Catalog of Infrared Spectra for Qualitative Analysis of Gases

Pierson, R. H.; Fletcher, A. N.; Gantz, E. St. Clair

doi:10.1021/ac60116a002

Cited by 296 publications

(70 citation statements)

References 14 publications

(3 reference statements)

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“…Purification, ~vhen required, was therefore done by orthodox means. The spectrum of fresh azomethane mas generally identical with the published datum (6); impurities, when present, turned out to be an assortment of the various chlorinated n~ethanes. * Azomethane containing any absorption a t or above 13 p (methyl chloride, n~ethylene chloride, chloroform) was discarded; azoinethane with traces of carbon tetrachloride (absorption a t 12.6 ,u) was purified b y distillation a t dry ice temperature.…”

Section: Azometha?zesupporting

confidence: 65%

The Thermal Decomposition of Azomethane: I. Effect of Added Olefin and Nitric Oxide

Forst¹,

Rice²

1963

Can. J. Chem.

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The addition of ethylene and propylene reduces the rate of azomethane decomposition as measured by the rate of nitrogen production, and also reduces the ratio CH4/N2 in the products, but the reduction in the value of both quantities is different for each of the two olefins. I n 10070 decomposition, ethylene and propylene both increase somewhat the ratio (nitrogen recovered)/(azomethane decomposed). These results are interpreted to mean that there is in fact a short chain in the pyrolysis, but that ethylene and propylene are unsuitable inhibitors.The addition of a few millimeters of NO reduces the rate t o a minimum which is lower than that with added propylene or ethylene (apparent chain length 2 to 3), but further addition of NO increases the rate again. Identical result is obtained in a packed vessel. The yield of methane, ethane, and ethylene is reduced t o almost zero with a sufficient amount of KO. The ratio (NO consumed)/(nitrogen produced) reaches the value of two in the neighborhood of the rate minimum. I t is concluded t h a t the net inhibited rate, i.e. rate corrected for the stimulatory effect of NO, refers to the initial unimolecular process C H~N Z C H ZThe rate a s well a s the activation energy of this process is found t o be pressure dependent.I t is shown by the use of the isotopic nitric oxide ISNO that about one-half of the rate increase a t higher NO pressures is due to nitrogen produced from NO. The remainder of the rate increase is accounted for by a NO-induced decomposition of azomethane.

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Section: Azometha?zesupporting

confidence: 65%

The Thermal Decomposition of Azomethane: I. Effect of Added Olefin and Nitric Oxide

Forst¹,

Rice²

1963

Can. J. Chem.

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“…[61] Chollet observed that the FVT of this material at 4008C/10 À3 hPa afforded a 15-20 % yield of 2-cyanopyrrole 31 as well as NO 2 as the only low molecular weight products (Scheme 10). [62] NO 2 was identified by its IR spectrum [63] in the gas-phase. Loss of NO 2 is not expected at such a low temperature under FVT conditions.…”

mentioning

confidence: 99%

Chemical Activation in Azide and Nitrene Chemistry: Methyl Azide, Phenyl Azide, Naphthyl Azides, Pyridyl Azides, Benzotriazoles, and Triazolopyridines

Wentrup¹

2013

Aust. J. Chem.

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Chemical activation (the formation of 'hot' molecules due to chemical reactions) is ubiquitous in flash vacuum thermolysis (FVT) reactions, and awareness of this phenomenon is indispensable when designing synthetically useful gas-phase reactions. Chemical activation is particularly prevalent in azide chemistry because the interesting singlet nitrenes are high-energy intermediates, and their reactions are highly exothermic. Consequently, chemical activation is observed in the isomerization of methylnitrene CH 3 N to methylenimine (methanimine) CH 2 ¼NH, facilitating the elimination of hydrogen to form HCN or HNC. Rearrangements of phenylnitrene, 1-and 2-naphthylnitrenes, and 2-, 3-and 4-pyridylnitrenes afford cyanocyclopentadiene, 3-and 2-cyanoindenes, and 2-and 3-cyanopyrroles, all showing the effects of chemical activation by undergoing facile interconversion of isomers. Chemical activation can often be reduced or removed entirely by increasing the pressure, thereby promoting collisional deactivation. Larger molecules having more degrees of freedom are better able to dissipate excess energy; therefore the effects of chemical activation are less pronounced or completely absent in the formation of 3-cyanoindole and 1-cyanobenzimidazoles from 3-and 4-quinolylnitrenes and 4-quinazolinylnitrenes, respectively. In compounds possessing nitro groups, chemical activation can cause the loss of the nitro group at nominal temperatures far below those normally needed to cleave the C-NO 2 bond.

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“…In this paper, we used a low resolution spectrum of Arvesen et al (1969) for the infrared solar radiation density for convenience, because according to the high resolution spectra obtained by the ATMOS (Atmospheric Trace Molecule Spectroscopy) instrument on the Spacelab 3 mission, the solar infrared spectrum between 2800 and 3200 cm −1 does not contain significant absorption features (Farmer and Norton, 1989). For the combination bands, we present only very rough band intensities (Table 1), which were derived by looking at a lab C 2 H 6 spectrum of Pierson et al (1956), since the quantitative values are not available in the literature.…”

Section: Band Modelsmentioning

confidence: 99%

Infrared excitation processes of C2H6 in comets

Kim

2014

Earth Planet Sp

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A time-dependent and line-by-line fluorescence model of the ν 7 band of C 2 H 6 has been constructed. Collisional (neutrals and electrons) and radiative excitation effects have been considered in the calculations of fluorescence efficiency factors (g-factors) of the C 2 H 6 ν 7 band. Since the lifetime of C 2 H 6 is ∼91,000 seconds at a heliocentric distance of 1 AU, C 2 H 6 molecules far from the nucleus approach fluorescence equilibrium, while molecules within the contact surface should have a much colder rotational distribution due to collisional equilibration with the low temperature gases in that region. We would recommend using "single-cycle" fluorescence models for the analysis of ν 7 band spectra taken with small apertures centered on the nucleus. We analyzed a ν 7 band spectrum of comet Hale-Bopp (C/1995 O1) obtained at the IRTF with the CSHELL on 2 March, 1997 (R = 1.1 AU, = 1.5 AU) using a square aperture of 1,000×2,000 km, and constructed synthetic spectra to compare with the observation. We analyzed spatial brightness profiles of the R Q 0 sub-branch and found that the eastward profile is very well matched by the models, but the observed westward profile is clearly broader than the eastward profile suggesting asymmetric outflow and/or extended sources. We derived a C 2 H 6 production rate of ∼1.7 ± 0.9 × 10 28 molec s −1 from the inner coma region of the comet at the time of the observation.

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Catalog of Infrared Spectra for Qualitative Analysis of Gases

Cited by 296 publications

References 14 publications

The Thermal Decomposition of Azomethane: I. Effect of Added Olefin and Nitric Oxide

The Thermal Decomposition of Azomethane: I. Effect of Added Olefin and Nitric Oxide

Chemical Activation in Azide and Nitrene Chemistry: Methyl Azide, Phenyl Azide, Naphthyl Azides, Pyridyl Azides, Benzotriazoles, and Triazolopyridines

Infrared excitation processes of C2H6 in comets

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