F+:Highly flammable;
74-86-2Relevant articles and documents
Jenkins, W. J.
, p. 747 - 749 (1921)
High-Temperature Stabilities of Hydrocarbons
Stein, S. E.,Fahr, A.
, p. 3714 - 3725 (1985)
A chemical thermodynamic analysis of hydrocarbon molecules from 1500 to 3000 K is presented for species C2nH2m, n=1-21, m=1-8.With group additivity as the primary estimation method, the nature and chemical thermodynamic properties of the most stable molecules ( stabilomers ) are found.Concentrations of these molecules are then examined in equilibrium with acetylene and molecular hydrogen after taking into account numbers of isomers.Thermodynamically favored pathways leading to large, condensed polyaromatic species are examined in detail.Two general types of paths are found.At higher H2/C2H2 ratios (>=1), most species on these paths are polycyclic aromatic molecules and, depending on partial pressures of C2H2 and H2, a free energy barrier appears in the range 1400-1800 K which increases sharply with increasing temperature.At lower H2/C2H2 ratios, many smaller species are cyclic, and as this ratio becomes smaller the barrier declines and becomes less sensitive to temperature.A brief dicussion of the connection between these results and the kinetics of carbon polymerization is then presented.
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Currell,Zechmeister
, p. 205 (1958)
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Reactions of vinyl radicals at high temperatures: Pyrolysis of vinyl bromide iodide and the reaction H + C2D2 → D + C2HD
Rao,Skinner, Gordon B.
, p. 6313 - 6319 (1988)
Five sets of experiments were carried out to determine the rate constant for dissociation of C2H3 at high temperatures. In all cases the measurements involved absorption of H or D Lyman-α radiation in argon-diluted gas mixtures reacting behind shock waves. For pyrolysis of vinyl bromide at 0.5-atm total pressure we found for C2H3 + Ar → C2H2 + H + Ar, k = 7.0 × 1013 exp(-28 kcal/RT) mol-1 cm3 s-1 at 1380-1750 K. For the same reaction initiated from vinyl iodide at 0.5-atm total pressure and 1060-1370 K, we found k = 3.5 × 1014 exp(-33 kcal/RT) mol-1 cm3 s-1. In three sets of experiments in which H atoms reacted with C2D2 to produce D atoms, we obtained values of k∞ for the reaction H + C2H2 → C2H3 of 8 × 1011, 1.2 × 1012, and 3.4 × 1012 mol-1 cm3 s-1 in the temperature range 1200-1900 K, with no clearly visible temperature dependence. All of the experimental values lie 3-10 times lower than those deduced from earlier work at high temperatures or based on ab initio calculations for the vinyl radical.
Cazeneuve
, (1884)
Callear,Robb
, p. 21 (1954)
Peters,Kuester
, (1931)
Thermal Decomposition of Energetic Materials. 25. Shifting of the Dominant Decomposition Site by Backbone Substitution of Alkylammonium Nitrate Salts
Oyumi, Y.,Brill, T. B.
, p. 3657 - 3661 (1987)
Exchanging X = -C(NO2)2F for X = -C(NO2)3 causes the dominating fast thermal decomposition site in NO3 salts to shift from largely that of the C-NO2 bond to largely that of the -H+...NO3- portion.This is consistent with an order of thermal stability of the energetic sites in these salts of -C(NO2)2F>-H+...NO3->-C(NO2)3.These conclusions were drawn from the nature of the IR-active gas products that are evolved in real time upon fast thermolysis (>100 K s-1) and from slow heating of the condensed phase.The O/H ratio of the parent primary ammonium salt appears to be a qualitative indicator of whether NH3(g) will formed under these conditions.Salts with O/H >/= 1 have not been observed to release NH3(g) while those with O/H 1 do.The salt with X=-C(NO2)2F possesses four polymorphs between 297 K and its two melting points.Only two polymorphs are present when X = -C(NO2)3.
