F:Flammable;
74-99-7Relevant articles and documents
Isomerization of Allene Propyne in Shock Waves and ab Initio Calculations
Kakumoto, Terumitsu,Ushirogouchi, Toshiaki,Saito, Ko,Imamura, Akira
, p. 183 - 189 (1987)
The isomerization allene propyne has been studied behind shock waves over the temperature range between 1300 and 2100 K and the total density range of (0.6-2.4) x 1E-5 mol/cm3.The isomerization rate was monitoring by means of the IR emission from allene and propyne.It was found that the process proceeded in the fall-off region, and the high-pressure limit rate constants were determined as k1 = 1E14.34 exp-1/(RT)> s-1, for the isomerization of allene to propyne, and k-1 = 1E14.14 exp-1/(RT)> s-1, for the isomerization of propyne to allene, using the equilibrium constants.Ab initio molecular orbital calculations have also been performed for the isomerization.It was found that the isomerization proceeded in a series of successive reactions via cyclopropene, which has been suggested by Honjou et al. (Honjou, N.; Pacansky, J.; Yoshimine, M.J.Am.Chem.Soc. 1984, 106, 5361).The rate constants estimated in terms of the transition-state theory, k1 = 1E14.23 exp-1/(RT)> s-1 and k-1 = 1E14.12 exp-1/(RT)> s-1, are consistent with the experimental results.
The isotope exchange reaction of fast hydrogen atoms with deuterated alkynes and alkenes
Johnston, Grace W.,Satyapal, Sunita,Bersohn, Richard,Katz, Benjamin
, p. 206 - 212 (1990)
The exchange reaction H (1 eV) + RD -> RH + D, where RD was deuterated acetylene, methylacetylene, ethylene, and propylene was studied by laser induced fluorescence detection of the hydrogen and deuterium atoms.The reaction cross sections were 1.69 +/- 0.
Novel tocopherol compounds IV. 5-tocopherylacetic acid and its derivatives
Rosenau, Thomas,Habicher, Wolf Dieter,Chen, Chen-Loung
, p. 787 - 798 (1996)
A new class of tocopherol (vitamin E) compounds, 5-tocopherylacetic acid derivatives, is presented. The synthesis and some unexpected properties of these compounds, such as relatively high thermal and chemical stability, are described and discussed in comparison with the labile 5a-halogeno-, 5a-alkoxy- or 5a-amino-substituted tocopherols.
Rearrangement of a Metal (η2-Alkyne) Complex to a Metal Vinylidene and Subsequent Reaction of the Metal Vinylidene to Regenerate the Alkyne
Bullock, R. Morris
, p. 165 - 167 (1989)
The η2-alkyne complex (C5H5)(PMe3)2Ru(HC(*)CMe)+PF6-, which was isolated from a reaction of HC(*)CMe with (C5H5)(PMe3)2RuCl, undergoes first-order rearrangement to give (C5H5)(PMe3)2Ru=C=C(H)Me+PF6-;
Kinetics of thermal gas-phase decomposition of 2-bromopropene using static system
Nisar, Jan,Awan, Iftikhar A.
, p. 1 - 5 (2007)
The gas phase elimination kinetics of 2-bromopropene was studied over the temperature range of 571-654 K and pressure range of 12-46 Torr using the seasoned static reaction system. Propyne was the only olefinic product formed and accounted for >98% of the reaction. This product was formed by homogeneous, unimolecular pathways with high-pressure first-order rate constant k∞ given by the equation k∞ = 10 13.47±0.6 exp-208.2±6.7(kj mol-1)/RT. The error limits are 95% certainty limits. The observed Arrhenius parameters are consistent with the four centered activated complex. The presence of methyl group on α-carbon lowers the activation energy by 41 kj mol-1.
