REACTIONS OF THERMAL ENERGY IONS: II. RATES OF SOME HYDROGEN TRANSFER ION–MOLECULE REACTIONS

1966 ◽  
Vol 44 (12) ◽  
pp. 1351-1359 ◽  
Author(s):  
A. G. Harrison ◽  
A. Ivko ◽  
T. W. Shannon
Keyword(s):  
Field Strength ◽  
Rate Constant ◽  
Thermal Energy ◽  
Rate Constants ◽  
Hydrogen Transfer ◽  
Thermal Reaction ◽  
Dipole Model ◽  
Protonated Molecule ◽  
Ion Molecule Reactions ◽  
Induced Dipole

The rate constants for the ion–molecule reactions forming the protonated molecule in CH3CN, H2, CH4, and CH3OCH3, the equivalent reactions in the deuteriated species, and the reactions forming COD+ in CO–CD4 mixtures have been measured at thermal energies and at 10.5 V/cm repeller field strength. For H2, HD, D2 and the reactions in CO–CD4 mixtures the rate constant for the thermal reaction is approximately 0.3–0.5 that of the 10.5 V/cm rate constant. For all other cases the ratio of rate constants is approximately unity as predicted by the ion-induced dipole model. The absolute values of the rate constants in most cases are considerably lower than predicted by theory.

Reactions of thermal energy ions. VI. Hydrogen-transfer ion–molecule reactions involving polar molecules

1967 ◽  
Vol 45 (24) ◽  
pp. 3107-3117 ◽  
Author(s):  
S. K. Gupta ◽  
E. G. Jones ◽  
A. G. Harrison ◽  
J. J. Myher
Keyword(s):  
Mass Spectrometer ◽  
Thermal Energy ◽  
Pressure Measurement ◽  
Rate Constants ◽  
Hydrogen Transfer ◽  
Collision Theory ◽  
Protonated Molecule ◽  
Ion Molecule Reactions ◽  
Dipole Interactions ◽  
Made In

The rate constants for formation of the protonated molecule by ion–molecule reactions in CH3OH, (CH3)2O, and CH4 have been studied both at thermal energies and at 3.4 eV ion exit energy with a new mass spectrometer described in the present work. The rate constants are found to be approximately a factor of two greater than previously measured and it is concluded that an error in pressure measurement was made in the earlier work. Revised rate constants are presented for a number of systems studied previously. The results are compared with predictions of the collision theory modified in this paper to include the effect of ion-dipole interactions.

An ICR mass spectrometry study of ion/molecule reactions between ethyl chloride and alkylamines

1991 ◽  
Vol 69 (2) ◽  
pp. 363-367
Author(s):  
Guoying Xu ◽  
Jan A. Herman
Keyword(s):  
Mass Spectrometry ◽  
Key Words ◽  
Rate Constant ◽  
Rate Constants ◽  
Ethyl Chloride ◽  
Ion Molecule Reactions ◽  
Mass Spectrometry Study ◽  
Ethyl Cation

Ion/molecule reactions in mixtures of ethyl chloride with C1–C4 alkylamines were studied by ICR mass spectrometry. Ethyl cation transfer to C1–C4 alkylamines proceeds mainly through diethylchloronium ions with rate constants ~3 × 10−10cm3 s−1. In the case of s-butylamine the corresponding rate constant is 0.5 × 10−10 cm3 s−1. Key words: ICR mass spectrometry, ion/molecule reactions, ethylchloride, methylamine, ethylamine, propylamines, butylamines

Ion–molecule reactions in formic-d acid and methyl formate

1968 ◽  
Vol 46 (12) ◽  
pp. 2141-2146 ◽  
Author(s):  
Howard Pritchard ◽  
J. C. J. Thynne ◽  
A. G. Harrison
Keyword(s):  
Rate Constants ◽  
Methyl Formate ◽  
Ion Molecule Reactions ◽  
Dipole Interactions ◽  
Induced Dipole ◽  
Energy Formula ◽  
Good Agreement

The following ion–molecules reactions have been found to occur in DCOOH for ions produced by bombardment with electrons of 10–15 eV energy (all rate constants in cm3 molecule−1 units).[Formula: see text]In methyl formate the following reactions have been identified and rate constants measured for ions formed by bombardment with electrons of 10–15 eV energy.[Formula: see text]Experiments using DCO2CH3 show that reaction [f] involves transfer of the methyl hydrogen at a rate 1.5 times that of the formyl hydrogen while reaction [g] involves transfer from only the methyl position of CH3OH+. The rate constants for all reactions are considerably higher than predicted on the basis of ion–induced dipole interactions only but are in good agreement with values calculated by including ion–dipole interactions.

Ion molecule reactions in ethane. Thermochemistry and structures of the intermediate complexes: C4H11+ and C4H10+ formed in the reactions of C2H5+ and C2H4+ with C2H6

1980 ◽  
Vol 58 (21) ◽  
pp. 2262-2270 ◽  
Author(s):  
K. Hiraoka ◽  
P. Kebarle
Keyword(s):  
Low Temperature ◽  
Rate Constant ◽  
Reaction System ◽  
Major Product ◽  
Ion Source ◽  
Source Pressure ◽  
Pulsed Electron Beam ◽  
Ion Molecule Reactions ◽  
High Temperature Reaction ◽  
Induced Dipole

