecule with water dimer and trimer cations using density functional theory (DFT), Möller-Plesset second-order perturbation theory (MP2), and coupled cluster theory with single, double, and perturbative triple excitations [CCSD(T)]. It is found that the reaction products of CO by the water dimer and trimer cations form a HOĊO radical solvated by a protonated water monomer and dimer, respectively. These radicals are useful intermediates to make oxalic acids, formic acids, metal ligands, and so on, which is important in green chemistry.

Gas-phase photodissociation of CH3COCN at 308 nm by time-resolved Fourier-transform infrared emission spectroscopy

By using time-resolved Fourier-transform infrared emission spectroscopy, the fragments of HCN(v = 1, 2) and CO(v = 1-3) are detected in one-photon dissociation of acetyl cyanide (CH(3)COCN) at 308 nm. The S(1)(A(")), (1)(n(O), π(∗) (CO)) state at 308 nm has a radiative lifetime of 0.46 ± 0.01 μs, long enough to allow for Ar collisions that induce internal conversion and enhance the fragment yields. The rate constant of Ar collision-induced internal conversion is estimated to be (1-7) × 10(-12) cm(3) molecule(-1) s(-1). The measurements of O(2) dependence exclude the production possibility of these fragments via intersystem crossing. The high-resolution spectra of HCN and CO are analyzed to determine the ro-vibrational energy deposition of 81 ± 7 and 32 ± 3 kJ∕mol, respectively. With the aid of ab initio calculations, a two-body dissociation on the energetic ground state is favored leading to HCN + CH(2)CO, in which the CH(2)CO moiety may further undergo secondary dissociation to release CO. The production of CO(2) in the reaction with O(2) confirms existence of CH(2) and a secondary reaction product of CO. The HNC fragment is identified but cannot be assigned, as restricted to a poor signal-to-noise ratio. Because of insufficient excitation energy at 308 nm, the CN and CH(3) fragments that dominate the dissociation products at 193 nm are not detected.

The 11C-radioisotopic study of methanol conversion on V-MCM-41: The influence of methyl iodide on the transformation

The methanol conversion and a feasible methanol co-reaction with methyl iodide were studied on a vanadium incorporated MCM-41 type (V-MCM-41) mesoporous catalyst, which was prepared by a direct hydrothermal synthesis method. Adsorption/desorption as well as conversion derivates of radioactive methanol were easily followed by radioactivity detectors on V-MCM-41. The transformation and co-reaction products were analyzed by a gas chromatograph equipped with Radio/FID detectors. The radiodetector was applied to distinguish 11C-derivates from the non-radioactive methyl iodide and its derivates. The radio-labeling method proved methanol transformation to methylal and, in the presence of methyl iodide, decided the roles of methyl group and iodide of methyl iodide in newly synthesized methyl iodide formation in the absence of oxygen gas.

The reaction of carbon monoxide with palladium supported on cerium oxide thin films

In this study we probe the reaction of carbon monoxide with Pd nanoparticles supported on cerium oxide thin films. With the use of soft X-ray photoelectron spectroscopy (sXPS), and temperature programmed desorption (TPD) the surface intermediates and pathways leading to reaction products of CO on Pd supported on ceria were investigated. When Pd is supported on the stoichiometric CeO 2 surface (Ce +4) only the molecular adsorption of CO on Pd is visible (286.4 eV). All of the CO desorbs below 520 K, however a small amount of O exchange between the CO and the ceria was indicated through the acquisition of labeled 18O from the substrate in the desorbed CO. The Pd nanoparticles are activated on partially reduced CeO x to promote the dissociation of <10% of the CO as indicated by a C–Pd species (284.4 eV) in sXPS. The C recombines with O from the ceria and desorbs between 600 and 700 K. The majority of the CO does not dissociate, however, and the degree of dissociation does not increase with the degree of ceria reduction. This result is in contrast with Rh nanoparticles supported on ceria where the degree of dissociation increased with the degree of ceria reduction and nearly total dissociation was obtained when the ceria was highly reduced.

