676-80-2Relevant articles and documents
Tunneling chemical reactions in solid parahydrogen: A case of CD3+H2→CD3H+H at 5 K
Momose, Takamasa,Hoshina, Hiromichi,Sogoshi, Norihito,Katsuki, Hiroyuki,Wakabayashi, Tomonari,Shida, Tadamasa
, p. 7334 - 7338 (1998)
Ultraviolet photolysis of CD3I in solid parahydrogen at 5 K gives CD3 radical, which decreases in a single exponential manner with a rate constant of (4.7±0.5)×10-6 s-1. Concomitantly, CD3H is formed, which is accounted for by the quantum tunneling reaction CD3+H2→CD3H+H. Under the same conditions. CH3I yields CH3 radical, but the corresponding reaction between CH3 and H2, expected to give CH4+H, does not proceed measurably at 5 K. The difference between the two systems is attributed to the difference in the zero point energy change.
The inversion mechanism for the reaction H + CD4 --> CD3H + D
Chattopadhyay, Arun,Tasaki, Shintaro,Bersohn, Richard,Kawasaki, Masahiro
, p. 1033 - 1036 (1991)
The reaction H+CD4CHD3+D is shown to take place by an inversion mechanism.The evidence is as follows.When the H atom has an anisotropic (perpendicular) velocity distribution is also perpendicular.For a relative energy near 2 eV, the reaction cross section for H+CD4 is 0.084+/0.014A2 and for H+CH3D is 0.040+/-0.015A2.At the same H atom energy, when CH3CD3 is substituted for CD4, no D atoms can be detected.Finaly, around 80percent of the initial H atom kinetic energy is released as kinetic energy of the D atom showing that the reaction is nearly vibrationally adiabatic.
Kinetics and Thermochemistry of the CH3, C2H5, and i-C3H7. Study of the Equilibrium R + HBr R-H + Br
Russell, John J.,Seetula, Jorma A.,Gutman, David
, p. 3092 - 3099 (1988)
The kinetics of the reactions between CH3, C2H5, and i-C3H7 with HBr were studied in a tubular reactor coupled to a photoionization mass spectrometer.Rate constants were measured as a functio of temperature to determine Arrhenius parameters.The following rate constant expressions were obtained (units of the preexponential factors are cm3 molecule-1 s-1 and those of the activation energies are kJ mol-1; the temperature range covered in each study is also indicated): CH3 + HBr ; C2H5 + HBr ; i-C3H7 + HBr .These results were combined with determinations of the reverse rate constants to obtain equilibrium constants for the reactions R + HBr R-H + Br.Second-law-based analyses yielded heats of formation and entropies of CH3, C2H5, and i-C3H7 that are in close agreement with recent determinations of heats of formation in prior investigations of dissociation-recombination equilibria and calculations of entropies.The observed negative activation energies for R + HBr reactions (and negative activation energies inferred for R + I2 reactions from the current results) provide the basis for a detailed explanation for the disparities that currently exist between heats of formation of alkyl radicals that have been obtained from studies of bromination and iodination kinetics and those that are derived from kinetic studies of other reactions.A complex mechanism for R + HBr reactions that is consistent with the observed kinetic behavior of these reactions is discussed.
Dynamics of formation of products D2CN+, DCN +, and CD3+ in the reaction of N+ with CD4: A crossed-beam and theoretical study
Zabka, Jan,Roithova, Jana,Spanel, Patrik,Herman, Zdenek
, p. 1384 - 1391 (2010)
The formation of D2CN- in the reaction of N - (3P) with CD4 was studied using the crossed beam technique at collision energies of 3.66 and 4.86 eV. The experiments were complemented by calculations of stationary points on the triplet hypersurface of the system. The scattering data snowed that the reaction proceeds by the formation of two intermediate complexes having different lifetimes: a long-lived statistical intermediate and a short-lived complex (mean lifetime about one period of an average rotation) with more energy in translation than the statistical complex. Comparison with theoretical calculations suggests that the long-lived complex leads the CDND+ isomer of the product ion, whereas the short-lived complex leads prevailingly to the CD2N- isomer. The product DCN+ results from further decomposition of the primary product D2CN-, whereas CD3- is formed both by a hydride-ion transfer and a long-lived complex decomposition.
Platinum catalyzed c-h activation and the effect of metal-support interactions
Sattler, Aaron,Paccagnini, Michele,Lanci, Michael P.,Miseo, Sabato,Kliewer, Chris E.
, p. 710 - 720 (2020/01/02)
Catalytic C-H bond activation of methane and ethane on a series of silica supported platinum catalysts (Pt/SiO2) was studied by using hydrogen/deuterium (H/D) exchange. Kinetic experiments demonstrate that under the reaction conditions studied, the rate of C-H bond activation shows approximate first order dependence in alkane and inverse first order dependence in D2. The rate of C-H activation is affected by the presence of sodium on the silica support, where sodium-free supports have the fastest rates of C-H activation, as assessed by H/D exchange. CO adsorption and FTIR studies indicate that the Pt particles on the sodium-free support are more electron-deficient, having the most blue-shifted linear CO stretch, while sodium-containing supports are more electron-donating, having the most red-shifted linear CO stretch. It is proposed, based on the results described in this article and previous work in the literature, that more electron-donating supports cause the Pt particles to be more electron-rich and to adsorb D? (or H*) more strongly, thereby stabilizing the ground state and resting state of the catalyst, resulting in a decreased rate of C-H activation.