Surface kinetics using line of sight techniques: The reaction of chloroform with Cu(111)
Jones, Robert G.,Clifford, Charles A.
, p. 5223 - 5228 (1999)
The adsorption of chloroform (CHCl3) on Cu(111) in the temperature range 100-480 K has been studied using line of sight sticking probability (LOSSP) measurements, line of sight temperature programmed desorption (LOSTPD), low energy electron diffraction (LEED), He I ultra-violet photoelectron spectroscopy (UPS) and work function measurements. Chloroform adsorbs molecularly at 100 K with a sticking probability of 0.98 ± 0.02, the monolayer reacting on heating to 170 K to form chemisorbed chlorine and adsorbed ethyne. The adsorbed ethyne desorbs at just above room temperature with first order kinetics, an activation energy of 77 ± 6 kJ mol-1 and a pre-exponential factor of 10(11±1) s-1. The sticking probability of chloroform on clean Cu(111) at 320 K is 0.23 ± 0.04, which corresponds to activated adsorption at zero coverage with an activation energy of 3.5 ± 0.7 kJ mol-1. The initial sticking probability is found to increase slightly for temperatures above room temperature, and also for temperatures below room temperature, while the sticking probability at finite coverage is greatly increased by the presence of the dissociation product, ethyne, on the surface. These observations are explained in terms of activated adsorption at zero coverage which becomes non-activated at finite coverage due to attractive intermolecular interactions between adsorbed chloroform molecules, and adsorbed chloroform and ethyne molecules.
Beletskaya et al.
, p. 485 (1969)
Burns,Reed
, p. 101,107 (1963)
Stief,Decarlo
, p. 839 (1969)
Nicholas et al.
, p. 1610,1611 (1966)
Formation of Acetylene in the Reaction of Methane with Iron Carbide Cluster Anions FeC3? under High-Temperature Conditions
Li, Hai-Fang,Jiang, Li-Xue,Zhao, Yan-Xia,Liu, Qing-Yu,Zhang, Ting,He, Sheng-Gui
, p. 2662 - 2666 (2018)
The underlying mechanism for non-oxidative methane aromatization remains controversial owing to the lack of experimental evidence for the formation of the first C?C bond. For the first time, the elementary reaction of methane with atomic clusters (FeC3?) under high-temperature conditions to produce C?C coupling products has been characterized by mass spectrometry. With the elevation of temperature from 300 K to 610 K, the production of acetylene, the important intermediate proposed in a monofunctional mechanism of methane aromatization, was significantly enhanced, which can be well-rationalized by quantum chemistry calculations. This study narrows the gap between gas-phase and condensed-phase studies on methane conversion and suggests that the monofunctional mechanism probably operates in non-oxidative methane aromatization.
Photodissociation of 1,2-C2H2Br2 at 248 nm: Competition between three-body formation Br+Br+C2H2 and molecular Br2 elimination
Lee,Chou,Lee,Wang,Lin
, p. 3195 - 3200 (2001)
The photodissociation of 1,2-C2H2Br2 was studied using product translational spectroscopy. A detector consisting of an electron impact ionizer, quadrupole mass filter and Daly type ion counter was used to measure the dissociation production after travelling a flight path of 365 mm from the reaction zone. Experimental analysis suggested that the dissociation of the molecule into triple products was due to an asynchronous concerted reaction. Behavior of the molecule in the presence of additional bromine atom and the molecular elimination of Br2 were also studied. The product anisotropy indicated that both Br fragments were produced in a fraction of rotational period.
The synthesis of ternary acetylides with tellurium: Li2TeC2 and Na2TeC2
Németh, Károly,Unni, Aditya K.,Kalnmals, Christopher,Segre, Carlo U.,Kaduk, James,Bloom, Ira D.,Maroni, Victor A.
