15364-23-5Relevant academic research and scientific papers
Laser-initiated chemical chain reactions
Nesbitt, David J.,Leone, Stephen R.
, p. 1722 - 1732 (1980)
A detailed kinetic and experimental analysis is presented for chemical chain reaction processes initiated by well-controlled, low power laser pulses.Realtime evolution of the chain reaction is followed by direct detection of infrared chemiluminescence from vibrationally excited HCl product molecules produced by one of the propagation reactions in the chain.By appropriate choice of conditions, the chain reactions may be analyzed separately for pseudofirst-order, radical-reagent processes as well as for second-order, radical-radical events.The pulsed laser initiation technique is applied to three sample chain systems which exhibit distinctly different chain lengths, rates, and termination behaviors.These systems are Cl2/H2S, Cl2/H2, and Cl2/CH3SH.In the case of Cl2/H2S, detailed rate constant data are obtained for the fundamental chain propagation steps, and appropriate chain termination steps are assigned from the observations.The results demonstrate a new, general technique for the quantitative study of chemical chain reactions and related combustion processes.
Direct determination of the spin-orbit reactivity in CI(2P3/2, 2P1/2) + H2/D2/HD reactions
Dong,Lee,Liu
, p. 1197 - 1204 (2001)
Relative cross sections of the two spin orbit states in the Cl(2P)+H2 reeaction systems was presented. Large nonadiabatic reactivity was brought about by comparing the double differential cross sections of this reaction from the two
Heterogeneous Reaction of HNO3(g) + NaCl(s) -> HCl(g) + NaNO3(s) and N2O5(g) + NaCl(s) -> ClNO2(g) + NaNO3(s)
Leu, Ming-Taun,Timonen, Raimo S.,Keyser, Leon F.,Yung, Yuk L.
, p. 13203 - 13212 (1995)
The hetrogeneous reactions of HNO3(g) + NaCl(s) -> HCl(g) + NaNO3(s) (eq 1) and N2O5(g) + NaCl(s) -> ClNO2(g) + NaNO3(s) (eq 2) were investigated over the temperature range 223-296 K in a flow-tube reactor coupled to a quadrupole mass spectrometer.Either a chemical ionization mass spectrometer (CIMS) or an electron-impact ionization mass spectrometer (EIMS) was used to provide suitable detection sensitivity and selectivity.In order to mimic atmospheric conditions, partial pressures of HNO3 and N2O5 in the range 6 x 10-8 ca. 2 x 10-6 Torr were used.Granule sizes and surface roughness of the solid NaCl substrates were determined by us ing a scanning electron microscope.For dry NaCl substrates, decay rates of HNO3 were used to obtain γ(1) = 0.013 +/- 0.004 (1?) at 296 K and >0.008 at 223 K, respectively.The error quoted is the statistical error.After all corrections were made, the overall error, including systematic error, was estimated to be about a factor of 2.HCl was found to be the sole gas-phase product of reaction 1.The mechanism changed from heterogeneous reaction to predominantly physical adsorption when the reactor was cooled from 296 to 223 K.For reaction 2 using dry salts, γ(2) was found to be less then 1.0 x 10-4 at both 223 and 296 K.The gas-phase reaction product was identified as ClNO2 in previous studies using an infrared spectrometer.An emhancement in reaction probability was observed if water was not completely removed from salt surfaces, probably due to the reaction of N2O5(g) + H2O(s) -> 2HNO3(g).Our results are compared with previous literature values obtained using diferent experimental techniques and conditions.The implications of the present results for the enhancement of the hydrogen chloride column density in the lower stratosphere after EI Chichon volcanic eruption and for the chemistry of HCl and HNO3 in the marine troposphere are discussed.
Influence of atmosphere kind on temperature programmed decomposition of noble metal chlorides
Jó?wiak, Wojciech K.,Maniecki, Tomasz P.
, p. 151 - 161 (2005)
The hydrated chlorides of noble metals located in the 8-10 groups of Periodic System were used in this work: Ru, Rh, Pd, Ir and Pt. The common mechanism of chloride compounds decomposition in oxidative, inert and reductive atmospheres was postulated and mutual similarities and differences were discussed. These compounds play a significant role in heterogeneous catalysis, as starting materials for metal/oxide catalysts, and also in analytical chemistry and industry.
New organotin and organosilicon derivatives of P/As/Sb/Bi-polyoxotungstates
Rusu, Mariana,Tomsa, Adrian R.,Rusu, Dan,Haiduc, Ionel
, p. 951 - 965 (1999)
Mono- or bis(organoelement)-substituted Keggin molybdotungstophosphates K4[C6H5SnPMo2W9O 39]·14H2O, K4[C4H9SnPMo2 W9O3
In situ monitoring of the NaCl + HNO3 surface reaction: The observation of mobile surface strings
Zangmeister, Christopher D.,Pemberton, Jeanne E.
, p. 8950 - 8953 (1998)
The reaction of single-crystal NaCl(100) with dry HNO3 was monitored using atomic force microscopy in contact mode. Initial exposure to dry HNO3 results in the growth of a two-dimensional metastable layer of NaNO3 to nearly complete surface coverage. Exposure of this metastable NaNO3 layer to small amounts of H2O produces deliquescence of the surface with concomitant rearrangement of the NaNO3 adlayer to form unusual mobile strings presumed to contain NaNO3. These strings are transient and eventually crystallize to form rhombohedral NaNO3 crystals sitting on top of the NaCl surface.
