12381-92-9Relevant academic research and scientific papers
Mechanism of ketone hydrosilylation by Cu(I) catalysts: A theoretical study
Gathy, Thomas,Peeters, Daniel,Leyssens, Tom
, p. 3943 - 3950 (2009)
The plausibility of the catalytic cycle suggested for the hydrosilylation of ketones by Cu(I) hydrides has been investigated by a theoretical DFT study. A model system made up of a CuH(PH3)2 catalyst, acetone and SiH4 give
Rate Constants, Branching Ratios, and Energy Disposal for Nf(b,a,X) and HF(v) Formation from the H + NF2 Reaction
Malins, R.J.,Setser, D. W.
, p. 1342 - 1349 (1981)
The rate constant and energy disposal for the H + NF2 reaction has been measured by observing infrared and visible chemiluminescence in a fast-flow, low concentration, flowing-afterglow apparatus at room temperature.The rate constant was determined by comparing the HF(v) emission intensity to the HCl(v) emission intensity from the H + Cl2 reaction.The rate constant for formation of HF(v >=1) is 3.8 x 1E-12 cm3 molecule -1 s-1.Allowance for HF(v=0) formation gives a total rate constant which is about a factor of 3 larger.The observed HF(v1, v2, v3, v4) distribution is0.75: 0.20: 0.04: 0.01.The NF(a1Δ-X3Σ-) emission also was observed; the NF(a1Δ) vibrational distribution is v0:v1:v2 = 0.73:0.19:0.08.Comparison of the NF(b1Σ+) and NF(a1Δ) emission intensities and using the HF(v = 4) emission, which is energetically allowed only for formation of NF(X3Σ-), gave NF(X):NF(a):NF(b) branching fractions of 0.07:0.91:0.02.By comparing the NF(a1Δ-X3Σ-) intensity from H + NF2 to the HF(3-0) emission intensity from the H + ClF reaction and by using the known rate constant and energy disposal for H + ClF, the radiative lifetime of NF(a1Δ) was determined to be 5.6 s.The 0-0, 1-1, and 2-2 band wavelengths of the NF(a1Δ-X3Σ-) transition yielded οe' = 1184 cm-1 and οe'ξe' = 8.5 cm -1.
Absolute rate coefficients for F+H2 and F+D2 at T=295-765K
Heidner, R. F.,Bott, J. F.,Gardner, C. E.,Melzer, J. E.
, p. 4815 - 4821 (1980)
The rate coefficients of the F+H2 and F+D2 reactions must be accurately known over a wide temperature range if the HF and DF chemical lasers are to be properly modeled.Although the pulsed and cw chemical lasers operate at elevated temperatures (500 to 2000 K), no absolute rate data exist for T>400 K.Extension of the infrared multiphoton dissociation-infrared fluorescence technique permitted the following Arrhenius equations to be determined between 295 and 765 K: kF+H2=(1.3+/-0.25)*1014 exp; kF+D2=(6.4+/-2.2)*1013 exp; kF+H2/kF+D2=(2.1+/-0.8) exp.
Structures and Properties of trans-1,3,3,3-Tetrafluoro- propene (HFO-1234ze) and 2,3,3,3-Tetrafluoropropene (HFO-1234yf) Refrigerants
Flierl, Lukas,Glodde, Timo,Kornath, Andreas J.,Mitzel, Norbert W.,Schwabedissen, Jan,Stammler, Hans-Georg,Vishnevskiy, Yury V.
, p. 921 - 928 (2020)
The refrigerant trans-1,3,3,3-tetrafluoropropene (HFO-1234ze) is used as a replacement for former cooling agents that have been phased-out due to their global warming potential or ozone depleting potential. Although it is used on a large scale, only a few vibrational data and no structural data of HFO-1234ze are known. We report structure determinations based on low-temperature single-crystal X-ray diffraction data as well as gas-phase diffraction data of HFO-1234ze and HFO-1234yf (2,3,3,3-tetrafluoropropene). Furthermore, vibrational spectra of HFO-1234ze in all phases are described. The results are discussed together with quantum-chemical calculations on the PBE0/cc-pVTZ level of theory. Combustion experiments of HFO-1234ze show carbonyl difluoride, carbon dioxide and hydrogen fluoride to be the main combustion products.
Thermal decomposition of 2,2-bis(difluoroamino) propane studied by FTIR spectrometry and quantum chemical calculations: The primary dissociation kinetics and the mechanism for decomposition of the (CH3)2CNF2 radical
Park,Chakraborty,Jamindar,Xia,Lin,Bedford
, p. 101 - 111 (2002)
The kinetics of the thermal decomposition of 2,2-bis(difluoroamino) propane (BDFP) has been studied by pyrolysis/FTIR spectrometry at temperatures between 528 and 553 K using toluene as radical scavenger. The disappearance of BDFP was found to follow the first-order kinetics with the rate constant, k1 = 1016.0±0.7 exp[-(24200 ± 840)/T] s-1, which agrees closely with the expression obtained by Fokin et al. [Dokl. Akad. Nauk. 332 (1993) 735], k1 = 1015.60 exp(-23600/T) s-1. The measured large A-factor supports the earlier conclusion that the primary fragmentation process corresponds to the breaking of one of the two NF2 groups. The measured activation energy is also consistent with the predicted first C-N bond dissociation energy, 44-48 kcal/mol, by the hybrid density-functional theory and that evaluated by variational RRKM calculations fitting the observed rate constant, 47.9 kcal/mol. The 2-difluoroamino propyl radical, (CH3)2CNF2, was predicted to be thermally unstable, producing readily F atoms and HF molecules via the (CH3)2CFNF intermediate. The quantum-chemically predicted mechanisms for the fragmentation of (CH3)2C(NF2)2 and (CH3)2CNF2 agree with the product distribution reported by Ross and coworkers.
