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Improvement of Selectivity in Acetylene Hydrogenation with Comparable Activity over Ordered PdCu Cat
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A cyclic electrochemical strategy to produce acetylene from CO 2 , CH 4 , or alternative carbon sources
This paper presents the first combined measurement of the double-differential muon neutrino and antineutrino charged-current cross sections with no pions in the final state on hydrocarbon at the off-axis near detector of the T2K experiment. The data analyzed in this work comprise 5.8 × 10$^{20}$ and 6.3 × 10$^{20}$ protons on target in neutrino and antineutrino mode respectively, at a beam energy peak of 0.6 GeV. Using the two measured cross sections, the sum, difference, and asymmetry were calculated with the aim of better understanding the nuclear effects involved in such interactions. The extracted measurements have been compared with the prediction from different Monte Carlo generators and theoretical models showing that the difference between the two cross sections have interesting sensitivity to nuclear effects.
Adsorption properties of acetylene, ethylene and ethane in UiO-66 with linker defects and NO 2 functionalization
Using calorimetry and ab initio simulations, we uncover atomic-level details of the loading/separation process of C 2 hydrocarbons in UiO-66.
Binding of carbon dioxide and acetylene to free carboxylic acid sites in a metal–organic framework
The functionalisation of organic linkers in metal–organic frameworks (MOFs) to improve gas uptake is well-documented. Although the positive role of free carboxylic acid sites in MOFs for binding gas molecules has been proposed in computational studies, relatively little experimental evidence has been reported in support of this. Primarily this is because of the inherent synthetic difficulty to prepare MOF materials bearing free, accessible –COOH moieties which would normally bind to metal ions within the framework structure. Here, we describe the direct binding of CO 2 and C 2 H 2 molecules to the free –COOH sites within the pores of MFM-303(Al). MFM-303(Al) exhibits highly selective adsorption of CO 2 and C 2 H 2 with a high selectivity for C 2 H 2 over C 2 H 4 . In situ synchrotron X-ray diffraction and inelastic neutron scattering, coupled with modelling, highlight the cooperative interactions of adsorbed CO 2 and C 2 H 2 molecules with free –COOH and –OH sites within MFM-303(Al), thus rationalising the observed high selectivity for gas separation.
Selective chemical looping combustion of acetylene in ethylene-rich streams
Here, the requirement for C 2 H 2 concentrations below 2 parts per million (ppm) in gas streams for C 2 H 4 polymerization necessitates its semihydrogenation to C 2 H 4 . Here, we demonstrate selective chemical looping combustion of C 2 H 2 in C 2 H 4 -rich streams by Bi 2 O 3 as an alternative catalytic pathway to reduce C 2 H 2 concentration below 2 ppm. Bi 2 O 3 combusts C 2 H 2 with a first-order rate constant that is 3000 times greater than the rate constant for C 2 H 4 combustion. In successive redox cycles, the lattice O of Bi 2 O 3 can be fully replenished without discernible changes in local Bi coordination or C 2 H 2 combustion selectivity. Heterolytic activation of C–H bonds across Bi–O sites and the higher acidity of C 2 H 2 results in lower barriers for C 2 H 2 activation than C 2 H 4 , enabling selective catalytic hydrocarbon combustion leveraging differences in molecular deprotonation energies.
Interaction of methane, ethane, ethylene, and acetylene with an iron /001/ surface and their influence on adhesion studied with LEED and Auger
Adhesion studies of iron surfaces with adsorbed hydrocarbons
Extracting a History of Global Fire Emissions for the Past Millennium From Ice Core Records of Acetylene, Ethane, and Methane
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Photodissociation of acetylene and bromoacetylene in the vacuum ultraviolet - Production of electronically excited C2H and C2
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Absolute rate constant for the reaction of atomic hydrogen with acetylene over an extended pressure and temperature range
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Noninvasive determination of cardiac output by a modified acetylene rebreathing procedure utilizing mass spectrometer measurements
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The abundance of acetylene in the atmosphere of Jupiter
The Q and R branches of the C2H2 nu(5) fundamental, observed in emission in an aircraft spectrum of Jupiter near 750/cm, have been analyzed with the help of an improved line listing for this band. The line parameters have been certified in the laboratory with the same interferometer used in the Jovian observations. The maximum mixing ratio of C2H2 is found to be between 5 times 10 to the -8th and 6 times 10 to the -9th power, depending on the form of its vertical distribution and the temperature structure assumed for the lower stratosphere. Most consistent with observations of both Q and R branches are: (1) distributions of C2H2 with a constant mixing ratio in the stratosphere and a cutoff at a total pressure of 100 mbar or less, and (2) the assumption of a temperature at 0.01 bar which is near 155 K.
Photochemistry of acetylene - Bimolecular rate constant for the formation of butadiyne and reactions of ethynyl radicals
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Mixing ratios of methane, ethane, and acetylene in Neptune's stratosphere
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Elastic scattering and rotational excitation of a polyatomic molecule by electron impact - Acetylene
Differential, integral, momentum transfer, and partial cross sections have been calculated for elastic scattering and rotational excitation of C2H2 by 10-eV electrons. The effective potential includes static, exchange, and polarization interactions calculated by the INDOX/1s method and the semiclassical exchange approximation with adiabatic polarization at large electron-molecule distances. The scattering is treated by well converged rotational close coupling using the centrifugal dominant scheme to select the channels included and including up to 32 coupled channels for a given total angular momentum. The calculated integral cross sections for pure elastic scattering and rotation excitation are 54.5 and 41.4 a(0)squared, respectively. These are much larger than the values (34.4 and 18.6 a(0)squared) previously (Onda and Truhlar, 1979) calculated for the isoelectronic molecule N2, at this energy. This illustrates how the greater spatial extent of C2H2 greatly increases the cross sections for pure elastic and rotationally inelastic scattering.
Identification of acetylene /C2H2/ in infrared atmospheric absorption spectra
Infrared atmospheric absorption spectra at 0.02/cm resolution were obtained during a balloon flight on March 23, 1981 from the Holloman AFB, New Mexico. The absorption features, attributed to C2H2, were used to derive a preliminary mixing ratio of about 25 pptv near 9 km, accurate to + or - 40%. This mixing ratio falls into the range of values calculated for the upper troposphere C2H2 in a photochemical/transport model. However, previous measurements from aircraft grab sampling (Cronn and Robinson, 1979) show four to twelve times this C2H2 concentration 1.5 km below the tropopause.