Carbonic anhydrase in the gastrointestinal mucus of mammals—possible protective role against carbon dioxide

We show here that luminal mucus from the colon and the stomach of guinea pigs, mice and humans exhibits substantial carbonic anhydrase (CA) activity, by which the velocity of the CO 2 hydration reaction is accelerated 1000–2000-fold, approximately 1/10 of what is found in the red cell. Although this CA shares several properties with CA II, studies with CA II-deficient mice show that gastrointestinal mucus CA is not affected in these animals and thus does not appear to be CA II. We speculate that the mucus layer covering the luminal surface of gastrointestinal epithelium can, due to the presence of CA, maintain a normal tissue pCO 2 in the epithelium, even when the pCO 2 values in the lumen are much higher, as is known for stomach and colon. To test this hypothesis, we have developed a mathematical model which describes (a) diffusion of CO 2 and HCO 3 − across the mucus layer and (b) H + transport mediated by continuous secretion of mucus, which due to its high H + buffer capacity transports H + by convection towards the lumen. The model predicts that continuous transport of the reaction products of CO 2 towards the lumen, by diffusion and convection, protects the epithelium against high CO 2 partial pressures in the lumen.

Cure Behaviour and Structure of Dicyanate-Epoxy Novolac Blends

The cure characteristics of bisphenol A dicyanate-novolac epoxy resin blends were investigated by gel time determination and dynamic DSC. The effects of the proportion on the structures of cured blends were investigated by FTIR. In situ FTIR was utilized to study the curing mechanism and curing kinetics. The results indicated the distinct catalytic effects of the novolac epoxy resin on the curing of bisphenol A dicyanate. Due to considerable amounts of unepoxidized phenol present in the novolac epoxy resin, the reactions between phenol and cyanate disturbed the formation of the co-reaction products. The curing reactions of the blends indicated by in situ FTIR did not follow the Bauer mechanism totally. A composite mechanism of triazine-epoxy insertion and epoxy-cyanate reaction indwells in the systems. The authors suggest that most of the oxazolidinone present in the blends is formed by isomerization of oxazoline rather than by insertion of epoxy into isocyanurate. The amount of epoxy resin in the blend did not alter the curing mechanism, but had significant effects on the kinetic behaviour.

The Co + CO Reaction: Infrared Matrix Isolation Study and Density Functional Calculations

The Co + CO reaction argon has been reinvestigated using deposition of ground-state reagents in solid argon. The Co + CO reaction products observed without activation energy are Co2CO, a van der Waals Co···CO complex, and the higher carbonyl species Co(CO)x. Infrared radiation at approximately 3000 cm-1, to promote Co into the first excited-state b 4F (3d84s1 configuration), converts the van der Waals complex to the chemically bound, most stable carbonyl form CoCO. A second irradiation with an approximately 580 nm wavelength (17000 cm-1) reconverts the chemically bound CoCO (2Δ) state into the Co···CO van der Waals (4Φ) state. The photoprocess is fully reversible. Isotopic data on ν1, ν2, ν3, 2ν1, ν1 + ν2, and ν1 + ν3 have been measured in the near- and far-infrared regions for the carbonyl form. This enables a complete harmonic force-field calculation based on a linear geometry, in agreement with all theoretical predictions. DFT calculations of the geometrical and electronic properties of CoCO complexes from the Co + CO reaction are also presented and compared to the experimental values. Reaction mechanisms are proposed and comparisons with bond force constants of NiCO and CuCO are also presented.

The gaseous reaction of vinyl radical with oxygen

The gaseous reaction of vinyl radical with oxygen has been experimentally investigated. C2H3 radical was produced by laser photolysis of C2H3Br at 248 nm. The vibrationally excited products of the reaction were detected by time-resolved Fourier transform infrared emission spectroscopy. H2CO(ν1), HCO(ν1,ν3), and CO2(ν3) are ascertained as the main emitters. The most favorable product channel is HCO and H2CO. The reaction channel leading to CO2+CH3 has been found for the first time. The minor reactions leading to C2H2+HO2, C2H3O+O, and C2H2O2+H may also occur. A secondary reaction product of CO is observed, which is generated from the primary reaction product HCO. Combining theoretical analysis with the present experimental results, the reaction pathways are clarified. The results are of importance for understanding the combustion processes of hydrocarbon.

Preparation, Structure, and Thermal Decomposition of Co(II) Complexeswith 2,3- and 2,5-Dichlorobenzoic Acid and Imidazole

The reaction products of Co(II)-2,3- and -2,5-dichlorobenzoate with imidazole (1, 2; CoL 2⋯2imdċ2H2O, L=C7H3Cl2O , imd=imidazole) were characterized by their spectroscopic and thermochemical properties. The compounds crystallize in the monoclonic system with space group = P21/c, a=13.848(3), b=12.841(3) A, c= 7.064(2) A, β=98.12 °, V=1243.5(4) A3, Z=2 for 1 and space group =P21/n, a=13.293(3), b= 6.964(2), c=13.800(3) A, β=108.92(3) °, V=1208.6(4) A3, Z=2 for 2. The complexes lose their crystal water in one step at 333 K and subsequently decompose to CoO with intermediate formation of Co3O4.

