3161-99-7

Upstream product

• 460-12-8 Butadiyne 
• 74-85-1 ethene 
• 593-61-3 bromoethyne 
• 624-92-0 Dimethyldisulphide 
• 74-86-2 acetylene 
• 89-32-7 Pyromellitic dianhydride 
• 536-74-3 phenylacetylene 
• 7440-44-0 pyrographite 
• 75-05-8 acetonitrile 
• 71-43-2 benzene 
• 1070-71-9 cyanoacetylene cation radical 
• 460-12-8 diacetylene cation 

Downstream Products

• 74-86-2 acetylene 

Relevant academic research and scientific papers

UV laser photodeposition of nanomagnetic soot from gaseous benzene and acetonitrile-benzene mixture

Megawatt KrF laser gas-phase photolysis of benzene and acetonitrile-benzene mixture was studied by using mass spectroscopy-gas-chromatography and Fourier transform infrared spectroscopy for analyses of volatile products, and by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, electron microscopy and magnetization measurements for analyses of solid products deposited from the gas-phase. The results are consistent with carbonization of benzene and decomposition of non-absorbing acetonitrile in carbonizing benzene through collisions with excited benzene and/or its fragments. The solid products from benzene and acetonitrile-benzene mixture have large surface area and are characterized as nanomagnetic amorphous carbonaceous soot containing unsaturated C centers prone to oxidation. The nanosoot from acetonitrile-benzene mixture incorporates CN groups, confirms reactions of benzene fragments with CN radical and has a potential for modification by reactions at the CN bonds.

Submerged electric arc between graphite electrodes: A one-pot tool for the synthesis of long-chain polyynes in solution

Polyynes, a class of molecules described by the general formula H-(CC) mH (where m is an integer) can be synthesized using an electric arc between graphite electrodes submerged in an organic solvent such as methanol, n-hexane, n-dodecane, decahydronaphthalene or acetonitrile. When the electric arc is used in acetonitrile at -40°C, polyyne chains of up to 18 carbon atoms (m=9) have been produced together with monocyanopolyyne as by-product. The polyynes can be reduced to ene-ynes by shaking a hexane solution of them with Zn/HCl.

A detailed numerical study of the evolution of soot particle size distributions in laminar premixed flames

In this work, two numerical techniques, viz. the method of moments and a discrete h-p-Galerkin method, have been applied for numerical simulation of soot formation in a laminar premixed acetylene/oxygen/argon flame. From the evolution of the PAH and the soot particle size distributions, new insight into the different processes of soot formation is provided. For this, the single submodels have been examined with respect to their influence on the PAH and the soot particle size distributions. The particle inception step was studied in detail by comparing the simulated PAH size distributions with experimental results. Additionally, an estimation of the interaction energy of layered PAH dimers was performed by quantum chemical calculations. From these results, some evidence for the particle inception model employing coalescence of PAH molecules has been found. The numerical results for the gas phase chemical species, the particle number densities and volume fractions of soot as well as for the soot particle size distributions are compared with experimental data. Thereby, the consistency of the entire model is demonstrated.

The ultraviolet photochemistry of phenylacetylene and the enthalpy of formation of 1,3,5-hexatriyne

The ultraviolet photochemistry of phenylacetylene was studied in a molecular beam at 193 nm. The only primary photofragments observed were HCCH (acetylene) and C6H4. Some of the C6H4 molecules were found to decompose to 1,3,5-hexatriyne and molecular hydrogen. An enthalpy of formation of ΔHf ≤ 160 ± 4 kcal mol-1 was determined for 1,3,5=hexatriyne from the energetic threshold for this process. This experimentally determined value agrees well with our ab initio calculations performed at the G2 level of theory. Angular distribution measurements for the HCCH + C6H4 channel yielded an i sotropic distribution and were attributed to a long-lived intermediate and ground-state dissociation. An exhaustive search yielded no evidence for the phenyl + ethynyl or, the atomic hydrogen elimination channels even though these were observed in the pyrolytic studies of phenylacetylene.

Scavenging of hydrocarbon radicals from flames with dimethyl-bisulfide II. Hydrocarbon radicals in fuel-rich low-pressure flames of acetylene, ethylene, 1,3-butadiene and methane with oxygen

The new technique of free-jet condensation/scavenging with dimethyl-disulfide has been applied for the quantitative analysis of hydrocarbon radicals and carbenes in flat premixed hydrocarbon/oxygen flames burning with fuel-rich mixtures at 27 mbar. The results are reported as profiles of mole fractions of the radicals. The limit of detectability was about l-10~7mole fraction. Qualitatively the radicals are very similar with the four fuels, but there are large differences in their quantities. While in the methane flame only C1 and C2 radicals were present in detectable concentration, higher radicals up to naphthyl could be detected with the unsaturated fuels. Although methyl could not be determined quantitatively, it was found to be the major hydrocarbon radical in all flames. Methoxy radical was only found in the methane flame. Whereas, for example, C2, C3H2 and C3H are typical high-temperature species, C2H is surprisingly formed at the beginning of the oxidation zone at relatively low temperature. Vinyl and the vinyl-type radicals C2nH3 (n = I to 4) are in equilibrium with acetylene and the polyynes (C2nH2) at maximum flame temperature and in the burned gas. Since phenyl peaks always after benzene, it is concluded that it is mainly a degradation product from benzene and other lower aromatics. The mechanism of formation of C2H and C2, the equilibria of the C2nH3 and the relation between aliphatic and aromatic radicals are discussed. VCH Verlagsgesellschaft mbH, 1997.

