Gas-phase SN2 reactions of chloride ion with alkyl bromides at atmospheric pressure. Temperature dependence of the rate constants and energies of the transition states

1993 ◽  
Vol 115 (25) ◽  
pp. 12079-12084 ◽  
Author(s):  
W. B. Knighton ◽  
J. A. Bognar ◽  
P. M. O'Connor ◽  
E. P. Grimsrud
Keyword(s):  
Temperature Dependence ◽  
Gas Phase ◽  
Rate Constants ◽  
Atmospheric Pressure ◽  
Transition States ◽  
Chloride Ion ◽  
Sn2 Reactions ◽  
Alkyl Bromides

Temperature Dependence of Disproportionation–Combination Ratios for Alkyl Radicals in Liquid Methane

1971 ◽  
Vol 49 (17) ◽  
pp. 2861-2867 ◽  
Author(s):  
Hugh A. Gillis
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Gas Phase ◽  
Rate Constants ◽  
Room Temperature ◽  
Transition States ◽  
Alkyl Radicals ◽  
Liquid Methane ◽  
Ethyl Radicals

The ratios of rate constants for disproportionation to combination have been measured for ethyl radicals and for i-propyl radicals in liquid methane between −181 and −94 °C. The radicals were generated by γ-radiolysis of dilute methane solutions of ethylene-d4 or propylene-d6. The activation energy for combination was found to exceed that for disproportionation by 290 ± 30 cal mol−1 for ethyl radicals and by 255 ± 25 cal mol−1 for i-propyl radicals. In both cases the disproportionation—combination ratio in the liquid, extrapolated to room temperature, is greater than that in the gas phase by a factor of about 2.5. These results are interpreted as indicating that disproportionation and combination reactions proceed by way of different transition states.

Studies in solvolysis. Part VIII. An entropy correlation related to the reaction of various nucleophiles with malachite green

1977 ◽  
Vol 55 (4) ◽  
pp. 686-692 ◽  
Author(s):  
Stephen Harvey Morris ◽  
John Marshall William Scott ◽  
Frederick Steele
Keyword(s):  
Temperature Dependence ◽  
Malachite Green ◽  
Methyl Iodide ◽  
Rate Constants ◽  
Transition States ◽  
Reaction Coordinate ◽  
Similar Correlation ◽  
Displacement Reactions

The entropies of activation related to the reactions of aqueous malachite green with the nucleophiles water, hydroxide, hydrazine, ammonia, hypochlorite, and sulphite have been calculated from the temperature dependence of the rate constants appropriate to these reactions. The entropies of the transition states for these reactions have been characterized and the transition states shown to be 'reactant like'. A similar correlation, based on data for a series of nucleophiles attacking methyl iodide, suggests that the transition states for the SN2 displacement reactions are also 'reactant like' with respect to the attacking nucleophile. A relationship between two distinct parameters each of which is related to the position of transition states along the reaction coordinate is considered.

Gas-phase reaction of two unsaturated ketones with atomic Cl and O3: kinetics and products

2015 ◽  
Vol 17 (18) ◽  
pp. 12000-12012 ◽  
Author(s):  
Jing Wang ◽  
Li Zhou ◽  
Weigang Wang ◽  
Maofa Ge
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Atmospheric Pressure ◽  
Phase Reaction ◽  
Unsaturated Ketones ◽  
Gas Phase Reaction

The rate constants and products for the reactions of atomic Cl and O3 molecule with 3-methyl-3-buten-2-one (MBO332) and 3-methyl-3-penten-2-one (MPO332) were determined in a 100 L Teflon chamber at 293 ± 1 K and atmospheric pressure.

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