Ab initio, DFT and transition state theory calculations on 1,2-HF, HCI and CIF elimination reactions from CH<sub>2</sub>F–CH<sub>2</sub>Cl

Rajakumar, B.; Arunan, E.

doi:10.1039/b306833a

Cited by 35 publications

(59 citation statements)

References 39 publications

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“…According to Figure a, the sensing materials exhibited obvious UV absorption signals at 210 nm and signal attenuation with the increase of desorption time. Meanwhile, the FT-IR spectra with absorbance at 713, 673, and 655 cm –1 revealed the adsorption of 1,2-DCE, which is shown in Figure b; these UV and FT-IR adsorption data demonstrated the co-adsorption of ozone and 1,2-DCE and were also consistent with the relevant reports and calculations. − …”

Section: Resultssupporting

confidence: 83%

Ozone-Activated Cataluminescence Sensor System for Dichloroalkanes Based on Silica Nanospheres

et al. 2021

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The detection and monitoring of dichloroalkanes, which are typical chlorinated volatile organic compounds (CVOCs) with obvious biological toxicity, is of significance for environmental pollution and public health. Herein, a novel ozone-activated cataluminescence (CTL) sensor system based on silica nanospheres was developed for highly sensitive and fast quantification of dichloroalkanes. A typical CTL system coupled with a plasma-ozone-assist unit was designed for promoting the CTL response of dichloroalkanes. The ozone generated by plasma provides a new pathway of catalytic oxidation process, which accompanied by the CTL signal amplification of dichloroalkanes results in an enhanced CTL sensor system with improved limit of detection (1,2-dichloroethane: 0.04 μg mL −1 , 1,2-dichloropropane: 0.03 μg mL −1 ) and benign selective performance under the interference of CO 2 , H 2 O, NO, NO 2 , SO 2 , CS 2 , and other common CVOCs. Moreover, a segmented CTL mechanism including coadsorption of ozone and dichloroalkanes, thermal elimination, the ozonation route, and a luminous step was ratiocinated based on multiple characterizations and discussion. The proposed methodology and theory open up an attractive perspective for the analysis of less active volatile organic compounds.

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Section: Resultssupporting

confidence: 83%

Ozone-Activated Cataluminescence Sensor System for Dichloroalkanes Based on Silica Nanospheres

et al. 2021

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“…HF elimination from FE has been the subject of a few prior theoretical studies, 9,[44][45][46][47][48][49] although by current standards, none have been at a particularly high level. The highest level previous calculations are the CCSD(T)/6-311++G(d,p) calculations of Hase and coworkers.…”

Section: Dissociationmentioning

confidence: 99%

An experimental and theoretical high temperature kinetic study of the thermal unimolecular dissociation of fluoroethane

Giri

Kiefer

et al. 2008

Phys. Chem. Chem. Phys.

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The thermal dissociation of fluoroethane has been studied using shock tube (ST)/time-of-flight mass spectrometry (TOF-MS) at 500 and 1200 Torr over the temperature range 1200-1550 K. The ST/TOF-MS experiments confirm that elimination of HF is the only reaction channel and rate coefficients for this reaction were extracted from concentration/time profiles derived from the mass spectra. Results from a novel diaphragmless shock tube coupled to the TOF-MS are also presented and demonstrate the unique ability of this apparatus to generate sufficiently reproducible shock waves that signal averaging can be performed over multiple experiments; something that is not possible with a conventional shock tube. The dissociation is also studied with ab initio transition state theory based master equation simulations. A modest increase in the calculated barrier height (i.e., by 1 kcal mol(-1)) yields predicted high pressure rate coefficients that are in good agreement with the existing literature data. The present pressure dependent observations are accurately reproduced for a downwards energy transfer for neon at 1200 to 1500 K of approximately 270 cm(-1), which is somewhat smaller than that found in previous studies on fluorinated ethanes with the same bath gases.

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“…Indeed, the elimination of HX (X = Cl, F) in syn without the intervention of an oxidizing agent has been studied experimentally and theoretically in the case of simple Cl and F substituted ethane derivatives and would present energy barriers of the order of 60 kcal/mol for HCl and HF elimination. [37,38] However, in our case, the presence of I2 in the reaction mixture very likely promotes the elimination of HI and IBr. In the case of the unsubstituted or the 2,3-disubstituted compounds the final helicene compounds are the same regardless whether the elimination of two molecules of HI occurs from the initially formed DH or the transposed forms DHS.…”

Section: S3-s83 and Tablesmentioning

confidence: 56%

Reactivity and Mechanistic Issues in the Photocyclization of Dihalostyryl‐Naphthalenes towards Halo‐[4]helicenes: A Transposition on a Mallory Theme

et al. 2021

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One of the most straightforward strategies nowadays for the synthesis of carbo-and heterohelicenes is the oxidative photocyclisation of stilbene derivatives in the Mallory conditions. In this study, the reactivity of a series of 3,4-dihalostyryl-naphthalenes (Hal = Br, F and Cl) has been investigated in the Mallory conditions towards the corresponding halogenated [4]helicene compounds. The difluoro precursor afforded the two isomeric 2,3-and 1,2-difluoro-[4]helicenes, resulting from the ring closure on the two possible positions of the substituted benzene ring, the dichloro compound led to the formation of a mixture of the two isomeric 2,3 and 1,2-dichloro-[4]helicenes together with the 2-mono-chloro derivative, while the dibromo precursor provided, unexpectedly, only 2,3-dibromo-[4]helicene and the 2-mono-bromo derivative. DFT calculations performed on the entire series of precursors, final helicenes and intermediate dihydrohelicenes, including the non-halogenated congeners, reveal the highly energetically favorable formation of a second dihydrohelicene intermediate following a [1,9]hydrogen sigmatropic transposition. Whereas the existence of this transposed dihydrohelicene intermediate, more stable than the initially formed dihydrohelicene by fifteen to thirty kcal/mol, was hitherto "hidden" in the non-substituted series, it allows here to explain its re-aromatization through formal elimination of HX in order to provide the 2-mono-halogenated-[4]helicene derivatives.

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Ab initio, DFT and transition state theory calculations on 1,2-HF, HCI and CIF elimination reactions from CH₂F–CH₂Cl

Cited by 35 publications

References 39 publications

Ozone-Activated Cataluminescence Sensor System for Dichloroalkanes Based on Silica Nanospheres

Ozone-Activated Cataluminescence Sensor System for Dichloroalkanes Based on Silica Nanospheres

An experimental and theoretical high temperature kinetic study of the thermal unimolecular dissociation of fluoroethane

Reactivity and Mechanistic Issues in the Photocyclization of Dihalostyryl‐Naphthalenes towards Halo‐[4]helicenes: A Transposition on a Mallory Theme

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Ab initio, DFT and transition state theory calculations on 1,2-HF, HCI and CIF elimination reactions from CH2F–CH2Cl

Cited by 35 publications

References 39 publications

Ozone-Activated Cataluminescence Sensor System for Dichloroalkanes Based on Silica Nanospheres

Ozone-Activated Cataluminescence Sensor System for Dichloroalkanes Based on Silica Nanospheres

An experimental and theoretical high temperature kinetic study of the thermal unimolecular dissociation of fluoroethane

Reactivity and Mechanistic Issues in the Photocyclization of Dihalostyryl‐Naphthalenes towards Halo‐[4]helicenes: A Transposition on a Mallory Theme

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Ab initio, DFT and transition state theory calculations on 1,2-HF, HCI and CIF elimination reactions from CH₂F–CH₂Cl