, p. 55986 - 55993 (2015)
The synthesis of ternary acetylides Li2TeC2 and Na2TeC2 is presented as the first example of ternary acetylides with metalloid elements instead of transition metals. The synthesis was carried out by the direct reaction of the corresponding bialkali acetylides with tellurium powder in liquid ammonia. Alternatively, the synthesis of Na2TeC2 was also carried out by the direct reaction of tellurium powder and two equivalents of NaC2H in liquid ammonia leading to Na2TeC2 and acetylene gas through an equilibrium containing the assumed NaTeC2H molecules besides the reactants and the products. The resulting disordered crystalline materials were characterized by X-ray diffraction and Raman spectroscopy. Implications of these new syntheses on the synthesis of other ternary acetylides with metalloid elements and transition metals are also discussed.
Miller,Noyes
, p. 3403 (1952)
Evidence for a difference in the dissociation mechanisms of acetylene (HCCH) and vinylidene (H2C=C:) from charge inversion mass spectrometry
Hayakawa, Shigeo,Tomozawa, Kouji,Takeuchi, Takae,Arakawa, Kazuo,Morishita, Norio
, p. 2386 - 2390 (2003)
Vinylidene and acetylene are the simplest hydrocarbon isomers, and vinylidene is the simplest unsaturated carbene. The charge inversion mass spectra of C2H2+ cations derived from acetylene using Na, K, Rb and Cs targets were found to be clearly different from those derived from vinylidenechloride (1,1-dichloroethylene). The process of formation of the negative ions in charge inversion mass spectrometry is via near-resonant neutralization followed by spontaneous dissociation, and then endothermic negative ion formation. The intensity of the C2- peak relative to the C2H- peak in these spectra increased with decreasing ionization potential of the targets for both of the isomeric C2H2+ cations. The formation of the C2- anion is proposed to result from the dissociation of excited C2H2 neutrals into C2 and H2. The dependence on target species of the intensities of the C2- peak relative to the C2H- peak for HCCH and H2C=C: cannot be rationalized by the internal energy of the excited C2H2 neutrals. The differences indicate that the isomeric C2H2 neutrals dissociate into C2H and H prior to 1,2-hydrogen atom migration.
Influence of low-voltage discharge energy on the morphology of carbon nanostructures in induced benzene transformation
Bodrikov, Ivan Vasilievich,Ivanova, Anna Gennadevna,Serov, Anton Igorevich,Titov, Dmitry Yurievich,Titov, Evgeny Yurievich,Vasiliev, Alexander Leonidovich
, p. 39428 - 39437 (2021/12/24)
The directions of the transformation of benzene induced by low-voltage discharges at various energies of pulsed discharges were revealed. This paper shows the dependencies of the morphology and other characteristics of nanostructures obtained in the induced transformation of benzene on the energy of pulsed discharges. Nanostructures with different morphologies are formed when the energy of the low-voltage discharges changes during the induced transformation of benzene in the liquid phase. Two types of carbon nanostructures were formed in the induced destruction of benzene with a 90 μF capacitor. The first type of structure includes graphite fibers, two- and three-layer graphene sheets, as well as two- and three-layer hollow spheres and microstructures in the form of CNHs. The microstructures of the second type were onion-like spheroids. An increase in the capacitance up to 20?090 μF led to the formation of two types of nanostructures: onion-like spheroids and carbon fibers. A further increase in the capacitance to 40?090 μF caused the formation of onion-like spheroids.
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.
Reactors for Preparing Valuable Hydrocarbons and Hydrogen From Methane Through Non-Oxidative Pyrolysis
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Paragraph 0084-0091; 0099, (2021/10/11)
According to this disclosure, there is provided a pyrolysis reaction system and a direct non-oxidative methane coupling process using the same by which it is possible to reach the selectivity for good C≤10 hydrocarbons and at the same time to inhibit coke from being generated while a good methane conversion is maintained during direct conversion of methane into C2+ hydrocarbons through non-oxidative pyrolysis.
