Acyl/aroylperoxyl radicals: a comparative study of the reactivity of peroxyl radicals resulting from the α-cleavage of ketones

El‐Agamey, Ali; McGarvey, David J.

doi:10.1039/b109309f

Cited by 14 publications

(18 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experimental parameters and the final results of the experiments are gathered in Tables III and IV • Mereau et al [2], Jagiella et al [3], Tomas et al [4], * liquid phase [43]. Lines: falloff curves for T = 297 K, dotted line: calculated with the parameters of [4], solid line: best fit for our data.…”

Section: Discussionmentioning

confidence: 89%

“…• The solid line is the best fit to our experimental data at room temperature: using the same value F C = 0.515 as in [4] and taking the value in liquid phase [43] The comparison of the two displayed falloff curves of Fig. 4 shows that our room temperature data cannot be conciliated with the predictions of [4] at 297 K. To account for our higher rate constants at 297 K as compared to [4], either the pre-exponential factor has to be multiplied by roughly a factor of 2 or the activation energy has to be downsized from 51.8 kJ mol −1 to 49 kJ mol −1 .…”

Section: Discussionmentioning

confidence: 95%

“…It is worth mentioning that a prompt decomposition was already observed in the reaction CH 3Ċ O + O 2 at low pressure [12]. Partial chemically activated decomposition would have a higher impact at lower temperature and thus decrease the apparent overall temperature [3], Tomas et al [4], * liquid phase [43]. Lines: falloff curves calculated for T = 347 (lower line) and 377 K (upper line) using the parameters of [4].…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Falloff curves for the unimolecular decomposition of two acyl radicals: RCO (+M) → R + CO (+M) by pulsed laser photolysis coupled to time‐resolved infrared diode laser absorption

Dusanter

Elmaimouni

Fittschen

et al. 2005

Int J of Chemical Kinetics

View full text Add to dashboard Cite

The rate constants k d for the unimolecular decomposition of two acyl (RĊO) radicals: 2,2-dimethylpropionyl (CH 3 ) 3 CĊO and 2-methylpropionyl (CH 3 ) 2 CHĊO (pivaloyl and isobutyryl, respectively in what follows) have been directly measured via the time-resolved kinetics of CO formation as a function of pressure and temperature. The acyl radicals are generated by H-atom abstraction of the aldehydic hydrogen from the corresponding substituted propanals using pulsed laser photolysis of aldehyde/Cl 2 /N 2 mixtures. The buildup of CO concentration is monitored by time-resolved infrared absorption at ∼ =2177 cm −1 . The extent of the chain reactions triggered by the reactions of Cl 2 with alkyl and acyl radicals (thus generating further Cl atoms after the initial laser pulse) has been limited by adding variable known concentrations of O 2 , a radical scavenger which is sequestering all radicals to form less reactive RO 2 radicals. Besides k d , we have also determined for the first time the rate constants of the reactions of the two acyl radicals with O 2 ; since the latter do not exhibit any clear trend with either temperature or pressure, we thus adopt the average of all experimental values: i.e. for pivaloyl : k O 2 = (3.5 ± 1.0) × 10 −12 cm 3 molecule −1 s −1 , and for isobutyryl : k O 2 = (3.2 ± 1.0) × 10 −12 cm 3 molecule −1 s −1 . Our values of k d , which are in the falloff range, are compared to those obtained from theoretical calculations using the Troe formalism [5]. For pivaloyl at 298 K, we obtain the following limiting rate constants : k 0 = 2.1 × 10 −13 cm 3 molecule −1 s −1 , k ∞ = 4.3 × 10 5 s −1 , F C = 0.515, which are at variance with the theoretical predictions of Tomas et al. (Phys Chem Chem Phys 2000, 2, 1165-1174

show abstract

Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Falloff curves for the unimolecular decomposition of two acyl radicals: RCO (+M) → R + CO (+M) by pulsed laser photolysis coupled to time‐resolved infrared diode laser absorption

Dusanter

Elmaimouni

Fittschen

et al. 2005

Int J of Chemical Kinetics

View full text Add to dashboard Cite

show abstract

“…undergoes -cleavage to form acetyl and diphenylmethyl radicals, which react rapidly with oxygen to form ACP  and diphenylmethylperoxyl radical (Scheme 3) [27]. Also, ACP  is principally responsible for the reactions with carotenoids observed on the timescales studied due to the reactivity difference between the resulting peroxyl radicals i.e.…”

Section: Methodsmentioning

confidence: 99%

“…Also, ACP  is principally responsible for the reactions with carotenoids observed on the timescales studied due to the reactivity difference between the resulting peroxyl radicals i.e. ACP  is much more reactive than diphenylmethylperoxyl radical [27]. Table 1.…”

Section: Methodsmentioning

confidence: 99%

Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor

El‐Agamey

McGarvey

2016

Free Radical Biology and Medicine

Self Cite

View full text Add to dashboard Cite

Cite this article as: Ali El-Agamey and David J. Mcgarvey, Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor, Free Radical Biology and Medicine, http://dx.doi.org/10.1016/j.freeradbiomed. 2015.10.427 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe reactions of acetylperoxyl radicals with different carotenoids (7,7'-dihydro-β-carotene and ζ-carotene) in SDS and CTAC microemulsions of different compositions were investigated using laser flash photolysis (LFP) coupled with kinetic absorption spectroscopy. The primary objective of this study was to explore the influence of microemulsion composition and the type of surfactant used on the yields and kinetics of various transients formed from the reaction of acetylperoxyl radicals with carotenoids. Also, the influence of the site (hydrocarbon phases or aqueous phase) of generation of the peroxyl radical precursor was examined by using 4-acetyl-4-phenylpiperidine hydrochloride

show abstract

Thiol−Ene Coupling in a Continuous Photo‐Flow Regime

Janssens¹,

Debrouwer²,

Aken³

et al. 2018

ChemPhotoChem

View full text Add to dashboard Cite

Photoinitiated thiol−ene chemistry is a promising technique for use in chemical synthesis and related sciences. In view of scaling, the process was successfully transferred to a continuous flow regime with compelling results in terms of selectivity, efficiency, and productivity. A series of selected thiols and enes were reacted using 2,2‐dimethoxy‐2‐phenylacetophenone as radical initiator to respond to the 365 nm UV‐LED source. Process parameters were evaluated and chemical cross‐reactivity of the different substrates was assessed. Optimization of conditions gave high productivity of the thio‐ether resulting from the model reaction between benzyl thiol and 1‐decene when performed under neat conditions. The robustness of this method was demonstrated by running it under continuous operation for an extended period of time, with product output reaching constant yields of 90–92 % as soon as the steady‐state regime was installed. The corresponding space–time yield was 9.75 kg l−1 h−1, an impressive value that further demonstrates scale‐up potential.

show abstract

Acyl/aroylperoxyl radicals: a comparative study of the reactivity of peroxyl radicals resulting from the α-cleavage of ketones

Cited by 14 publications

References 49 publications

Falloff curves for the unimolecular decomposition of two acyl radicals: RCO (+M) → R + CO (+M) by pulsed laser photolysis coupled to time‐resolved infrared diode laser absorption

Falloff curves for the unimolecular decomposition of two acyl radicals: RCO (+M) → R + CO (+M) by pulsed laser photolysis coupled to time‐resolved infrared diode laser absorption

Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor

Thiol−Ene Coupling in a Continuous Photo‐Flow Regime

Contact Info

Product

Resources

About