The Photolysis of the Aliphatic Aldehydes. XI. Acetaldehyde and Iodine Mixtures

Blacet, F. E.; Loeffler, D.

doi:10.1021/ja01256a045

Cited by 24 publications

(15 citation statements)

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“…By assuming that the nitrooxy enal has zero quantum yield above 347 nm and unity quantum yield below 347 nm, its photolysis frequency is 2.6 × 10 −4 s −1 for a solar zenith angle (SZA) of 45 • and 3.7 × 10 −4 s −1 for SZA of 0 • . It is worth mentioning that the condensed-phase and gas-phase absorption spectra should be different, because the solvent molecules affect the polarization and dipole moment of the solute (Bayliss and McRae, 1954;Braun et al, 1991;Linder and Abdulnur, 1971). Although we were unable to measure the gas-phase cross section of the nitrooxy enal, we could assess the uncertainty caused by using the condensed-phase spectrum in our calculation, by comparing the gas-phase and condensed-phase spectra of MACR and isopropyl nitrate (Fig.…”

Section: Photochemical Sinks Of the 41-isoprene Nitrooxy Enalmentioning

confidence: 99%

Photochemical degradation of isoprene-derived 4,1-nitrooxy enal

et al. 2016

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Abstract. In isoprene-impacted environments, carbonyl nitrates are produced from NO3-initiated isoprene oxidation, which constitutes a potentially important NOx reservoir. To better understand the fate of isoprene carbonyl nitrates, we synthesized a model compound, trans-2-methyl-4-nitrooxy-2-buten-1-al (4,1-isoprene carbonyl nitrate, or 4,1-isoprene nitrooxy enal), and investigated its photochemical degradation process. The measured OH and O3 oxidation rate constants (298 K) for this nitrooxy enal are 4.1(±0.7)  ×  10−11 cm3 molecules−1 s−1 and 4.4(±0.3)  ×  10−18 cm3 molecules−1 s−1, respectively. Its UV absorption spectrum was determined, and the result is consistent with TDDFT calculations. Based on its UV absorption cross section and photolysis frequency in a reaction chamber, we estimate that the ambient photolysis frequency for this compound is 3.1(±0.8)  ×  10−4 s−1 for a solar zenith angle of 45°. The fast photolysis rate and high reactivity toward OH lead to a lifetime of less than 1 h for the isoprene nitrooxy enal, with photolysis being a dominant daytime sink. The nitrate products derived from the OH oxidation and the photolysis of the nitrooxy enal were identified with an iodide-based chemical ionization mass spectrometer. For the OH oxidation reaction, we quantified the yields of two nitrate products, methyl vinyl ketone nitrate and ethanal nitrate, which together contributed to 36(±5) % of the first-generation products.

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Section: Photochemical Sinks Of the 41-isoprene Nitrooxy Enalmentioning

confidence: 99%

Photochemical degradation of isoprene-derived 4,1-nitrooxy enal

et al. 2016

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“…the most compelling evidence for reaction (la) being the fact that, at the lower wave-lengths, methane is still formed in the presence of iodine which was shown to remove all methyl radicals under the experimental conditions used (Gorin 1939;Blacet & Loeffler 1942).…”

Section: Is Of Acetaldehydet Diacetyl and Acetone 315mentioning

confidence: 98%

The photolysis of acetaldehyde, diacetyl and acetone at high intensity

Khan

Norrish

Porter

1953

Proc. R. Soc. Lond. A

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The photolysis of acetone, acetaldehyde and diacetyl have been investigated at absorbed intensities of the order 10 -3 Nhv cm -3 s -1 which are greater by a factor of about 10 7 than those normally used. Precautions were taken to keep the system nearly isothermal. Analysis of the products shows that, in this intensity region, reactions which are second order in radical concentration predominate, and no evidence was found of any reaction of radicals with the parent molecule. In the case of acetaldehyde this results in a complete change in the products, ethane formation being the main reaction of methyl, whilst in the photolysis of acetone and diacetyl only minor differences are observed. It has been possible to give a fairly complete account of all the analytical results and the intensity dependence of the product ratios in terms of reaction mechanisms which are logical extrapolations of the results of studies at low intensity. The simplifications resulting from the elimination of reactions with the parent molecule lead to information concerning the primary photochemical acts and those second-order radical reactions which are of minor importance at lower intensities.

