Reaction of benzene radical cation with water. Evidence for the reversibility of hydroxyl radical addition to benzene

Eberhardt, Manfred K.

doi:10.1021/ja00403a042

Cited by 47 publications

(30 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…C std is the amount fraction of benzene in the gas cylinder. (Eberhardt, 1981). This effect is in line with the quenching effect of water vapour as both of them reduce the amount of ionised benzene reaching the electrodes.…”

Section: Influence Of Humidity On Benzene Measurementssupporting

confidence: 68%

“…Its harmful health effects have been studied during the last 5 decades (Bahadar et al, 2014;Gist and Burg, 1997;Haley, 1977;Smith, 2010). Evidence for an association with childhood leukaemia (D'Andrea and Reddy, 2016a) and alterations in hematologic and liver profiles in adults (D'Andrea and Reddy, 2016b) is lately growing. The major source of benzene in cities is gasoline, as it is one of its components as well as a product of its combustion (von Schneidemesser et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

et al. 2017

View full text Add to dashboard Cite

Abstract. Calibration of in situ analysers of air pollutants is usually done with dry standards. In this paper, the influence of sample temperature and environmental humidity on benzene measurements by gas chromatography coupled with a photoionisation detector (GC-PID) is studied. Two reference gas mixtures (40 and 5 µg m −3 nominal concentration benzene in air) were subjected to two temperature cycles (20/5/20 • C and 20/35/20 • C) and measured with two identical GC-PIDs. The change in sample temperature did not produce any significant change in readings. Regarding ambient humidity, the chromatographs were calibrated for benzene with dry gases and subjected to measure reference standards with humidity (20 and 80 % at 20 • C). When measuring a concentration of 0.5 µg m −3 benzene in air, the levels of humidity tested did not produce any significant interference in measurements taken with any of the analysers. However, when measuring a concentration of 40 µg m −3 , biases in measurements of 18 and 21 % for each respective analyser were obtained when the relative humidity of the sample was 80 % at 20 • C. Further tests were carried out to study the nature of this interference. Results show that humidity interference depends on both the amount fractions of water vapour and benzene. If benzene concentrations in an area are close to its annual limit value (5 µg m −3 ), biases of 2.2 % can be expected when the absolute humidity is 8.6 g cm −3 -corresponding to a relative humidity of 50 % at 20 • C. This can be accounted for in the uncertainty budget of measurements with no need for corrections. If benzene concentrations are above the annual limit value, biases become higher. Thus, in these cases, actions should be taken to reduce the humidity interference, as an underestimation of benzene concentrations may cause a mismanagement of air quality in these situations.

show abstract

Section: Influence Of Humidity On Benzene Measurementssupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

et al. 2017

View full text Add to dashboard Cite

show abstract

“…As pointed out above, the reaction of OH radical with similar structures such as aniline shows a predominance of the addition/elimination reaction over the abstraction reaction from the NH 2 group. 11,25,26 Thus, for OH attack on guanine from both our and other theoretical treatments 10,13 and experiments on similar structures, it would appear that addition/elimination should be a very competitive route with direct H-atom abstraction. Further, G(N 1 -H) • and G(N 2 -H) • can be products of both addition/elimination and abstraction which makes the distinction of the pathways of formation of G(N 1 -H) and G(N 2 -H) radicals quite difficult unless the C 4 /C 5 adducts or ion-pair species are observed by experiments at short times.…”

Section: Discussionmentioning

confidence: 61%

“…11,25 The addition reaction of OH radical with benzene, idobenzenes and other aromatic organics in aqueous solutions show the formation of radical cation through water elimination. 26 These previous results strongly suggest that for OH • attack on guanine both abstraction and addition elimination mechanisms are in effect.…”

Section: Resultsmentioning

confidence: 84%

Hydroxyl Radical (OH^•) Reaction with Guanine in an Aqueous Environment: A DFT Study

2011

View full text Add to dashboard Cite

The reaction of hydroxyl radical (OH•) with DNA accounts for about half of radiation-induced DNA damage in living systems. Previous literature reports point out that the reaction of OH• with DNA proceeds mainly through the addition of OH• to the C=C bond of the DNA bases. However, recently it has been reported that the principal reaction of OH• with dGuo (deoxyguanosine) is the direct hydrogen atom abstraction from its exocyclic amine group rather than addition of OH• to the C=C bond. In the present work, these two reaction pathways of OH• attack on guanine (G) in the presence of water molecules (aqueous environment) are investigated using the density functional theory (DFT) B3LYP method with 6-31G* and 6-31++G** basis sets. The calculations show that the initial addition of the OH• at C4=C5 double bond of guanine is barrier free and the adduct radical (G-OH•) has only a small activation barrier of ca. 1 – 6 kcal/mol leading to the formation of a metastable ion-pair intermediate (G•+---OH−). The formation of ion-pair is a result of the highly oxidizing nature of the OH• in aqueous media. The resulting ion-pair (G•+---OH−) deprotonates to form H2O and neutral G radicals favoring G(N1-H)• with an activation barrier of ca. 5 kcal/mol. The overall process from the G(C4)-OH• (adduct) to G(N1-H)• and water is found to be exothermic in nature by more than 13 kcal/mol. (G-OH•), (G•+---OH−), and G(N1-H)• were further characterized by the CAM-B3LYP calculations of their UV-visible spectra and good agreement between theory and experiment is achieved. Our calculations for the direct hydrogen abstraction pathway from N1 and N2 sites of guanine by the OH• show that this is also a competitive route to produce G(N2-H)•, G(N1-H)• and H2O.

show abstract

“…The sulfate radical is well known to be able to capture one electron from a suitable aryl substrate to form an aryl cation radical [19][20][21]. A one-electron transfer from a phenyl ring of the trityl moiety to 2 may form an aryl cation radical intermediate, which then undergoes a cleavage reaction of the C-O bond of the 5Ј-O ether to form the product 3.…”

Section: Resultsmentioning

confidence: 99%

Facile selective detritylation of 5?-primary alcohols of pyrimidine nucleosides using tetra-n-butylammonium peroxydisulfate

1997

View full text Add to dashboard Cite

Reaction of benzene radical cation with water. Evidence for the reversibility of hydroxyl radical addition to benzene

Cited by 47 publications

References 1 publication

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

Hydroxyl Radical (OH^•) Reaction with Guanine in an Aqueous Environment: A DFT Study

Facile selective detritylation of 5?-primary alcohols of pyrimidine nucleosides using tetra-n-butylammonium peroxydisulfate

Contact Info

Product

Resources

About

Reaction of benzene radical cation with water. Evidence for the reversibility of hydroxyl radical addition to benzene

Cited by 47 publications

References 1 publication

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

Hydroxyl Radical (OH•) Reaction with Guanine in an Aqueous Environment: A DFT Study

Facile selective detritylation of 5?-primary alcohols of pyrimidine nucleosides using tetra-n-butylammonium peroxydisulfate

Contact Info

Product

Resources

About

Hydroxyl Radical (OH^•) Reaction with Guanine in an Aqueous Environment: A DFT Study