23065-05-6

Upstream product

• 536-74-3 phenylacetylene 
• 2396-01-2 phenyl radical 
• 74-86-2 acetylene 
• 28143-79-5 1-phenyl vinyl triflate 

Downstream Products

• 17333-73-2 phenylium 
• 74-86-2 acetylene 
• 60665-78-3 Methylphenyl-p-anisylcarbenium-Ion 

Relevant academic research and scientific papers

Absolute rate constant for the reaction of phenyl radical with acetylene

The absolute rate constant for the reaction of phenyl radical with acetylene has been measured at 20 torr total pressure in the temperature range of 297 to 523 K using the cavity-ring-down technique. These new kinetic data could be quantitatively correlated with the data obtained earlier with a relative rate method under low-pressure (10-3-10-2 torr) and high-temperature (1000-1330 K) conditions. These kinetic data were analyzed in terms of the RRKM theory employing the thermochemical and molecular structure data computed with the BAC-MP4 technique. The calculated results reveal that the total rate constant for the C6H5+C2H2 reaction (kt) is pressure-independent, whereas those for the formation of C6H5C2H (kb) and the C6H5C2H2 adduct (kc) are strongly pressure-dependent. A least-squares analysis of the calculated values for 300-2000 K at the atmospheric pressure of N2 or Ar can be given by: kb = 9.5×10-42T9.33 exp(-1,713/T); kc = 1.8×10-7T-1.63 exp(-2,711/T); and kt = 4.1×10-18T1.77 exp(-1,152/T), all in units of cm3/s. The latter equation effectively represents the two sets of experimental data.

Gas-phase ion-molecule reaction of alpha-phenylvinyl cation towards substituted benzenes in the environment of an ITMS

Ion-molecule reactions between the α-phenylvinyl cation (α-PVC) and mono-substituted benzenes have been investigated using a quadrople ion-trap mass spectrometer. The α-PVC, generated by chemical ionization from phenylacetilene, was found to react selectively with mono-substituted benzenes bearing electron withdrawing groups to give the product ions [M + 103] + and the trans-vinylating product ions [M + 25]+. To characterize the reaction products, a combination of collision-induced dissociation, isotope-labeling experiments and model compounds were used. The results indicate, in addition to direct heteroatom alkylation, high extent of ortho attack. We attributed the positional selectivity of the α-PVC to the nature of the substituent on the neutral molecule. In particular, hydroxy and amino groups promoted the alkenylation at ortho position. Copyright

Lifetimes and UV-visible absorption spectra of benzyl, phenethyl, and cumyl carbocations and corresponding vinyl cations. A laser flash photolysis study

Benzyl (4-MeO, 4-Me, and 4-methoxy-1-naphthylmethyl), phenethyl (4- Me2N, 4-MeO, 3,4-(MeO)2, 4-Me, 3-Me, 4-F, 3-MeO, 2,6-Me2, parent, and 4- methoxy-1-naphthylethyl) and cumyl (4-Me2N, 4-MeO, 4-Me, parent) cations have been studied by laser flash photolysis (LFP) in 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP). In most cases styrene or α-methylstyrene precursors were employed for the phenethyl and cumyl ions, the intermediate being obtained by solvent protonation of the excited state. Benzyl cations were generated by photoheterolysis of trimethylammonium and chloride precursors. While a 4-MeO substituent provides sufficient stabilization to permit observation of cations in TFE, cations with less stabilizing substituents usually require the less nucleophilic HFIP. Even in this solvent, the parent benzyl cation is too short-lived (lifetime 6H4C+(R)-CH3 (R = Me, Et, i-Pr, t-Bu, cyclopropyl, C6H5, 4-MeOC6H4) were generated in TFE via the photoprotonation route. The alkyl series shows that steric effects are important in the decay reaction. The cation with R = cyclopropyl is a factor of 1.5 less reactive than the cation where R = phenyl. Several vinyl cations have also been generated by photoprotonation of phenylacetylenes. ArC+=CH2 has a reactivity very similar to that of its analog ArC+H-CH3, the vinyl cation being slightly (factors of 2-5) shorter-lived. For the various series of cations, including vinyl, substituents in the aryl ring have a consistent effect on the κ(max), a shift to higher wavelength relative to hydrogen of 15 nm for 4-Me, 30 nm for 4-MeO, and 50 nm for 4-Me2N.

Selectivity in the Reactions of Less Stable Carbocations with Magnesium Halides in Aprotic Solvents. A Theoretical Approach to the Constant Selectivity Principle.

The solvolysis of 7,7-bis(trifluoromethylsulfonyloxy)-2-norbornene (1a), 1-trifluoromethylsulfonyloxy-1-phenylethylene (2a), 2-methyl-1-cyclohexen-1-yl triflate (3a) and 4-camphenyl triflate (4a) in carbon disulfide or diethyl ether with added MgI2 and MgBr2 yields a mixture of the corresponding halides 5b-e, 6b-c, 7b-c and 8b-c.The ionization of the triflate group is favoured by coordination with the magnesium halide.The reaction with MgI2 was found to be second-order and is about 50 times more reactive than MgBr2.The selectivities of the intermediate cations 5-8 toward the nucleophiles MgI2 and MgBr2 are nearly constant, although the solvolysis rates differ by more than three powers of ten.A theoretical explanation of the constant selectivity principle is given.

Addition and Cyclization Reactions in the Thermal Conversion of Hydrocarbons with Enyne Structure, II. Analysis of Radicals and Carbenes from Ethynylbenzene

The pyrolysis of ethynylbenzene (1) in helium was studied in a tubular flow reactor at 10.7 mbar/1030 deg C and reaction times ranging from 5 to 30 ms.Reactive intermediates such as radicals and carbenes were scavenged with dimethyl disulfide (DMDS).Qualitative and quantitative analysis of the scavenging products and of the stable pyrolysis products were carried out by GC-MS analysis. - The radicals phenyl (2a), o-, m-, and p-ethynylphenyl (1c, d, e), 2- and 1-phenylvinyl (1a, b), 1- and 2-naphthyl (3a, b), methyl, hydrogen atoms, and radicals resulting from the addition of phenyl and ethynylphenyl radicals to the triple bond of ethynylbenzene were detected.Carbenes, such as phenylvinylidene, occur only in small traces and obviously play no role in the overall pyrolysis.Concentration profiles of the radicals and of some important pyrolysis products are presented and discussed.Based on the detected radicals, a reaction scheme for the pyrolysis of ethynylbenzene is proposed.Results of pyrolyses of mixtures of ethynylbenzene and ethyne show that naphthalene (3), acenaphthylene (12), and other compounds are produced by a sequence of ethyne addition and cyclization reactions. - Key Words: Ethynylbenzene, pyrolysis of / Scavenging of radicals / PAH formation