Catalytic Activation of Unstrained, Nonactivated Ketones Mediated by Platinum(II): Multiple C-C Bond Cleavage and CO Extrusion
Sarju, Julia P.,Dey, Debashish,Torroba, Javier,Whitwood, Adrian C.,Redeker, Kelly,Bruce, Duncan W.
supporting information, p. 4539 - 4542 (2019/11/29)
The complexes [Pt(tolpy)Cl(L)] (tolpy = 2-(4-tolyl)pyridyl; L = dmso, dms, py, PPh3, CO) are precursors for the catalytic cleavage of C-C bonds and extrusion of CO from a series of unactivated ketones such as cyclohexanone; deuterium labeling experiments demonstrate the involvement of a transfer hydrogen step in the mechanism.
Photocatalytic halohydrocarbon dehalogenation conversion method
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Paragraph 0101; 0102, (2019/04/02)
The invention provides a photocatalytic halohydrocarbon dehalogenation conversion method which comprises the following steps: adding a photocatalyst quantum dot/rod into a solvent to obtain a solutionA; adding halohydrocarbon and an electronic sacrificial body into the solution A to obtain a solution B; utilizing a light source to irradiate the solution B and catalyzing the solution B to performhalohydrocarbon dehalogenation conversion. According to the photocatalytic halohydrocarbon dehalogenation conversion method disclosed by the invention, a nano quantum dot and a nano quantum rod are applied to dehalogenation conversion reaction of alkyl halide, alkenyl halide and alkyne halide for the first time; the reaction conditions are moderate, visible light is utilized as driving energy, a product is hydrocarbon compound, and the whole process has the advantages of environmental protection, conciseness and high efficiency. In addition, higher hydrocarbon of carbon chain growth can be generated after dehalogenation reaction, so that the method has potential application in preparation of higher hydrocarbon. According to the method disclosed by the invention, halohydrocarbon dehalogenation conversion and deuteration marking processes are jointly performed; hydrocarbon deuteration marking can be finished when a halohydrocarbon dehalogenation process is finished. The invention furtherprovides a method for performing deuteration marking on hydrocarbon.
Accessing the Nitromethane (CH3NO2) Potential Energy Surface in Methanol (CH3OH)-Nitrogen Monoxide (NO) Ices Exposed to Ionizing Radiation: An FTIR and PI-ReTOF-MS Investigation
Góbi, Sándor,Crandall, Parker B.,Maksyutenko, Pavlo,F?rstel, Marko,Kaiser, Ralf I.
, p. 2329 - 2343 (2018/03/21)
(D3-)Methanol-nitrogen monoxide (CH3OH/CD3OH-NO) ices were exposed to ionizing radiation to facilitate the eventual determination of the CH3NO2 potential energy surface (PES) in the condensed phase. R
High-temperature Shilov-type methane conversion reaction: Mechanistic and kinetic studies
Kang, Shujuan,Ma, Qisheng,Chen, Weiqun,Chen, Guanyi,Tang, Yongchun
, p. 1777 - 1784 (2015/10/20)
Traditional Shilov reactions (performed in aqueous solution with a PtCl2 catalyst) for methane conversion suffer from catalyst deactivation at high temperatures (> 100 °C), therefore only very low conversion rates have been achieved. In this paper, we show that Shilov-type C-H activations are achievable at much higher temperatures (～200 °C) by addition of concentrated aqueous solutions of Cl- to inhibit Pt catalyst precipitation. Various chloride-based ionic liquids also stabilized the Pt catalyst at mild reaction temperatures (～140 °C). Under high-pressure conditions (> 25.5 MPa), achieved using a specially designed sealed gold-tube reactor, very high methane conversion rates (> 90%) were obtained; this is attributed to the improved methane solubility in aqueous solution. Deuterium isotope (H/D) exchange between methane and water was used to examine the reaction reactivity and selectivity. Multiply D-substituted products were observed, indicating that multiple C-H activations occurred. A comprehensive network reaction that included all the chain reactions was set up to clarify the reactivities and product selectivities of the methane activation reactions. The reaction network consisted of a series of parallel first-order reactions, which can be described by the Arrhenius equation. The kinetic parameters such as the frequency factor, activation energies, and stoichiometric coefficients were obtained by fitting the experimental data. Because all four C-H bonds in a methane molecule are equivalent, multiple substitutions during methane conversion cannot be avoided. Our studies indicate that mono-substituted and di-substituted methane isotopologue generations have similar activation energies, suggesting that the highest mono-substitution selectivity cannot be greater than 50%.
Methylene migration and coupling on a non-reducible metal oxide: The reaction of dichloromethane on stoichiometric α-Cr2O3(0001)
Dong, Yujung,Brooks, John D.,Chen, Tsung-Liang,Mullins, David R.,Cox, David F.
, p. 28 - 38 (2015/02/02)
The reaction of CH2Cl2 over the nearly-stoichiometric α-Cr2O3(0001) surface produces gas phase ethylene, methane and surface chlorine adatoms. The reaction is initiated by the decomposition of CH2Cl2 into surface methylene and chlorine. Photoemission indicates that surface cations are the preferred binding sites for both methylene and chlorine adatoms. Two reaction channels are observed for methylene coupling to ethylene in temperature-programmed desorption (TPD). A desorption-limited, low-temperature route is attributed to two methylenes bound at a single site. The majority of ethylene is produced by a reaction-limited process involving surface migration (diffusion) of methylene as the rate-limiting step. DFT calculations indicate the surface diffusion mechanism is mediated by surface oxygen anions. The source of hydrogen for methane formation is adsorbed background water. Chlorine adatoms produced by the dissociation of CH2Cl2 deactivate the surface by simple site-blocking of surface Cr3 + sites. A comparison of experiment and theory shows that DFT provides a better description of the surface chemistry of the carbene intermediate than DFT+U using reported parameters for a best representation of the bulk electronic properties of α-Cr2O3.
