Über die Thermische Umsetzung von Mono‐n‐alkylbenzenen

Zychlinski, W.; Bach, G.; Zimmermann, G.; Sokolovskaja, V. G.; Shevel'kova, L. V.; Gusel’nikov, L. E.

doi:10.1002/prac.19873290511

Cited by 6 publications

(3 citation statements)

References 19 publications

(1 reference statement)

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“…The rate constant of propane homogeneous decomposition was measured experimentally by different experimental groups for the typical propane pressures to be in the range 0.1-1 bar. These experimental constants are in good concordance with the other [55][56][57][58][59][60][61]. The largest temperature range 1100-1400 K was covered by Benson [55] by the shock tube technique resulting in the first order rate constant expression:…”

Section: Co-pyrolysis Of C 3 H 8 +Fe(co) 5 Mixturessupporting

confidence: 81%

“…Our measurements of this rate constant were done for the inlet propane pressure 1.1 × 10 −3 bar, i.e. two orders of magnitude less than in the other authors' studies [55][56][57][58][59][60][61]. Thus, from the experimental data about propane decomposition, see figure 11(a), it is possible to infer the following first order rate constant: k C3H8 = 9.13 × 10 10 exp[−233.3(kJ mole −1 )/RT ] (s −1 ), (9) which is an order of magnitude less than Benson's value.…”

Section: Co-pyrolysis Of C 3 H 8 +Fe(co) 5 Mixturesmentioning

confidence: 99%

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Study of morphology of aerosol aggregates formed during co-pyrolysis of C₃H₈+ Fe(CO)₅

Иванова¹,

Onischuk²,

Stasio³

et al. 2007

J. Phys. D: Appl. Phys.

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Formation of aerosol nanoparticles as well as carbon nanotubes and nanofilaments is studied during co-pyrolysis of iron pentacarbonyl and propane with argon as a carrier gas in a flow reactor. Gaseous intermediates from propane thermal decomposition (CH4, C2H6 and C3H4) and Fe(CO)5 conversion are monitored by gas chromatography and IR-spectroscopy, respectively. The aerosol morphology is studied by transmission electron microscopy (TEM) and high resolution TEM. The aerosol particle concentration and size distribution are measured by an automated diffusion battery. The crystal phase composition of particles is studied by x-ray diffractometry. The decomposition of the Fe(CO)5 + Ar mixture resulted in an iron aggregate formation composed of fine primary particles. In the case of lower pyrolysis temperatures, about 450 K, the primary particle mean diameter is about 10 nm, and consequently, the majority of the primary particles are superparamagnetic, thus forming compact aggregates. At intermediate pyrolysis temperatures in the range 800–1040 K the primary particle diameter is about 20–30 nm, and most of the particles are ferromagnetic in nature. The coagulation of these particles results in a chain-like aggregate formation. Finally, at temperatures higher than the Curie point (1043 K) the ferromagnetic properties vanish and the formation of compact aggregates is observed again. The co-pyrolysis of Fe(CO)5 and C3H8 mixed with Ar carrier gas resulted in aerosol aggregate structures dramatically different from those formed by iron pentacarbonyl pyrolysis. In particular, in the temperature range 1070–1280 K, we observed Fe3C particles connected by long carbon nanotubes (CNTs). The aggregate morphology is described in terms of a fractal-like dimension Df, which is determined from TEM images on the basis of a scaling power law linking the aggregate mass (M) and radius (R), . The Fe3C–CNT aggregate morphology is a function of the inlet ratio between propane and iron pentacarbonyl concentrations [C3H8]0/[Fe(CO)5]0. At the low ratio of [C3H8]0/[Fe(CO)5]0 < 80 the fractal dimension of aggregates decreases (from 1.7 down to about 1) with the increasing ratio of inlet concentrations. This effect, as observed by TEM, is due to the increase in the mean nanotube length. Vice versa, in the range C3H8]0/[Fe(CO)5]0 > 80 the fractal aggregate dimension is higher for a larger ratio of [C3H8]0/[Fe(CO)5]0, which is explained by the larger thickness of growing nanotubes obtained for a relatively large propane concentration. The aggregate formation mechanism includes consecutive stages of iron aggregate formation due to Fe(CO)5 decomposition, carbon deposition on iron particles from C3H8 pyrolysis intermediates, carbon dissolution in iron particles, nanotube nucleation at the carbon concentration of about 60 at.% in Fe–C solution and disruption of the Fe–C aggregates into small pieces by the growing nanotubes.

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Section: Co-pyrolysis Of C 3 H 8 +Fe(co) 5 Mixturessupporting

confidence: 81%

Section: Co-pyrolysis Of C 3 H 8 +Fe(co) 5 Mixturesmentioning

confidence: 99%

Study of morphology of aerosol aggregates formed during co-pyrolysis of C₃H₈+ Fe(CO)₅

Иванова¹,

Onischuk²,

Stasio³

et al. 2007

J. Phys. D: Appl. Phys.

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“…The KIE, however, which is assumed to be independent of the hydrogen donor, scatters considerably (4.6-7.9). 281 -(£,"i,^')rh (17) 31.0…”

Section: Resultsmentioning

confidence: 99%

Relative reactivities of some carbon-hydrogen bonds in hydrogen abstraction by methyl radicals at 950 K

Kopinke¹,

Remmler²,

Mensing³

et al. 1994

J. Phys. Chem.

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Besonderheiten des Pyrolyseverhaltens von Isoalkylaromaten

Bach¹,

Ondruschka²,

Zychlinski³

et al. 1989

J. Prakt. Chem.

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Special Features in Pyrolysis Behaviour of Isoalkylaromatics The pyrolysis of cumene, sec. butyl‐ and tert. butylbenzene proceeds in a laboratory scale quartz vessel in the temperature range 600–750°C. Conversion occurs mainly via a radical‐chain mechanism in the side chain in proportions, determined by the dissociation energies of the CC‐ and CH‐bonds. Dealkylation was observed in greater amounts than for n‐alkylbenzenes. It is interpreted by H‐atom addition to the aromatic nucleus, followed by β‐scission to benzene and isoalkenes. It was be shown, that H‐atoms are formed by unusual reactions such as neophyl rearrangement and homolytic rupture of CC‐bonds in the side chain.

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Über die Thermische Umsetzung von Mono‐n‐alkylbenzenen

Cited by 6 publications

References 19 publications

Study of morphology of aerosol aggregates formed during co-pyrolysis of C₃H₈+ Fe(CO)₅

Study of morphology of aerosol aggregates formed during co-pyrolysis of C₃H₈+ Fe(CO)₅

Relative reactivities of some carbon-hydrogen bonds in hydrogen abstraction by methyl radicals at 950 K

Besonderheiten des Pyrolyseverhaltens von Isoalkylaromaten

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Über die Thermische Umsetzung von Mono‐n‐alkylbenzenen

Cited by 6 publications

References 19 publications

Study of morphology of aerosol aggregates formed during co-pyrolysis of C3H8+ Fe(CO)5

Study of morphology of aerosol aggregates formed during co-pyrolysis of C3H8+ Fe(CO)5

Relative reactivities of some carbon-hydrogen bonds in hydrogen abstraction by methyl radicals at 950 K

Besonderheiten des Pyrolyseverhaltens von Isoalkylaromaten

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Study of morphology of aerosol aggregates formed during co-pyrolysis of C₃H₈+ Fe(CO)₅

Study of morphology of aerosol aggregates formed during co-pyrolysis of C₃H₈+ Fe(CO)₅