593-63-5Relevant academic research and scientific papers
Translational energy distributions of the products of the 193 and 157 nm photodissociation of chloroethylenes
Sato, Kei,Tsunashima, Shigeru,Takayanagi, Toshiyuki,Fujisawa, Ginji,Yokoyama, Atsushi
, p. 10123 - 10133 (1997)
The 193 and 157 nm photodissociations of three isomers of dichloroethylene (DCE) and trichloroethylene (TCE) were investigated using a technique of photofragmentation translational spectroscopy. The photofragmentation mechanisms were constructed by analyzing the time-of-flight spectra of C2H+2, Cl+, HCl+, C2HCl+, and C2Cl+2 produced by electron impact of neutral photofragments. In the 193 nm photodissociation, both the HCl elimination and the C-Cl bond rupture were important for all the compounds examined. It was concluded that secondary dissociation of the vibrationally excited chlorinated vinyl radical produced by the C-Cl bond rupture was important even at 193 nm. In the 157 nm photodissociation, the mechanisms were similar to those at 193 nm for cis-DCE, 1,1-DCE, and TCE, while only the C-Cl bond rupture occurred for trans-DCE. This result suggests that the 157 nm photodissociation of trans-DCE proceeds via the direct photodissociation following the photoexcitation to the repulsive 1nσ* state. A minor C-H bond rupture was also found in the 157 nm photodissociations of cis-DCE and TCE. On the basis of the present mechanisms, the translational energy distributions and the branching ratios were estimated for all the possible processes.
Photofragmentation of mono- and dichloroethylenes: Translational energy measurements of recoiling Cl and HCl fragments
Umemoto, Masayuki,Seki, Kanekazu,Shinohara, Hisanori,Nagashima, Umpei,Nishi, Nobuyuki,et al.
, p. 1657 - 1666 (1985)
Translational energy (Et) spectra of Cl and HCl fragments from vinylchloride, trans- dichloroethylene, cis-dichloroethylene, and 1,1'-dichloroethylene have been measured for the ?*t distribution and angular dependence of the Cl fragment indicate that the two-center dissociation occurs in a time faster than a rotation period and the recoiling organic radical (the counter fragment) is highly vibrationally excited.In dichloroethylenes, the presence of a second channel producing Cl atoms has been confirmed and attributed to the dissociation from the lower (n,?*) state through a (?,?*) state.The Et distribution of HCl fragments is nonstatistical and found to converge to null population at an energy less than half of the total available energy.This convergence point coincides with the value of the local available energy for the elimination reaction (activation energy -ΔHreaction0).The yield of HCl molecules relative to Cl atoms is estimated to be ca. 1.1 for vinylchloride.High efficiency of the HCl elimination is attributed to a rapid internal conversion from the (?,?*) state to the lowest (?,?*) state from which the pathway to the transition state for HCl elimination is opened in ground electronic manifolds.
Synthesis of (chlorovinyl)cobaloxime complexes, model complexes of proposed intermediates in the B12-catalyzed dehalogenation of chlorinated ethylenes
Rich, Autumn E.,DeGreeff, Angela D.,McNeill, Kristopher
, p. 234 - 235 (2002)
(Chlorovinyl)cobaloxime complexes, (dmgH)2(py)CoR (R = cis-dichlorovinyl, trans-2-chlorovinyl or 1-chlorovinyl, dmgH = dimethylglyoximate) were synthesized from the reaction of chlorinated ethylenes with in situ generated (dmgH)2Co(I) in the presence of pyridine.
Laser photolysis of trans-dichloroethylene at 193 nm: Quantum yields of photoproducts
Seki, Kanekazu,Kobayashi, Takanori,Ebata, Kazukiyo
, p. 200 - 203 (2011)
The photodissociation of trans-dichloroethylene (trans-DCE) was studied using an ArF excimer laser at 193 nm. Acetylene, chloroacetylene and hydrogen chloride are observed as products, but the chlorine molecule is not observed. The yields are determined to be 0.47 ± 0.10 and 0.35 ± 0.05 for acetylene and chloroacetylene, respectively. On the basis of the reaction mechanism, the sum of the quantum yields of hydrogen chloride molecules (Φ = 0.35) and chlorine atoms (Φ = 0.94) dissociated from trans-DCE is estimated to be greater than unity. These results indicate that two chlorine atoms are successively dissociated from the parent molecule by the photolysis at 193 nm.
The C-Cl bond fissions from the photolysis of CHClCCl2 at 193 nm
Lee, Yu-Jinn,Lee, Ya-Rong,Chou, Chih-Chiang,Lin, Shen-Maw
, p. 346 - 347 (1998)
The photolysis of CHClCCl2 at 193 nm was investigated by translational spectroscopy. Two distinct product translational distributions were derived for the C-Cl bond fissions. The internally excited C2HCl2 fragment from the main dissociation channel is shown to decompose totally to produce the Cl+C2HCl products.
