A photoionization study of trifluoromethanol, CF3OH, trifluoromethyl hypofluorite, CF3OF, and trifluoromethyl hypochlorite, CF3OCl
摘要:
CF 3 OH , an important and controversial by-product of atmospheric decomposition of CF3CFH2 (HFC-134a) and other hydrofluorocarbons, has been examined by photoionization mass spectrometry. The ionization onset is characterized by a broad Franck–Condon distribution, arising primarily from a substantial elongation of the C–O bond upon ionization. An upper limit to the adiabatic ionization potential (IP) of ⩽13.08±0.05 eV has been established. The appearance potentials (APs) of the first two fragments have been accurately determined by fitting with appropriate model functions as AP0(CF2OH+/CF3OH)⩽13.830±0.005 eV and AP0(CF3+/CF3OH)⩽13.996±0.005 eV. While the exact nature of the lowest-energy fragment (nominally CF2OH+) is not clear, the CF3+ fragment threshold leads unambiguously to ΔHf 298∘(CF3OH)⩾−217.2±0.9 kcal/mol and D298(CF3–OH)⩽115.2±0.3 kcal/mol. With previously derived ΔHf 298∘(CF3O)=−151.8−1.1+1.7 kcal/mol, this yields D298(CF3O–H)=117.5−1.4+1.9 kcal/mol, very close to, or only slightly weaker than the O–H bond energy in water: D298(CF3O–H)–D298(HO–H)=−1.8−1.4+1.9 kcal/mol≈0 kcal/mol. Similarly, with the recently redetermined value for ΔHf∘(CF2O), this implies a 298 K reaction enthalpy for the 1,2-elimination of HF from CF3OH of 2.8−1.1+1.7 kcal/mol. CF3OF and CF3OCl have also been examined by photoionization. CF3OF produces a very weak parent, with an apparent adiabatic IP(CF3OF)⩽12.710±0.007 eV. An analysis of the CF3+ and CF2O+ fragments from CF3OF, when combined with literature data, suggests ΔHf 298∘(CF3OF)=−176.9−1.3+1.8 kcal/mol. The fitted value for the appearance potential of CF3+ from CF3OCl, AP0(CF3+/CF3OCl)⩽12.85±0.01 eV, leads to ΔHf 298∘(CF3OCl)⩾−175.6±1.0 kcal/mol, D298(CF3–OCl)⩽88.4±0.3 kcal/mol, and D298(CF3O–Cl)⩽52.8−1.5+2.0 kcal/mol.
From hypochlorites to perfluorinated dialkyl peroxides
作者:Jan H. Nissen、Lucas Wickemeyer、Tony Stüker、Simon Steinhauer、Helmut Beckers、Sebastian Riedel
DOI:10.1016/j.jfluchem.2019.109416
日期:2020.2
The synthesis and characterization of the new perfluorinated hypochlorite, undecafluoro-tert-pentyl hypochlorite, (C2F5)(F3C)2COCl, is reported. Its gas-phase infrared, UV/Vis and NMR spectra have been recorded and its spectroscopicproperties are discussed and compared with quantum-chemical predictions and those of other known perfluorinated hypochlorites such as RFOCl [RF = F3C, (F3C)3C, (C2F5)(F3C)2C]
据报道,新的全氟化次氯酸盐,十氟叔丁基戊基次氯酸盐(C 2 F 5)(F 3 C)2 COCl的合成和表征。已记录了其气相红外,UV / Vis和NMR光谱,并讨论了其光谱性质,并将其与量子化学预测以及其他已知的全氟化次氯酸盐如R F OCl [R F = F 3 C,(F 3 C)3 C,(C 2 F 5)(F 3 C)2C]。相应的次氯酸盐的低温光解也提供了合成途径,以其他方式难以获得的全氟化二烷基过氧化物R F OOR F。
Über die Reaktionen von (CH<sub>3</sub>)<sub>4</sub>N<sup>+</sup>I<sup>-</sup>, (CH<sub>3</sub>)<sub>4</sub>
<sub />N<sup>+</sup>ICl<sub>2</sub>
<sup>-</sup>, (CH<sub>3</sub>)<sub>4</sub>N<sup>+</sup>ICl<sub>4</sub>
<sup>-</sup> und (CH<sub>3</sub>)<sub>4</sub>N<sup>+</sup>Cl<sup>-</sup> mit Trifluormethylhypochlorit CF<sub>3</sub>OCl / The Reactions of (CH<sub>3</sub>)<sub>4</sub>N<sup>+</sup>I<sup>-</sup>, ( CH<sub>3</sub>)<sub>4</sub>N<sup>+</sup>ICl<sub>2</sub>
<sup>-</sup>, (CH<sub>3</sub>)<sub>4</sub>N<sup>+</sup>ICl<sub>4</sub>
<sup>-</sup> and (CH<sub>3</sub>)<sub>4</sub>N<sub>+</sub>Cl<sup>-</sup> with Trifluoromethylhypochlorite CF<sub>3</sub>OCl
作者:Rolf Minkwitz、Raimund Bröchler
DOI:10.1515/znb-1997-0317
日期:1997.3.1
CF3OCl have been demonstrated by the reactions with different iodate salts like (CH3)4N+I-, (CH3)4N+ICl2- and (CH3)4N +ICl4- . At -70°C all reactions give hexafluoroiodate(V ) salts IF6- . In contrast, the reaction of CF3OCl with (CH3)4N+Cl+ yields (CH3)4N+OCF3-. The products have been characterized by vibrational and NMR spectra.
N,N-Difluoro-O-trifluoromethyl-hydroxylamine, CF3ONF2: conformation and vibrational analysis studied by experimental and theoretical methods
作者:Mauricio F. Erben、Carlos O. Della Védova、Helge Willner
DOI:10.1016/j.molstruc.2004.01.001
日期:2004.4
Abstract Infrared spectra in the gas phase and in argon matrix and Raman spectra in the liquid phase were recorded for N , N -difluoro- O -trifluoromethyl-hydroxylamine, CF 3 ONF 2 . The presence of one single conformer could be demonstrated by heating the Ar/CF 3 ONF 2 mixture at different temperatures between 20 and 245 °C with subsequent quenching of the mixture at 15 K as a matrix due to the absence
摘要 记录了N , N -二氟-O -三氟甲基-羟胺,CF 3 ONF 2 的气相和氩基体红外光谱以及液相中的拉曼光谱。可以通过在 20 到 245 °C 之间的不同温度下加热 Ar/CF 3 ONF 2 混合物,随后在 15 K 下将混合物作为基质淬灭,以证明存在一种单一的构象异构体,因为相对没有任何变化。红外矩阵光谱的波段强度。根据量子化学计算(B3LYP 和 B3PW91/6-311+G(3df) 和 MP2/6-311+G*),syn 构象(氮孤对相对于 C-O 键的 syn 取向,δ( CON:)=0°) 是首选。经计算,第二种内部形式(δ (CON:)=165°))的能量高约 5 kcal/mol。