Pyrolysis of acrylonitrile at elevated temperatures: studies with a single-plus shock tube

Lifshitz, Assa; Bidani, Menashe; Suslensky, Aya; Tamburu, Carmen

doi:10.1021/j100341a038

Cited by 17 publications

(9 citation statements)

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“…Yet the production of molecular hydrogen and the counterpart cyanoallene should be present as well. 6 These compounds appear only at high temperature and in trace quantities, which is in accordance with the mole fraction profile of C 4 H 3 N. Benzene is a minor product at high temperature. The C 3 H 3 radical, which is mainly produced by an abstraction of a hydrogen atom from both allene and propyne, can dimerize for the formation of benzene.…”

Section: Mole Fraction Profiles Of Other Pyrolysis Productssupporting

confidence: 74%

“…Pyrrole as a representative of pyrrolic compound, together with its isomers , and derivatives, − has been studied in the pyrolysis investigation. − The pyrolysis of pyrrole was studied behind reflected shocks in a pressurized driver single-pulse shock tube with gas chromatograph by Lifshitz et al At low temperature range, the isomers of pyrrole (allyl cyanide and cis -/ trans -crotononitrile) were the principal products, together with hydrogen cyanide (HCN) and propyne/allene. At elevated temperatures, acetylene, acetonitrile, cyanoacetylene, and hydrogen became major products.…”

Section: Introductionmentioning

confidence: 99%

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An Experimental and Theoretical Study of Pyrrole Pyrolysis with Tunable Synchrotron VUV Photoionization and Molecular-Beam Mass Spectrometry

Hong

Zhang

et al. 2009

J. Phys. Chem. A

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The pyrolysis of pyrrole (6.46% pyrrole in argon) has been performed with the tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry (MBMS) technique. The experiment was carried out over the temperature range of 1260-1710 K at a pressure of 267 Pa. About 30 intermediates have been identified by near-threshold measurements of photoionization mass spectra, and the corresponding mole fractions versus temperatures have been obtained. Moreover, the isomers of some pyrolysis products have been identified by the measurement of photoionization efficiency spectrum. The major products are H(2), C(2)H(2), HCN, C(3)H(4) (propyne), and C(2)H(3)N (acetonitrile). Meanwhile, some new intermediates, such as C(4)H(4)N (cyanoallyl radical) and C(2)H(2)N (cyanomethyl radical), have been determined. The major pyrolysis channels have been provided with the high-level ab initio G3B3 calculation and are well consistent with the experimental observation. The formation pathway of HCN via the cyclic carbene tautomer has been proved to be the lowest formation pathway, which is in accordance with previous theoretical work. The potential pathways of the early formed C(4)H(4)N species together with their subsequent consumption to C(2)H(2)N and C(2)H(2) have been discussed in detail. Also, the formation pathways of the major products of C(2)H(3)N and C(2)H(2) have been investigated as well.

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Section: Mole Fraction Profiles Of Other Pyrolysis Productssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

An Experimental and Theoretical Study of Pyrrole Pyrolysis with Tunable Synchrotron VUV Photoionization and Molecular-Beam Mass Spectrometry

Hong

Zhang

et al. 2009

J. Phys. Chem. A

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“…The same behavior has been reported and simulated by Lazare et al [30]. Due to the high absorption coefficient of the styrene monomer at 266 nm [31], the styrene units in the copolymer backbone produce a synergetic effect enhancing absorption and generating heat, allowing in this manner the decomposition of acrylonitrile units and thus producing bubbles [32]. A more quantitative assessment of the degree of hole formation can be made by image analysis of the SEM micrographs.…”

Section: Resultssupporting

confidence: 72%

Rapid Fabrication of Periodic Patterns on Poly(styrene-co-acrylonitrile) Surfaces Using Direct Laser Interference Patterning

Broglia

Acevedo

Langheinrich

et al. 2015

International Journal of Polymer Science

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Periodic microstructures in styrene-acrylonitrile (SAN) copolymers are fabricated by two-beam direct laser interference patterning using a nanosecond pulsed laser operating at a wavelength of 266 nm. The SAN copolymers are synthesized using different molar ratios (styrene to acrylonitrile) by a free radical polymerization process. The chemical composition of the copolymers and their properties are determined using Fourier transformed infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Depending on the composition of the irradiated copolymer films, with weight ratios ranging from 58 to 96.5% of styrene to acrylonitrile, different ablation behaviors are observed. The laser fluence necessary to locally ablate the copolymer is found to be dependent on the copolymer composition. Unlike other dielectric polymers, the laser irradiation produced both direct ablation of the irradiated material and collapse of the surface. It is shown that, by varying the laser fluence and the copolymer composition, the surface structure can be changed from a periodic pattern with a swelled topography to an ablated-like structure. The number of holes does not depend monotonically on the amount of PS or PAN units but shows a more complex behavior which depends on the copolymer composition and the laser fluence.

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“…Pyrrole and pyridine are ideal model compounds for studying the complex chemical reactions that occur when heavy fuels undergo pyrolysis and combustion. Thermal decomposition of pyrrole and pyridine has been the subject of many detailed experimental − and theoretical − investigations. It was reported that in the temperature range of 600−650 °C, the major products of pyridine decomposition are atomic hydrogen and 2,2‘-bipyridine .…”

Section: Introductionmentioning

confidence: 99%

A Theoretical Investigation of the Decomposition Mechanism of Pyridyl Radicals

et al. 2000

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We carried out a detailed quantum mechanical study of the unimolecular decomposition mechanism of pyridine. The critical structures of all reasonable reaction pathways were optimized by density functional theory using the B3LYP functional and 6-31G** basis set. Relative energies were evaluated based on single-point QCISD-(T)/cc-pVDZ energies. In agreement with general belief and pervious theoretical studies, the calculated results indicate that C-H bond scission in pyridine preferentially produces the o-pyridyl radical. Also in agreement with the accepted mechanism, the calculations indicate that ring-opening via C-N bond cleavage in o-pyridyl radical is more favorable than C-C bond cleavage, as the former has a significantly lower activation barrier and the resulting open-chain cyano radical is more stable than other linear C 5 NH 4 radicals. The calculated activation energy for the formation of cyanovinylacetylene + H from the open-chain cyano radical is the lowest, compared to the other channels considered. However, activation entropy favors C-C bond cleavage producing acetylene and cyanovinyl radical instead of cyanovinylacetylene and atomic hydrogen. On the basis of the calculated activation energies and activation entropies, transition state theory predicts that, in the temperature range of 1300-1800 K, the formation of acetylene + cyanovinyl radical from o-pyridyl radical is two to three times the rate of formation of cyanovinylacetylene + H. The calculations indicate that direct C-H bond scission from all three pyridyl radicals producing 2,3-and 3,4-pyridynes is also a favorable channel from energy consideration.

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Pyrolysis of acrylonitrile at elevated temperatures: studies with a single-plus shock tube

Cited by 17 publications

References 0 publications

An Experimental and Theoretical Study of Pyrrole Pyrolysis with Tunable Synchrotron VUV Photoionization and Molecular-Beam Mass Spectrometry

An Experimental and Theoretical Study of Pyrrole Pyrolysis with Tunable Synchrotron VUV Photoionization and Molecular-Beam Mass Spectrometry

Rapid Fabrication of Periodic Patterns on Poly(styrene-co-acrylonitrile) Surfaces Using Direct Laser Interference Patterning

A Theoretical Investigation of the Decomposition Mechanism of Pyridyl Radicals

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