Neon matrix-isolation infrared spectrum of HOOCl measured upon the VUV-light irradiation of an HCl/O2 mixture
Yoshinobu, Takeo,Akai, Nobuyuki,Kawai, Akio,Shibuya, Kazuhiko
, p. 70 - 74 (2009)
Vacuum ultraviolet (VUV) photolysis of an HCl/O2 mixture has been carried out to identify HOOCl by the Ne matrix-isolation infrared spectroscopy with the aid of quantum chemical calculations. Newly-observed IR bands at 823, 1363 and 3542 cm-1 are assigned to those of HOOCl on the basis of the isotope shifts with DOOCl and the CCSD(T)/aug-cc-pVDZ calculation. The observed dependence of band intensities on the time of VUV photolysis indicates that HOOCl and HOClO are the photoproducts formed in an early stage. In addition, HOOCl is found to decompose to form HCl in the UV photolysis (λ ≥ 365 nm), which consists with the S1-S0 energy separation estimated by the TDDFT method.
Laser-photolysis/time-resolved Fourier-transform absorption spectroscopy: Formation and quenching of HCl(v) in the chain reaction Cl/Cl2/H2
Eberhard, Juerg,Yen, Pey-Shiun,Lee, Yuan-Pern
, p. 6499 - 6502 (1997)
A system to measure time-resolved Fourier-transform infrared absorption spectra of gaseous samples using a commercial step-scan spectrometer is described. To increase the signal intensity, the incident infrared light is multipassed within a White cell. Light from a photolysis laser passes through the reaction cell to initiate the reaction in the flowing gaseous sample. The variation of absorbance is obtained from the ac-coupled signal whereas phase information and a reference spectrum are from the dc-coupled signal. The system is tested by probing the temporal evolution of HCl(v) in the chain reaction of H2 and Cl2 initiated by photolysis at 355 nm. Time-resolved absorption spectra of HCl(v=0-2) were obtained with spectral resolution 0.75 cm-1 and intervals down to 5 μs. Kinetic modeling of deduced temporal profiles of HCl(v=0-2) yields rate coefficients of (1.38+0.04) × 10-14 and (5.8±0.4) × 10-15 cm3 molecule-1 s-1 (in which error limits represent only the uncertainty of the fit) for reactions Cl+H2→HCl(v=0)+H and Cl+H2→HCl(v=1)+H, respectively; the total rate coefficient is in agreement with previous kinetic measurements.
Statistical methodology for the detection of small changes in distances by EXAFS: Application to the antimalarial ruthenoquine
Curis, Emmanuel,Dubar, Faustine,Nicolis, Ioannis,Benazeth, Simone,Biot, Christophe
, p. 5577 - 5585 (2012)
Antimalarial compounds ruthenoquine and methylruthenoquine were studied by X-ray absorption spectroscopy both in solid state and in solution, in normal (aqueous or CH2Cl2 solutions) and oxidative (aqueous solution with H2O2, either equimolar or in large excess) conditions, to detect small changes in the coordination sphere of the ruthenium atom. Since changes in the EXAFS spectra of these compounds are quite subtle, a complete procedure was developed to assess the different sources of uncertainties in fitted structural parameters, including the use of multivariate statistic methods for simultaneous comparison of edge energy correction ΔE0 and distances, which can take into account the very strong correlation between these two parameters. Factors limiting the precision of distance determination depend on the recording mode. In transmission mode, the main source of uncertainty is the data reduction process, whereas in fluorescence mode, experimental noise is the main source of variability in the fitted parameters. However, it was shown that the effects of data reduction are systematic and almost identical for all compounds; hence, they can be ignored when comparing distances. Consequently, for both fluorescence and transmission recorded spectra, experimental noise is the limiting factor for distance comparisons, which leads to the use of statistical methods for comparing distances. Univariate methods, focusing on the distance only, are shown to be less powerful in detecting changes in distances than bivariate methods making a simultaneous comparison of ΔE0 and distances. This bivariate comparison can be done either by using the Hotelling's T2 test or by using a graphical comparison of Monte Carlo simulation results. We have shown that using these methods allows for the detection of very subtle changes in distances. When applied to ruthenoquine compounds, it suggests that the implication of the nonbinding doublet of the aminoquine nitrogen in either protonation or methylation enhances the tilt of the two cyclopentadienyls. It also suggests that ruthenoquine and methylruthenoquine are, at least partially, oxidized in the presence of H2O2, with a small decrease in the Ru-C bond length and increase in the edge energy.
Photochemical Generation of the Optoacoustic Effect: An Acoustic Analogue of the Method of Intermittent Activation
O'Connor, M. T.,Stewart, R. B.,Diebold, G. J.
, p. 711 - 713 (1986)
When a mixture of H2 and Cl2 is irradiated with 488-nm radiation, the evolution of heat in the gas is governed by the rate of chain reaction.The optoacoustic effect, produced by modulating the amplitude of the radiation and recording the resulting acoustic signal, thus acts as a monitor of the chemical reaction rate in a manner analogous to the technique of intermittent activation.NO is shown to act as a potent inhibitor of the H2-Cl2 reaction by rapid reaction with Cl radicals.