Film thickness effects in the Co–Si1−xGex solid phase reaction

The thickness dependence of the reaction of cobalt with epitaxial silicon–germanium alloys (Si1−xGex) has been studied. The reaction products of Co with (100)-oriented Si0.79Ge0.21 after annealing at 800 °C depended on the thickness of the Co film. Complete conversion to CoSi2 occurred only when the thickness of the Co layer exceeded 350 Å. Interface reactions with Co layers thinner than 50 Å resulted in CoSi formation, while a mixture of CoSi and CoSi2 was formed at intermediate thicknesses. X-ray diffraction and extended x-ray absorption fine structure measurements indicated no measurable incorporation of Ge had occurred in either the CoSi or CoSi2. The threshold thickness for nucleation of CoSi2 on (100)-oriented Si1−xGex was determined in the range 0⩽x⩽0.25. The threshold thickness increased superlinearly with the Ge concentration x, and did not depend on the doping of the Si(100) substrate or the strain state of the Si1−xGex film. The observed thickness effect was attributed to preferential Co–Si bonding in the reaction zone and the energy cost of Ge segregation, which accompanies the formation of CoSi and CoSi2 during the reaction of Co with Si1−xGex.

Reaction products of CO with square-planar platinum(II)-( N, N-chelate) complexes: synthesis and reactivity

Carbon monoxide adds to [PtCl(R)(N-N)] (R=hydrocarbyl group; N-N = chelating N, N-ligand) to afford neutral five-coordinate [PtCl(R)(CO)(N-N)] or cationic four-coordinate [Pt(R)(CO)(N-N)] + complexes, depending on the the sterical crowding of the N, N-ligand. For R-aryl, a migratory insertion process follows under mild conditions and the corresponding acyl species are obtained. Some reactions of the five-coordinate adducts with nucleophiles are reported, and a substitution at the metal or an addition to the coordinated carbon monoxide are described.

Crystal and molecular structure of a cobalt(II) complex with bis(benzimidazol-2-ylmethyl)-methylamine (L)

The reaction product of Co(II) chloride and the title ligand L, formulated as CoLCl2·CH3OH, was prepared and characterized by means of structural and spectroscopic measurements. The violet crystals are orthorhombic, (space groupP212121) witha=8.093(2),b=14.883(3),c=16.831(3) A, andZ=4. The structure consists of discrete molecules with pseudo-, noncrystallographic twofold symmetry in which the Co atom is coordinated in trigonal bipyramidal geometry by three nitrogen and two chlorine atoms. The ligand L is coordinated to the Co atom in afac mode and two chlorine atoms are incis-positions. The structure was confirmed by IR-spectra.

Reactivity of carbon dioxide at nickel (110)

Adsorption and reactivity of carbon dioxide at the clean and oxygen precovered Ni(110) surface has been studied by means of EELS and LEED. On the clean surface two different types of CO 2 molecules have been observed by EELS at 135 K, one being the undisturbed linear configuration. With increasing temperature the linear molecule changes into a different species which precedes dissociation at 220 K into CO and O. EELS and LEED data of the intermediate species support the assumption that it is a bent CO − 2 anion adsorbed in C 2v symmetry with twofold oxygen coordination to the surface. Oxygen preadsorption stabilizes the linear CO 2 molecule up to higher temperatures which does not convert into a bent species in this case. Instead, a reaction product of CO 2 and O is found and interpreted as a carbonate species.

Electron removal during the D.C. discharge afterglow of carbon monoxide

Microwave diagnostics indicates that electron-ion two-body recombinations occurs with α r = = 6.8 ± 1.2 × 10 -7 cm 3/sec. For p ⩾ 2 Torr the removal rate increases with pressure indicating attachment to some reaction product of CO.

Phenolic–nitrile rubber copolymers

Nitrile rubbers have often been used together with phenolic resins in molding materials to produce an impactresistant product. These mechanical mixtures may react during final cure. Acrylonitrile–butadiene rubbers containing residual unsaturation can, however, be coreacted with phenolic resins during the early stages of polymerization if appropriate conditions are adopted. The coreaction probably occurs via formation of a chroman from a double bond in the rubber and an o-methylol phenol. The coreaction products are completely soluble in alcohol, whereas the rubbers are not. Laminates made from these coreaction products are flexibilized to the point at which they lend themselves well to cold punching. Yet the rubber, being tightly bound, cannot be extracted with solvents nor lead to blistering on heating.