The reactions of C2H5+ and C2H4+ with ethane were studied in a pulsed electron beam high ion source pressure mass spectrometer. Ethane at variable pressures in the 10–100 m Torr range in ~5 Torr hydrogen was used in experiments covering the temperature range −145 to 400 °C. Reaction [7]: C2H5+ + C2H6 = sec-C4H9+ + H2 was found to have a rate constant whose magnitude decreased with temperature: k7 = 10−5.12 T−2 (molecule−1 cm3 s−1). The reaction proceeds via a C4H11+ (b) intermediate, which at low temperature can be stabilized and becomes the major product. The rate constant for thermal decomposition of C4H11(b) by reaction [6t]: C4H11+ (b) = sec-C4H9+ + H2 could be measured. The activation energy was found to be E6t = 9.6 kcal/mol. From consideration of the above data and the known ΔH7, it was concluded that C4H11+ (b) has the structure[Formula: see text]Before dissociation to sec-C4H9+ + H2, this ion rearranges to[Formula: see text]The barrier for this rearrangement is ~9.6 kcal/mol.C2H4+ reacts with C2H6 to give C4H10+ (d) at low temperatures. At high temperatures C4H10+ (d) becomes an intermediate in the dissociation to sec-C3H7+ + H2. The formation of C4H10+ at low temperature has a rate constant whose magnitude decreases with temperature. The temperature dependence of the equilibrium constant K10 for the reaction [10]: C2H4+ + C2H6 = C4H10+ (d) could be determined. This led to ΔH10 = −15.3 kcal/mol. The rate constant for the high temperature reaction [11]: C2H4+ + C2H6 = sec-C3H7+ + H2 was k11 = 8.4 × 10−10 exp (−3.9/RT kcal/mol) (molecule−1 cm3 s−1). A potential energy diagram for the reaction system is proposed. C4H10+ (d) is probably a complex between C2H4+ and C2H6 held largely by ion induced dipole process. Reaction [11] probably proceeds via C4H10+ (d) → n-C4H10+ → sec-C3H7+ + H2. The barrier between C7H10+ (d) and n-C4H10+ is ~20 kcal/mol.

ION–MOLECULE REACTIONS IN METHYL ALCOHOL AND METHYL-d3 ALCOHOL

1966 ◽  
Vol 44 (14) ◽  
pp. 1655-1661 ◽  
Author(s):  
J. C. J. Thynne ◽  
F. K. Amenu-Kpodo ◽  
A. G. Harrison
Keyword(s):  
Methyl Alcohol ◽  
Rate Constants ◽  
Hydrogen Transfer ◽  
Rate Coefficients ◽  
Collision Complex ◽  
Ion Molecule Reactions ◽  
Ion Energies ◽  
Hydroxyl Hydrogen

The rate constants for the hydrogen-transfer ion-molecule reactions[Formula: see text]have been measured at thermal ion energies and found to be 12 × 10−10 cm3 molecule−1 s−1 and 8.0 × 10−10 cm3 molecule−1 s−1 respectively. The rate coefficients at higher ion energies (3.7 eV ion exit energy) show little change from these values. Reactions [a] and [b] have also been studied using CD3OH and it is found that in reaction [a] the hydroxyl hydrogen is transferred 2.5 times more readily at low ion energies and 1.8 times more readily at high ion energies than a methyl hydrogen. This rather small specificity would appear to preclude formation of a "locked-in" collision complex even at low ion energies.

Concurrent ion–molecule reactions. III. Reactions in mixtures of HCl and HCN with D2 and CD4

1967 ◽  
Vol 45 (12) ◽  
pp. 1321-1327 ◽  
Author(s):  
A. G. Harrison ◽  
J. C. J. Thynne
Keyword(s):  
Field Strength ◽  
Cross Sections ◽  
Rate Constants ◽  
The Self ◽  
Ion Molecule Reactions ◽  
Ion Energies

The concurrent ion–molecule reactions in mixtures of HCl and HCN with D2 and CD4 have been studied by the ratio plot method. The following reactions have been detected in mixtures with HCN and their cross sections determined at 10.5 V cm−1 repeller field strength. [Formula: see text]In mixtures of D2 and CD4 with HCl the following reactions have been detected and cross sections determined. [Formula: see text]Rate constants for the self-reactions in HCN and HCl have been measured both at 10.5 V cm1 repeller field and at thermal ion energies.

Determination of rate constants of redox reactions of second order from current-less potential-time curves by a simplified graphical-numerical method

1983 ◽  
Vol 48 (5) ◽  
pp. 1358-1367 ◽  
Author(s):  
Antonín Tockstein ◽  
František Skopal
Keyword(s):  
Numerical Method ◽  
Explicit Form ◽  
Rate Constant ◽  
Optimization Algorithm ◽  
Rate Constants ◽  
Redox Reactions ◽  
Second Order ◽  
Wide Region ◽  
Recurrent Formula

A method for constructing curves is proposed that are linear in a wide region and from whose slopes it is possible to determine the rate constant, if a parameter, θ, is calculated numerically from a rapidly converging recurrent formula or from its explicit form. The values of rate constants and parameter θ thus simply found are compared with those found by an optimization algorithm on a computer; the deviations do not exceed ±10%.

The Effect of p-Toluidine on the Two-Step Electroreduction of Zn(II) in Water-Methanol and Water-Dimethylformamide

1999 ◽  
Vol 64 (4) ◽  
pp. 585-594 ◽  
Author(s):  
Barbara Marczewska
Keyword(s):  
Electron Transfer ◽  
Binary Mixtures ◽  
Rate Constant ◽  
Rate Constants ◽  
Electrode Surface ◽  
Mercury Electrode ◽  
Forward Rate ◽  
Solvent Molecules ◽  
Activated Complex

The acceleration effect of p-toluidine on the electroreduction of Zn(II) on the mercury electrode surface in binary mixtures water-methanol and water-dimethylformamide is discussed. The obtained apparent and true forward rate constants of Zn(II) reduction indicate that the rate constant of the first electron transfer increases in the presence of p-toluidine. The acceleration effect may probably be accounted for by the concept of the formation on the mercury electrode an activated complex, presumably composed of p-toluidine and solvent molecules.

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