Formation of tert-butyl cation in methane

1976 ◽  
Vol 54 (11) ◽  
pp. 1739-1743 ◽  
Author(s):  
K. Hiraoka ◽  
P. Kebarle
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Arrhenius Plot ◽  
Ion Source ◽  
Probable Mechanism ◽  
Positive Temperature ◽  
Phase Reaction ◽  
Source Pressure ◽  
Gas Phase Reaction ◽  
Pure Methane

The reactions of CH3+ with pure methane in the torr range show an interesting temperature dependence. C2H5+ is formed at all temperatures by the well known reaction: CH3+ + CH4 = C2H5+ + H2. In the lowest temperature interval studied (105–125 K) C2H5+ adds two CH4 molecules to give a C4H13+ species. At higher temperatures only one CH4 molecule is added on. The resulting C3H9+ then reacts with one more CH4 molecule according to reaction 6.[Formula: see text]The rate constant k6 is found to be second order and has a positive temperature dependence. An Arrhenius plot gives:[Formula: see text]At temperatures above 200 K reaction 6 ceases to occur since C3H9+, being unstable at high temperatures, decomposes to s-C3H7+ + H2.The reactions were studied using ultra pure methane irradiated with electrons in a pulsed beam high ion source pressure mass spectrometer.The gas phase reaction mechanism for the formation of t-C4H9+ is found to bear close re-semblance to the probable mechanism by which the t-C4H9+ ion is formed from methane dissolved in superacid media.

Alkylation of benzene by alkyl cations. Stability of the tert-butyl benzenium ion

1982 ◽  
Vol 60 (18) ◽  
pp. 2325-2331 ◽  
Author(s):  
D. K. Sen Sharma ◽  
S. Ikuta ◽  
P. Kebarle
Keyword(s):  
Gas Phase ◽  
Equilibrium Constants ◽  
Ion Source ◽  
Phase Reaction ◽  
Source Pressure ◽  
Pulsed Electron Beam ◽  
Gas Phase Reaction ◽  
Alkyl Cations ◽  
Alkylation Of Benzene ◽  
Energy Formula

The kinetics and equilibria of the gas phase reaction [1] tert-C4H9+ + C6H6 = tert-C4H9C6H6+ were studied with a high ion source pressure pulsed electron beam mass spectrometer. Equilibria [1] could be observed in the temperature range 285–325 K. van't Hoff plots of the equilibrium constants led to [Formula: see text] and [Formula: see text]. The rate constants at 305 K were klf = 1.5 × 10−28 molecules−2 cm6 s−1 and klr = 2.9 × 10−1 molecules−1 cm3 s−1. tert-C4H9C6H6+ dissociates easily via [lr] not only because of the low dissociation energy [Formula: see text] but also because of the unusually favorable entropy [Formula: see text]. The occurrence of transalkylation reactions: tert-C4H9C6H6+ + alkylbenzene = tert-C4H9 alkylbenzene+ + benzene, was discovered in the present work.

ChemInform Abstract: Temperature Dependence of the Gas-Phase Reaction HOSO2 + O2 → HO2 + SO3

ChemInform ◽  
1988 ◽  
Vol 19 (37) ◽  
Author(s):  
J. F. GLEASON ◽  
C. J. HOWARD
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Phase Reaction ◽  
Gas Phase Reaction

scholarly journals Temperature dependence of rate coefficients for the gas phase reaction of OH with 3-chloropropene. A theoretical and experimental study

2020 ◽  
Vol 755 ◽  
pp. 137757
Author(s):  
Mariela Aguilera Sammaritano ◽  
Mauro González Vera ◽  
Pablo Marcelo Cometto ◽  
Tatiane Nicola Tejero ◽  
Glauco F. Bauerfeldt ◽  
...  
Keyword(s):  
Experimental Study ◽  
Temperature Dependence ◽  
Gas Phase ◽  
Rate Coefficients ◽  
Phase Reaction ◽  
Gas Phase Reaction