Photolysis of 1,2,4,5-Benzenetetracarboxylic Dianhydride in a Low-Temperature Argon Matrix. Direct Observation of Reactive Intermediates Stepwise Produced

Irradiation of 1,2,4,5-benzenetetracarboxylic dianhydride produced stepwise a cyclopropenone and benzyne intermediates with the release of CO2 and CO in a low-temperature argon matrix.In the final stage the further extrusion of CO2 and CO gave 1,3,5-hexatriyne which was a potential product in the ring-opening reaction of benzdiyne.

The high-resolution infrared spectrum of diacetylene and structures of diacetylene, triacetylene and dicyanoacetylene

The ν6 and ν8 combination band of diacetylene has been remeasured at 0.0019 cm-1 resolution with a Fourier transform infrared spectrometer.Analysis and assignment of the improved data sets were carried out with an interactive Loomis-Wood fitting program.Altogether more than 1400 assignments were made and band origins, rotational and distortion constants for the main band and associated hot bands were determined.The band centre was found to be 1241.060828(37) cm-1 and the ground-state rotational and distortion constants, B0 and D0, were found to be 0.14641021(52) cm-1 and 1.6085(49)*10-8 cm-1, respectively.The experimental values of B0 for diacetylene, triacetylene and dicyanoacetylene are compared with values predicted from ab initio calculations, and with values obtained from estimates derived from the known structural parameters of HC3N and HC5N.Several very weak difference bands, 110901, 110801 and 410601, and combination bands, 510610 and 110910 in the region 3600-2600 cm-1 were also assigned.

Reactions of Ethynyl Radicals with Alkynes in the System Sodium Vapour/Ethynylbromide/Alkyne

The radicals were generated from the respective halide RX by the reaction Na + RX -> R + NaX in a low-pressure flow reactor fed by a multi-slit diffusion burner.Test results are reported for the system Na/CH3I giving k(Na + CH3I) = 6.0E13 and k(CH3 + CH3) = 2.8E13 cm3 mol-1 s-1.The main part deals with the production of C2H in the system Na/C2HBr and its consecutive reactions with C2HBr and added C2H2 and C4H2.The rate constant k(Na + C2HBr) was found to be 2.9E13 cm3 mol-1 s-1.The bimolecular rate constants of C2H with the compounds above have been determined to 1.0E14, 2.3E13 and 4.0E13 cm3 mol-1 s-1, respectively, at a temperature of 603 K. - The main products in this reaction system are polyynes with a minor formation of ethyne and very little hydrogenated polyynes.The formation of an aromatic compound (ethynylbenzene) is negligibly small, a fact which is discussed in its relation to aromates in hydrocarbon flames.The primary reacion Na + C2HBr and its products are discussed as well as the unimolecular decomposition and stabilization of energized adducts formed by C2H. - Chemical Kinetics / Elementary Reactions / Flames / Radicals

SCAVENGING OF RADICALS FROM THE GAS PHASE BY FREEZING WITH DIMETHYL DISULFIDE: 2. RADICALS FROM DISCHARGES AND A FLAME OF ACETYLENE.

The method of detecting radicals from low-pressure gas-phase systems by scavenging with dimethyl disulfide (DMD) has been applied to microwave discharges in C//2H//2/He mixtures and to a C//2H//2/O//2 flame. It was accomplished by condensing a supersonic nozzle beam from the reaction system together with a beam of DMD on a liquid-N//2 cooled surface. The scavenging products were measured by GC/MS after warming-up. Radicals measured in the discharge were C//2H, C//4H, C//6H, C//3H//2, C//2 besides H atoms. Preliminary measurements on the flame showed that C//6H//5 (phenyl), CH//2, C//3H//2, besides H and O atoms were prominent radicals at the end of the oxidation zone. The concentration of phenyl is of the same order as that of e. g. naphthalene.

ANALYSE PAR SPECTROMETRIE DE MASSE DE LA STRUCTURE D'UNE FLAMME DE DIFFUSION C2H2/O2/AR

Neutral species present in C2H2/O2/Ar diffusion flame stabilized under reduced pressure (30 torrs) have been analysed by a molecular beam mass spectrometer system in order to specify the mechanism of soot formation.Comparison of the mole fraction profiles of polyacetylenic hydrocarbons and polycyclic aromatic hydrocarbons (P.A.H.) shows that the latters are considerably more reactive than the formers and hence appear as soot precursors.It was worth considering the nature of the intermediate species in the overall machanisms leading to the formation of the first aromatic rings or to an increase in the number of aromatic rings : C2H2 -> C6H6 -> H.A.P.Result suggest that C4 hydrocarbons, in particular C4H4, play an important role in these stages.