Pentafluoroethyl Iodide Research Articles

Original Method of Synthesis of Pentafluoroethyl Iodide

Original Method of Synthesis of Pentafluoroethyl Iodide

Addition of some unreactive fluoroalkanes to tetrafluoroethylene.: Direct catalytic synthesis of F-butene-2

Condensation of trifluoromethanes, CF 3X (X = H, Cl, Br, I), with tetrafluorethylene to form the corresponding F- n-propyl adducts have been carried out with aluminum chlorofluoride as catalyst. Yields of C 3F 7I and C 3F 7Br are especially good, making these useful perfluoropropyl intermediates readily available. Details of the reactions, especially the presence of low percentages of perfluoroisopropyl iodide and bromide in the products, are accounted for by proposed mechanisms involving halonium intermediates. Longer-chain primary iodides can also be added to tetrafluoroethylene, but the final products are predominantly fluoroolefins, with pentafluoroethyl iodide as a byproduct. In the case of the addition of C 2F 5I to tetrafluoroethylene, conditions for an efficient, low temperature dimerization of terafluoroethylene to F-butene-2 catalyzed by a combination of C 2F 5I/aluminum chlorofluoride have been defined. Evidence for an unusual transfer of I + from the iodonium derivative of F-butene-2 to tetrafluoroethylene is presented.

A new and concise method for the synthesis of 5-trifluoromethylisoxazoles

A highly effective synthesis of a series of 5-trifluoromethylisoxazoles 4 from pentafluoroethyl iodide ( 1) and various alkynes 2 by a two-step sequence is described.

ChemInform Abstract: Nucleophilic Addition of the Pentafluoroethyl Group to Aldehydes, Ketones, and Esters.

AbstractThe aldehydes and ketones (Ia) ‐ (Ic) react with pentafluoroethyl iodide (II) in the presence of methyllithium to produce the pentafluoroethylalkanols (III).

Low-threshold solar-pumped laser using C2F5I

Solar-pumped lasing was achieved with pentafluoroethyl iodide, C2F5I, a new alkyl-iodide. Output power and energy of 350 mW and 45 mJ were achieved. This lasant was found to have the lowest lasing threshold of any solar-pumped gas laser to date at approximately 100 solar constants. Such low threshold enables the use in space of simple, trough solar collectors.

Pentafluoroethyllithium. Generation and use in synthesis

Pentafluoroethyl iodide undergoes a rapid exchange reaction with methyllithium at −78°C in the presence of ketones to produce pentafluoroethyl-substituted tertiary carbinols in high yield.

ChemInform Abstract: REACTION OF PENTAFLUOROETHYL RADICALS WITH HYDROGEN CYANIDE

The reaction of C2F5 radicals with HCN has been studied over the range of 533–673 K using the pyrolysis of pentafluoroethyl iodide as the free-radical source. Arrhenius parameters for the reaction relative to C4F10 recombination are given by where θ = 2.303RT kJ/mol and kH/k is in cm3/2/mol1/2·s1/2.

The nascent translational energy of difluorocarbene produced in IR MPD of the pentafluoroethyl radical

We report upon the direct detection of difluorocarbene following infrared multiphoton photolysis of pentafluoroethyl iodide using well-defined (SLM, TEM 00, 80 ns pulse width) TEA CO 2-laser pulses. The rate of appearance of CF 2 at 1 mTorr pressure and RRKM modelling of the unimolecular dissociation of C 2F 3I and C 2F 5 using reasonable input parameters are presented. These support a mechanism whereby CF 2 is produced by secondary photolysis of pentafluoroethyl radicals. Measurements of the velocity of CF 2 by the transient diffusion technique lead to an estimate of 2.6 kcal/mol for its average translational energy acquired from the homolytic cleavage of the CI and CC bonds. This value is higher than that predicted from the models using reasonable spontaneous dissociation rates ( = 10 9 s −1). An inherent assumption of the models is that the excess energy of dissociation is distributed statistically among the vibrational modes of the reaction complex and that there are no small barriers in the exit channel.

Reaction of pentafluoroethyl radicals with hydrogen cyanide

AbstractThe reaction of C2F5 radicals with HCN has been studied over the range of 533–673 K using the pyrolysis of pentafluoroethyl iodide as the free‐radical source. Arrhenius parameters for the reaction equation image relative to C4F10 recombination are given by where θ = 2.303RT kJ/mol and kH/k is in cm3/2/mol1/2·s1/2.