The temperature dependence of absolute rate constans for the F+H2 and F+D2 reactions
Wurzberg, E.,Houston, P. L.
, p. 4811 - 4814 (1980)
Multiphoton dissociation of SF6 has been used to generate a transient concentration of fluorine atoms in mixtures with argon and H2 or D2.Absolute rate constans for the F+H2 and F+D2 reactions have been determined as a function of temperature by monitoring the appearance rate of HF or DF product chemiluminescence.In the temperature range from 190 deg K to 373 deg K the results are fit by the expressions kH=1.0*10-10 exp(-(860+/-100)/RT) and kD=9.1*10-11 exp(-(1100+/-100)/RT), both in cm3 molecule-1sec-1.These values are in rough agreement with those obtained recently using a similar technique.The value of the isotope effect kH/kD is in good agreement with two previously determined values.
The rate of the F + H2 reaction at very low temperatures
Tizniti, Meryem,Le Picard, Sebastien D.,Lique, Francois,Berteloite, Coralie,Canosa, Andre,Alexander, Millard H.,Sims, Ian R.
, p. 141 - 145 (2014)
The prototypical F + H2 → HF + H reaction possesses a substantial energetic barrier (～800 K) and might therefore be expected to slow to a negligible rate at low temperatures. It is, however, the only source of interstellar HF, which has been detected in a wide range of cold (10-100 K) environments. In fact, the reaction does take place efficiently at low temperatures due to quantum-mechanical tunnelling. Rate constant measurements at such temperatures have essentially been limited to fast barrierless reactions, such as those between two radicals. Using uniform supersonic hydrogen flows we can now report direct experimental measurements of the rate of this reaction down to a temperature of 11 K, in remarkable agreement with state-of-the-art quantum reactive scattering calculations. The results will allow a stronger link to be made between observations of interstellar HF and the abundance of the most common interstellar molecule, H 2, and hence a more accurate estimation of the total mass of astronomical objects.
IR multiple photon dissociation of fluorinated ethanes and ethylenes: HF vibrational energy distributions
Quick, C. R.,Wittig, C.
, p. 1694 - 1700 (1980)
The IR multiple photon dissociation of fluorinated ethanes and ethylenes produces vibrationally excited HF via collisionless molecular elimination.The HF(excit.) fluorescence spectra have been measured and analyzed in order to determine the relative vibrational level populations produced by the dissociation processes.These results are compared to those obtained by others who used alternate methods of excitation.The measured vibrational level distributions cannot be adequately represented by single temperature Boltzmann distributions or by a statistical partitioning of the available energy.It is estimated that less than 30percent of the fixed energy appears as vibrational excitation of the HF fragment.
Primary Energy Distribution in the Products of the Reaction F + HBr -> HF(ν') + Br
Aker, P. M.,Donaldson, D. J.,Sloan, J. J.
, p. 3110 - 3116 (1986)
It is shown that the title reaction creates HF with approximately the maximum vibrational and rotational excitation permitted by the exoergicity.Thus it appears to exhibit the same dynamics as the other members of the X + HY reaction family (X,Y halogen atoms).This result was obtained from a low-pressure infrared chemiluminescence experiment in which special procedures were introduced to show the absence of all gas-phase and surface energy transfer processes which might distort the measured distribution.
Reaction of limonene with F2: Rate coefficient and products
Bedjanian, Yuri,Romanias, Manolis N.,Morin, Julien
, p. 10233 - 10239 (2014)
The kinetics of the reaction of limonene (C10H16) with F2 has been studied using a low pressure (P = 1 Torr) and a high pressure turbulent (P = 100 Torr) flow reactor coupled with an electron impact ionization and chemical ionization mass spectrometers, respectively: F2 + Limonene → products (1). The rate constant of the title reaction was determined under pseudo-first-order conditions by monitoring either limonene or F2 decay in excess of F2 or C10H16, respectively. The reaction rate constant, k1 = (1.15 ± 0.25) × 10-12 exp(160 ± 70)/T) was determined over the temperature range 278-360 K, independent of pressure between 1 (He) and 100 (N2) Torr. F atom and HF were found to be formed in reaction 1, with the yields of 0.60 ± 0.13 and 0.39 ± 0.09, respectively, independent of temperature in the range 296-355 K. (Graph Presented).