Pressure and Temperature Dependence of the Gas-Phase Reaction of SO3with H2O and the Heterogeneous Reaction of SO3with H2O/H2SO4Surfaces

1997 ◽  
Vol 101 (51) ◽  
pp. 10000-10011 ◽  
Author(s):  
John T. Jayne ◽  
Ulrich Pöschl ◽  
Yu-min Chen ◽  
David Dai ◽  
Luisa T. Molina ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Heterogeneous Reaction ◽  
Phase Reaction ◽  
Gas Phase Reaction

Pressure and temperature dependence of the gas-phase reaction of silylene with dimethyl ether

2001 ◽  
Vol 3 (15) ◽  
pp. 3085-3094 ◽  
Author(s):  
Ula N. Alexander ◽  
Keith D. King ◽  
Warren D. Lawrance
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Dimethyl Ether ◽  
Phase Reaction ◽  
Gas Phase Reaction

scholarly journals Temperature Dependence of Rate Constant for the Gas-phase Reaction of Ozone with Linalool

2016 ◽  
Vol 45 (9) ◽  
pp. 1102-1104 ◽  
Author(s):  
Jun Matsumoto
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Rate Constant ◽  
Phase Reaction ◽  
Gas Phase Reaction

scholarly journals Pyrolysis of C2H7+ and other Ion–Molecule Reactions in Methane containing Traces of Ethane

1975 ◽  
Vol 53 (15) ◽  
pp. 2268-2274 ◽  
Author(s):  
Margaret French ◽  
Paul Kebarle
Keyword(s):  
Temperature Dependence ◽  
Proton Affinity ◽  
Preexponential Factor ◽  
Thermal Reaction ◽  
Ion Source ◽  
Positive Temperature ◽  
Source Pressure ◽  
Pulsed Electron Beam ◽  
Ion Molecule Reactions ◽  
Higher Temperature

The major reactions in methane containing traces of ethane were studied with a pulsed electron beam high ion source pressure mass spectrometer. The CH4: C2H6 ratios were changed from 50:1 to 100 000:1 at reaction temperatures between 28–210 °C. The reaction 1: CH5+ + C2H6 = CH4 + C2H7+ still proceeded from left to right even at the highest dilution ratios. Measurement of the C2H7+/CH5+ ratio under these conditions leads to a lower limit of the proton affinity difference PA(C2H6)–PA(CH4) > 10 kcal/mol. This result is in agreement with measurements by Bohme.It was observed that C2H7+ decomposes slowly at 30 °C. The decomposition becomes more rapid at higher temperature. Measurements of the temperature dependence of the thermal reaction 2: C2H7+ + CH4 = C2H5+ + H2 + CH4, and an Arrhenius plot of k2 led to the activation energy E2 = 10.5 kcal/mol and preexponential factor A2 = 8.3 × 10−8 (cm3 molecule−1 s−1). Assuming E2 = ΔH2 one obtains ΔHf(C2H7+) = 208.5 ± 2 kcal/mol and PA(C2H7+) = 137.4 ± 2 kcal/mol. This is close to the proton affinity PA(C2H7+) = 139 ± 2 kcal/mol that can be deduced from Bohme's results.At higher dilution ratios the ion C2H5+ was observed to react not only with ethane but also with methane by reaction 6: C2H5+ + CH4 = C3H7+ + H2, k6 ≈ 1 × 10−14 cm3 molecule−1 s−1 at 86 °C. The reaction has positive temperature dependence.

Pressure and temperature dependence of the gas-phase reaction between methyl and hydroxyl radicals

1994 ◽  
Vol 224 (1-2) ◽  
pp. 43-50 ◽  
Author(s):  
Kjell Fagerström ◽  
Anders Lund ◽  
Gharib Mahmoud ◽  
Jerzy T. Jodkowski ◽  
Emil Ratajczak
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Phase Reaction ◽  
Gas Phase Reaction
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