Electron chemistry. Chemical reactions in CCl4, CFCl3 and CF2Cl2 induced by low-energy electrons

Verhaart, G.J.; Sprang, H. A. van; Brongersma, H.H.

doi:10.1016/0301-0104(80)80113-3

Cited by 11 publications

(4 citation statements)

References 25 publications

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“…(244) Photodecomposition is possible at lower photon energies when the chlorofluoromethanes are adsorbed on surfaces such as grains of sand. (245,246) It has been suggested that weakly bound electrons on these surfaces are responsible for this effect. (244) Electron attachment studies of these compounds are also important because they are most easily detected in the environment using the electron capture detector.…”

Section: Dissociation Of Molecules By Slow Electrons 317mentioning

confidence: 99%

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Dissociation of Molecules by Slow Electrons

Compton

Bardsley

1984

Electron-Molecule Collisions

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Section: Dissociation Of Molecules By Slow Electrons 317mentioning

confidence: 99%

“…Verhaart, van Sprang, and Brongersma (246) have studied the neutral products produced by low-energy « 0.5 eV) electron impact on CCI4, CFCI3, and CF2Cl2.…”

Section: Dissociation Of Molecules By Slow Electrons 317mentioning

confidence: 99%

Dissociation of Molecules by Slow Electrons

Compton

Bardsley

1984

Electron-Molecule Collisions

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confidence: 99%

“…The enthalpy of formation, D f H 298 1, of CCl 2 has been obtained experimentally in numerous ways including kinetic studies, 48 electron impact experiments, 49,53 ion cyclotron resonance techniques, 45,[50][51][52] collision induced dynamics studies, 47,54 and by determination of the ionization potential. 55 Some of these studies, especially the earlier ones, resulted in values below 50 kcal mol À1 : 47 AE 3 kcal mol À1 (1967), 48 44 AE 2 kcal mol À1 (1976), 50 47.8 AE 2 kcal mol À1 (1978), 52 37 AE 7 kcal mol À1 (1980), 53 39 AE 3 kcal mol À1 (1985). 45 In contrast to these, other measurements, including the most recent ones scatter between 51 and 57 kcal mol À1 : 56.5 AE 5 kcal mol À1 (1968), 49 53.8 AE 2 kcal mol À1 (1977), 51 52.1 AE 3.4 kcal mol À1 (1991), 54 51.0 AE 2.0 kcal mol À1 (1993), 55 55.0 AE 2.0 kcal mol À1 (1985).…”

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Accurate ab initio determination of spectroscopic and thermochemical properties of mono- and dichlorocarbenes

Tarczay

Miller

Czakó

et al. 2005

Phys. Chem. Chem. Phys.

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The best technically feasible values for the triplet-singlet energy gap and the enthalpies of formation of the HCCl and CCl2 radicals have been determined through the focal-point approach. The electronic structure computations were based on high-level coupled cluster (CC) methods, up to quadruple excitations (CCSDTQ), and large-size correlation-consistent basis sets, ranging from aug-cc-pVDZ to aug-cc-pV6Z, followed by extrapolation to the complete basis set limit. Small corrections due to core correlation, relativistic effects, diagonal Born-Oppenheimer correction, as well as harmonic and anharmonic zero-point vibrational energy corrections have been taken into account. The final estimates for the triplet-singlet energy gap, T0(ã), are 2170+/-40 cm-1 for HCCl and 7045+/-60 cm-1 for CCl2, favoring the singlet states in both cases. Complete quartic force fields in internal coordinates have been computed for both the X and ã states of both radicals at the frozen-core CCSD(T)/aug-cc-pVQZ level. Using these force fields vibrational energy levels of {HCCl, DCCl, CCl2} up to {6000, 5000, 7000} cm-1 were calculated both by second-order vibrational perturbation theory (VPT2) and variationally. These results, especially the variational ones, show excellent agreement with the experimentally determined energy levels. The enthalpies of formation of HCCl (X1A') and CCl2(X1A1), at 0 K, are 76.28+/-0.20 and 54.54+/-0.20 kcal mol-1, respectively.

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Halogenation of polymers by dichlorodifluoromethane

Das

Adhikari

Maiti

1991

Angew. Makromol. Chem.

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Fluorination of polyethylene and polyvinyl alcohol was carried out by dichlorodifluoromethane under cobalt-60 gamma radiation and under electric spark discharge. The effect of temperature, reaction time, catalyst, inert diluent etc. was studied. Simultaneous chlorination of the polymer samples was observed along with fluorination.The extent of fluorination under electric spark discharge is usually higher than that under gamma radiation. Again, the extent of chlorination is higher than that of fluorination in both the cases. The extent of fluorination as well as chlorination is the highest in case of polyvinyl alcohol. ZUSAMMENFASSUNG:Die Fluorierung von Polyethylen und Polyvinylalkohol wurde mit Dichlordifluormethan CCl,F, (Freon 12) unter Verwendung von Cobalt-60 y-Strahlung bzw. elektrischer Lichtbogenentladung durchgefiihrt und der Einflun von Reaktionstemperatur und -zeit, Katalysator, Verdiinnung etc. untersucht. Dabei wurde bei Polyethylen sowohl die Fluorierung als auch die gleichzeitige Chlorierung beobachtet, wobei der Anteil an Fluorierung bei elektrischer Lichtbogenentladung gewohnlich hoher war als bei Verwendung von y-Strahlung; in beiden Fallen war dennoch die Chlorierung deutlich bevorzugt. Bei Polyvinylalkohol konnten noch hohere Fluorierungs-bzw. Chlorierungsgrade ermittelt werden. cheap, and readily available chemical, i. e. dichlorodifluoromethane gas, as a safe fluorinating agent. In this paper we report the fluorination of polyethylene and a few other polymers by dichlorodifluoromethane under cobalt-60 gamma radiation and under electric spark discharge. Experimental MaterialsLow density polyethylene (LDPE) beads and films (ICI, India), starch (Merck, Germany), and polyvinyl alcohol (Fluka, Switzerland) were used as received. PVC powder (NOCIL, India) was purified by Soxhlet extraction in methanol for 96 h. Dichlorodifluoromethane, Freon-12 (Navin Fluorine Industries, India), was used after drying over preheated silica gel before use. Azobisisobutyronitrile, AIBN (British Drug House, England), was recrystallized from methanol and dried in air. Commercial argon gas was used after purification by passing through alkaline pyrogallate solution. LDPE powder was prepared by dissolving 5 g LDPE beads in 500 ml hot xylene and precipitation in methanol in the form of very fine particles. The precipitate was collected by filtration, washed thoroughly with water and methanol, and air-dried.

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Electron chemistry. Chemical reactions in CCl4, CFCl3 and CF2Cl2 induced by low-energy electrons

Cited by 11 publications

References 25 publications

Dissociation of Molecules by Slow Electrons

Dissociation of Molecules by Slow Electrons

Accurate ab initio determination of spectroscopic and thermochemical properties of mono- and dichlorocarbenes

Halogenation of polymers by dichlorodifluoromethane

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