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“…radicals; this interpretation is consistent with the observed products. If reaction [5] were the source of C H 7 0 \\re would expect some H-abstraction from aldehyde and a detectable yield of CHJ02H (the rate of [5] is proportional to [CH302]?) ; to expect this reaction to occur to the exclusion of [2], whose rate is proportional to [CH3O2][CH3C13O], seems unrealistic.…”

Section: Chain-initiat Ing Stepsmentioning

confidence: 99%

The Mechanism of the Photooxidation of Acetaldehyde at Room Temperature

Calvert¹,

Hanst²

1959

Can. J. Chem.

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The initial rates of product formation in the photooxidation of acetaldehyde a t room temperature have been determined through the use of infrared spectrometry. The rates of forrnation of the products peroxyacetic acid, carbon monoxide, carbon dioxide, methanol, formic acid, and acetic acid were determined in experiments with various pressures of acetaldehyde, oxygen, and added gases. The amounts of methylhydroperoxide and acetylperoxide formed in all of the experiments arere below the detection limit of the analytical methods. The results require that some modification and corrections be made to the mechanism suggested by McDowell and Sharples. INTRODUCTIONRecently 14cDowell and Sharples (1) published a series of kinetic studies of the photooxidation of acetaldehyde and propionaldehyde. The reactions were followed by the titration of the peroxyacid formed. Reported here is a study of the photooxidation of acetaldehyde in which a more detailed product analysis has been made through infrared absorption spectroscopy. The results show that the simple mechanism which McDowell and Sharples have inferred from their rate studies is very incomplete, and in some respects, it is incorrect. Soine suggested modifications and corrections to their mechanism are presented. E X P E R I M E N T A L Apparatus and MaterialsOur experiments were basically similar to those of McDowell and Sharples (1). We used comparable amounts of acetaldehyde in oxygen, and we photolyzed a t rooin temperature with light in the range 3000-3300 A. In order to accelerate the rates and facilitate the identification of the products of the chain-initiating and chain-tern~iilatii~g reactions, we used intensities about 1000 times those enlployed by ;\iIcDowell and Sharples.The acetaldehyde (Eastman-Kodak, white-label, fractionated a t reduced pressure), oxygen (Linde tank gas), and other added gases were mixed in a 10-cm Pyrex-body infrared absorption cell which was mounted in the sample beam of a Perkin-Elmer Model 21 double beam infrared spectrometer. The side of the cell was exposed to the radiation from a Pyrex-jacketed, water-cooled, high pressure mercury arc (AH-6) which was fastened about 10 inches from the cell. The absorption characteristics of the water jacket and the cell body limited the effective radiation t o the range 3000-3300 A. The inaxirnuin intensity of the light absorbed by the aldehyde was near 3100 A.T h e other reactant gases and standards for analysis were obtained as follows: tetramethylethylene was the research grade Phillips product; peroxyacetic acid and acetylperoxide were obtained from Becco and purified by distillation a t reduced pressure; ozone was prepared as needed by a simple ozonizer apparatus; the oxides of carbon were reagent gases of the Air Reduction Co.; inethailol was the Mallinckrodt Ailalytical 'Ma?zuscript received M a y g6, 1969.

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The Photolysis of the Aliphatic Aldehydes. XI. Acetaldehyde and Iodine Mixtures

Cited by 24 publications

References 0 publications

Photochemical degradation of isoprene-derived 4,1-nitrooxy enal

Photochemical degradation of isoprene-derived 4,1-nitrooxy enal

The photolysis of acetaldehyde, diacetyl and acetone at high intensity

The Mechanism of the Photooxidation of Acetaldehyde at Room Temperature

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