Isotopic labelling at natural abundance. Photolysis of pentafluoroethyl in the infrared multiphoton decomposition of pentafluoroethyl iodide

The combination of isotopically selective infrared multiphoton dissociation with gas chromatography-mass spectrometry provides a powerful assessment of reaction mechanisms. In the case of IR MPD of pentafluoroethyl iodide strong evidence for the homogeneous gas-phase photolysis of the transient C 2F 5 radical is obtained.

Ion-molecule reactions in trifluoromethyl iodide and pentafluoroethyl iodide

Ion-molecule reactions in trifluoromethyl iodide and pentafluoroethyl iodide were studied using time-of-flight and ion cyclotron resonance mass spectrometry, respectively, to obtain information about reaction rates and mechanistic pathways. In the CF 3I system, CF 3 + reacts with parent via F − transfer (exoergic) or via charge exchange (strongly endoergic). The I + ion reacts by I atom abstraction (exoergic) giving I 2 + or by endoergic charge exchange. The parent ion CF 3I + can decay via collisionally induced dissociation, but also undergoes condensation reactions with neutral CF 3I yielding CF 3I 2 + and the dimer ion (CF 3I) 2 +; the ether-structure product (CF 3) 2I + was not seen. Many of the same reaction types are seen in the C 2F 5I system. The CF + ion undergoes I − and CF 3 − transfer reactions with parent, giving C 2F 5 + and CF 2I +, respectively. As in the CF 3I system, CF 3 + (and also CF 2I + and C 2F 5 +) react with substrate either via energetically favorable F − transfer or via strongly unfavorable charge transfer processes, giving C 2F 4I + and C 2F 4I +, respectively, with each reactant. Again, I − reacts by energetically favorable I atom abstraction or unfavorable charge transfer. Endoergic charge transfer also occurs between parent and C 2F 4 + ion. Two condensation products were seen which are analogous to the methyl case — namely C 2F 5I 2 + and (C 2F 5I) 2 +. In both the CF 3I and C 2F 5I systems, there is strong evidence for participation of ions with as much as 1.5 eV of excitation energy.

An electron impact investigation of pentafluoroethyl iodide

An electron impact investigation on C 2F 5I was made using the Retarding Potential Difference technique in a Bendix time-of-flight mass spectrometer. Appearance potentials were measured as follows: CF 3 +, 13.73 eV; C 2F 5 +, 11.71 eV; and C 2F 5I +, 10.66 eV. From these results and previously published values it is possible to derive Δ H f 0(C 2F 5I) ⩾ −236.4 kcal mol −1; Δ H f 0(C 2F 5I +) ⩽ +9.4 kcal mol −1, and D(C 2F 5I) ⩽ 47.0 kcal mol −1. Observation of certain reaction channels in a parallel Ion Cyclotron Double Resonance experiment suggests that Δ H f 0(C 2F 4I +) = +82.0 ± 2 kcal mol −1. From the latter result it is also possible to derive that D(FC 2F 4I +) = 91.5 kcal mol −1. In principle, D(CF 3CF 2I) could also be established if Δ H f 0(CF 2I) were known. If D(FCF 2I) is estimated as 120 kcal mol −1, then Δ H f 0(CF 2I) = −40 kcal mol −1, and D(CF 3CF 2I) ⋍ 79 kcal mol −1. Uncertainties of ±0.1 eV are assigned to appearance potentials and ±2 kcal mol −1 to heats of formation.

Kinetics of the gas phase reaction of pentafluoroethyl iodide with hydrogen iodide. Enthalpy of formation of the pentafluoroethyl radical and the .pi. bond dissociation energy in tetrafluoroethylene

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of the gas phase reaction of pentafluoroethyl iodide with hydrogen iodide. Enthalpy of formation of the pentafluoroethyl radical and the .pi. bond dissociation energy in tetrafluoroethyleneE-Chung Wu and A. S. RodgersCite this: J. Am. Chem. Soc. 1976, 98, 20, 6112–6115Publication Date (Print):September 1, 1976Publication History Published online1 May 2002Published inissue 1 September 1976https://doi.org/10.1021/ja00436a007RIGHTS & PERMISSIONSArticle Views148Altmetric-Citations40LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (416 KB) Get e-Alerts Get e-Alerts

The exchange reaction of pentafluoroethyl iodide with iodine.

The exchange reaction of pentafluoroethyl iodide with iodine.