Reductive transformation of trichloroethene by cobalamin: Reactivities of the intermediates acetylene, chloroacetylene, and the DCE isomers
Semadeni, Marco,Chiu, Pei-Chun,Reinhard, Martin
, p. 1207 - 1213 (1998)
The transformations of acetylene, chloroacetylene, 1,1-dichloroethene (DCE), and cis- and trans-DCE mediated by cobalamin in the presence of titanium(III) citrate were investigated at pH 8 and 22 °C. Acetylene quantitatively reacted to ethene via vinylcobalamin as the proposed intermediate. Chloroacetylene reacted to acetylene and vinyl chloride. Proposed intermediates are ethynylcobalamin and vinylcobalamin; respectively. The principal initial reaction of chloroacetylene formed ethynylcobalamin which decomposed to acetylene. The proposition for ethynyl- and vinylcobalamin formation is based on fitting reaction models to kinetic data. Kinetic modeling suggests half-lives for ethynyl- and vinylcobalamin of 1.4 and 251 h, respectively. 1,1-Dichloroethene reacted to approximately 20% volatiles (ethane, ethane, vinyl chloride, and acetylene) and 80% unidentified nonvolatile products. cis- and trans-DCE transformed slowly end produced small yields of vinyl chloride, ethene, and ethane. The transformations of acetylene, chloroacetylene, 1,1-dichloroethene (DCE), and cis- and trans-DCE mediated by cobalamin in the presence of titanium(III) citrate were investigated at pH 8 and 22 °C. Acetylene quantitatively reacted to ethene via vinylcobalamin as the proposed intermediate. Chloroacetylene reacted to acetylene and vinyl chloride. Proposed intermediates are ethynylcobalamin and vinylcobalamin, respectively. The principal initial reaction of chloroacetylene formed ethynylcobalamin which decomposed to acetylene. The proposition for ethynyl- and vinylcobalamin formation is based on fitting reaction models to kinetic data. Kinetic modeling suggests half-lives for ethynyl- and vinylcobalamin of 1.4 and 251 h, respectively. 1,1-Dichloroethene reacted to approximately 20% volatiles (ethene, ethane, vinyl chloride, and acetylene) and 80% unidentified nonvolatile products. cis- and trans-DCE transformed slowly and produced small yields of vinyl chloride, ethene, and ethane.
Distribution of Rotational States in Half-Collisions: 193-nm Photolysis of Dichloroethylene
He, Guo-xin,Yang, Yung-an,Huang, Yibo,Gordon, Robert J.
, p. 2186 - 2193 (1993)
The photodissociation of cis-, trans-, and 1,1-dichloroethylene (DCE) was studied by a pump-and-probe technique, using a 193-nm excimer laser to excite the parent molecule and time-of-flight resonance-enhanced multiphoton ionization to detect the products.We report here the nascent rotational state distributions of HCl(v''=0,1,2) and also the relative yields and intensity dependencies of HCl, H, Cl(2P3/2), Cl(2P1/2), HCl+, and Cl+.Our finding that the rotational state distributions of HCl for all three isomers are very similar leads us to conclude that the nascent distribution is determined far along the reaction coordinate and is insensitive to the isomeric for of the parent molecule, regardless of whether photoelimination results from a three- or four-center transition state.We also observed qualitatively different behavior for HCl(v''=0) and HCl(v''=1,2).As in our previous study of vinyl chloride, we found that HCl(v'>0) has a Boltzmann-like rotational state distribution, with temperatures in this case near 1400 K, whereas the distribution for v''=0 is described by a biexponential function with a low J'' temperature around 300 K and a high J'' temperature around 10000 K.We propose that the dichotomy between these two distributions is due to microscopic rather than chemical branching.The relative yields of HCl and Cl+ for trans-DCE are approximately double those of cis- and 1,1-DCE.This result is consistent with the interpretation that the yield-determining step is faster than cis-trans isomerization.The yields of all the other products are the same for cis and trans.For 1,1-DCE the yields of H, Cl(2P1/2), and HCl+ are much greater than for cis- and trans-DCE, while for Cl(2P3/2) the 1,1-DCE yield is somewhat smaller.The relative yields of H and Cl(2P3/2) can be explained by the stabilities of the organic fragments, while the HCl+ yields can be explained statistically.All of the neutral fragments were found to be produced by single-photon process, while HCl+ and Cl+ require three and four photons, respectively.Ladder climbing mechanisms are proposed for the two ionic framgents.
Shelf-Stable (E)- A nd (Z)-Vinyl-λ3-chlorane: A Stereospecific Hyper-vinylating Agent
Kanazawa, Junichiro,Miyamoto, Kazunori,Takagi, Taisei,Uchiyama, Masanobu,Watanabe, Yuichiro
supporting information, p. 3469 - 3473 (2020/04/30)
We report the first stereoselective synthesis of stable (E)- A nd (Z)-β-chlorovinyl-λ3-chlorane via direct mesitylation of 1,2-dichloroethylene with mesityldiazonium tetrakis(pentafluorophenyl)borate under mild reaction conditions. The structure of the (E)-vinyl-λ3-chlorane was established by single-crystal X-ray analysis. Because of the enormously high leaving group ability of the aryl-λ3-chloranyl group, vinyl-λ3-chloranes undergo not only SNVσ-type reaction with extremely weak nucleophiles such as perfluoroalkanesulfonate, iodobenzene, and aromatic hydrocarbons but also coupling with phenylcopper(I) species.
Metal ions do not play a direct role in the formation of carbon-carbon triple bonds during reduction of trihaloalkyls by CrII or V II
Levy, Ophir,Bino, Avi
supporting information, p. 15944 - 15947 (2013/02/23)
Carbyne radicals: Reactions of trihaloalkyl compounds with Cr2+ or V2+ in aqueous solutions yield alkynes and other products. Stepwise halogen abstractions from the trihaloalkyls form alkyl carbyne triradicals in solution. These radicals undergo coupling reactions, producing triply bonded alkyne molecules (see scheme). This process is not metal-assisted and does not occur in the coordination sphere of the metal ions.
GASEOUS DIELECTRICS WITH LOW GLOBAL WARMING POTENTIALS
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, (2010/12/31)
A dielectric gaseous compound which exhibits the following properties: a boiling point in the range between about ?20° C. to about ?273° C.; non-ozone depleting; a GWP less than about 22,200; chemical stability, as measured by a negative standard enthalpy of formation (dHf0); a toxicity level such that when the dielectric gas leaks, the effective diluted concentration does not exceed its PEL; and a dielectric strength greater than air.
