Kinetics studies of the OH-initiated oxidation of 2-butyne, propyne, and acetylene were conducted at 100 Torr and 298 K using turbulent flow chemical ionization mass spectrometry. The major oxidation products were identified, and with the aid of supporting electronic structure thermodynamics calculations, a general OH-initiated oxidation mechanism for the alkynes is proposed. The major product ...

The photodissociation dynamics of propyne and allene are investigated in two molecular beam/ photodissociation instruments, one using electron impact ionization and the other using tunable vacuum ultraviolet ~VUV! light to photoionize the photoproducts. The primary dissociation channels for both reactants are C3H31H and C3H21H2. Measurement of the photoionization efficiency curves on the VUV in...

THE TITLE COMPOUND [SYSTEMATIC NAME: 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra-propyn-yloxy-2,8,14,20-tetra-thia-calix[4]arene], C(52)H(56)O(4)S(4), is an alkyl-ated product bearing four propyne groups at the lower rim of a 5,11,17,23-tetra-tert-butyl-tetrathia-calix[4]arene. The mol-ecule is located on a crystallographic twofold rotation axis, running through two S atoms and perpendicular ...

The reaction of ground state boron atoms, 11B(2Pj), with allene, H2CCCH2(X1A1), was studied under single collision conditions at a collision energy of 21.5 kJ mol(-1) utilizing the crossed molecular beam technique; the experimental data were combined with electronic structure calculations on the 11BC3H4 potential energy surface. The chemical dynamics were found to be indirect and initiated by a...

Self-consistent periodic slab calculations based on gradient-corrected density functional theory (DFT-GGA) have been conducted to examine the reaction network of propane dehydrogenation over close-packed Pt(111) and stepped Pt(211) surfaces. Selective C-H or C-C bond cleaving is investigated to gain a better understanding of the catalyst site requirements for propane dehydrogenation. The energy...

The electronic excitation spectra of propyne and 1-butyne have been investigated by the method of variable angle electron-impact spectroscopy. In both molecules, two singlet--;triplet transitions were observed with maximum intensities at 5.2 and 5.85 eV. No evidence was found for the existence of any transitions with vertical excitation energy below 5 eV. A number of previously unreported trans...

We studied the reaction of phenyl radicals (C(6)H(5)) with 1,3-butadiene (H(2)CCHCHCH(2)) exploiting a high temperature chemical reactor under combustion-like conditions (300 Torr, 873 K). The reaction products were probed in a supersonic beam by utilizing VUV radiation from the Advanced Light Source and by recording the experimental PIE curves at mass-to-charge ratios of m/z = 130 (C(10)H(10)(...

Photodissociation of methane at high altitude levels in Neptune's atmosphere leads to the production of complex hydrocarbon species such as acetylene (C2H2), ethane (C2H6), methylacetylene (CH3C2H), propane (C3H8), diacetylene (C4H2), and butane (C4H8). These gases diffuse to the lower stratosphere where temperatures are low enough to initiate condensation. Particle formation may not occur re...

Infrared (IR) spectra of the hydrocarbon ices C3H8 (propane), C3H6 (propylene, propene), and C3H4 (propyne, methylacetylene) are relevant to study low-temperature chemistry spectroscopy objects within beyond Solar System, but IR band strengths absorption coefficients lacking for these compounds. Here we present new crystalline non-crystalline forms C3H8, C3H6, C3H4. Measurements ice density ref...

Parahydrogen-induced polarization was observed in the gas phase heterogeneous hydrogenation of propyne catalyzed by Pd(0) nanoparticles embedded in an ionic liquid phase supported on activated carbon fibers (Pd(0)/SILP/ACF). The results were markedly different from those obtained with a reference catalyst, Pd(0)/ACF, demonstrating the important role of the ionic liquid.