Direct Evidence on the Mechanism of Methane Conversion under Non-oxidative Conditions over Iron-modified Silica: The Role of Propargyl Radicals Unveiled
?ot, Petr,Hemberger, Patrick,Pan, Zeyou,Paunovi?, Vladimir,Puente-Urbina, Allen,van Bokhoven, Jeroen Anton
supporting information, p. 24002 - 24007 (2021/10/01)
Radical-mediated gas-phase reactions play an important role in the conversion of methane under non-oxidative conditions into olefins and aromatics over iron-modified silica catalysts. Herein, we use operando photoelectron photoion coincidence spectroscopy to disentangle the elusive C2+ radical intermediates participating in the complex gas-phase reaction network. Our experiments pinpoint different C2-C5 radical species that allow for a stepwise growth of the hydrocarbon chains. Propargyl radicals (H2C?C≡C?H) are identified as essential precursors for the formation of aromatics, which then contribute to the formation of heavier hydrocarbon products via hydrogen abstraction–acetylene addition routes (HACA mechanism). These results provide comprehensive mechanistic insights that are relevant for the development of methane valorization processes.
Synthesis of Cyclopentenones with Reverse Pauson-Khand Regiocontrol via Ni-Catalyzed C-C Activation of Cyclopropanone
Jang, Yujin,Lindsay, Vincent N. G.
supporting information, p. 8872 - 8876 (2020/12/02)
A formal [3 + 2] cycloaddition between cyclopropanone and alkynes via Ni-catalyzed C-C bond activation has been developed, where 1-sulfonylcyclopropanols are employed as key precursors of cyclopropanone in the presence of trimethylaluminum. The transformation provides access to 2,3-disubstituted cyclopentenones with complete regiocontrol, favoring reverse Pauson-Khand products, where the large substituent is located at the 3-position of the ring. In the process, the trimethylaluminum additive is thought to play multiple roles, including as a Br?nsted base triggering the equilibration to cyclopropanone and liberation of methane, as well as a source of Lewis acid to activate the carbonyl group toward Ni-catalyzed C-C activation.
METHOD FOR PREPARATION OF NANOCERIA SUPPORTED ATOMIC NOBLE METAL CATALYSTS AND THE APPLICATION OF PLATINUM SINGLE ATOM CATALYSTS FOR DIRECT METHANE CONVERSION
-
Page/Page column 17, (2019/09/12)
Described are methods for converting methane to olefins, aromatics, or a combination thereof using a single atom catalyst comprising CeO2 nanoparticles impregnated with individual atoms of noble metals including Pt, Pd, Rh, Ru, Ag, Au, Ir, or a combination thereof. These single atom catalysts of the present invention are heated with methane to form olefins and aromatics.
Synthetic Studies Toward the Skyllamycins: Total Synthesis and Generation of Simplified Analogues
Giltrap, Andrew M.,Haeckl, F. P. Jake,Kurita, Kenji L.,Linington, Roger G.,Payne, Richard J.
, p. 7250 - 7270 (2018/06/01)
Herein, we report our synthetic studies toward the skyllamycins, a highly modified class of nonribosomal peptide natural products which contain a number of interesting structural features, including the extremely rare α-OH-glycine residue. Before embarking on the synthesis of the natural products, we prepared four structurally simpler analogues. Access to both the analogues and the natural products first required the synthesis of a number of nonproteinogenic amino acids, including three β-OH amino acids that were accessed from the convenient chiral precursor Garner's aldehyde. Following the preparation of the suitably protected nonproteinogenic amino acids, the skyllamycin analogues were assembled using a solid-phase synthetic route followed by a final stage solution-phase cyclization reaction. To access the natural products (skyllamycins A-C) the synthetic route used for the analogues was modified. Specifically, linear peptide precursors containing a C-terminal amide were synthesized via solid-phase peptide synthesis. After cleavage from the resin the N-terminal serine residue was oxidatively cleaved to a glyoxyamide moiety. The target natural products, skyllamycins A-C, were successfully prepared via a final step cyclization with concomitant formation of the unusual α-OH-glycine residue. Purification and spectroscopic comparison to the authentic isolated material confirmed the identity of the synthetic natural products.
METHOD FOR PRODUCING ACETYLENE COMPOUND
-
Paragraph 0043; 0050; 0051, (2017/02/23)
PROBLEM TO BE SOLVED: To provide a method for producing an acetylene compound. SOLUTION: A method for producing an acetylene compound comprises a first step of obtaining a cesium compound-supported alumina catalyst by burning a solid that is obtained by supporting a cesium compound on an alumina carrier at 150-400°C, and a second step of isomerizing an allene compound in the presence of the catalyst obtained in the first step. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
