Nucleophilicity toward Ketenes:  Rate Constants for Addition of Amines to Aryl Ketenes in Acetonitrile Solution

2001 ◽  
Vol 66 (15) ◽  
pp. 5016-5021 ◽  
Author(s):  
N. C. de Lucas ◽  
J. C. Netto-Ferreira ◽  
J. Andraos ◽  
J. C. Scaiano
Keyword(s):  
Rate Constants ◽  
Acetonitrile Solution ◽  
Rate Constants For Addition

ChemInform Abstract: Nucleophilicity Toward Ketenes: Rate Constants for Addition of Amines to Aryl Ketenes in Acetonitrile Solution

ChemInform ◽  
2010 ◽  
Vol 32 (42) ◽  
pp. no-no
Author(s):  
N. C. de Lucas ◽  
J. C. Netto-Ferreira ◽  
J. Andraos ◽  
J. C. Scaiano
Keyword(s):  
Rate Constants ◽  
Acetonitrile Solution ◽  
Rate Constants For Addition

The analysis of muonium hyperfine interaction measurements of thermal rate constants for addition reactions

1991 ◽  
Vol 94 (4) ◽  
pp. 2794-2806 ◽  
Author(s):  
Ronald J. Duchovic ◽  
Albert F. Wagner ◽  
Ralph Eric Turner ◽  
David M. Garner ◽  
Donald G. Fleming
Keyword(s):  
Hyperfine Interaction ◽  
Rate Constants ◽  
Addition Reactions ◽  
Thermal Rate Constants ◽  
Muonium Hyperfine ◽  
Rate Constants For Addition

Substituent effects on the reactivity of the silicon–carbon double bond. Arrhenius parameters for the reaction of 1,1 -diarylsilenes with alcohols and acetic acid

1997 ◽  
Vol 75 (10) ◽  
pp. 1393-1402 ◽  
Author(s):  
Christine J. Bradaric ◽  
William J. Leigh
Keyword(s):  
Acetic Acid ◽  
Proton Transfer ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Substituent Effects ◽  
Activation Energies ◽  
Nucleophilic Attack ◽  
Acetonitrile Solution ◽  
Nanosecond Laser ◽  
Arrhenius Parameters

Absolute rate constants for the reaction of a series of ring-substituted 1,1 -diphenylsilene derivatives with methanol, tert-butanol, and acetic acid in acetonitrile solution have been determined using nanosecond laser flash photolysis techniques. The three reactions exhibit small positive Hammett ρ-values at 23 °C, consistent with a mechanism involving initial, reversible nucleophilic attack at silicon to form a σ-bonded complex that collapses to product via rate-limiting proton transfer. Deuterium kinetic isotope effects and Arrhenius parameters have been determined for the reactions of 1,1-di-(4-methylphenyl)silene and 1,1-di-(4-trifluoromethylphenyl)silene with methanol, and are compared to those for the parent compound. Proton transfer within the complex is dominated by entropic factors, resulting in negative activation energies for reaction. The trends in the data can be rationalized in terms of variations in the relative rate constants for reversion to reactants and proton transfer as a function of temperature and substituent. A comparison of the Arrhenius activation energies for reaction of acetic acid with 1,1-diphenylsilene (Ea = +1.9 ± 0.3 kcal/mol) and the more reactive di-trifluoromethyl analogue (Ea = +3.6 ± 0.5 kcal/mol) suggests that carboxylic acids also add by a stepwise mechanism, but with formation of the complex being rate determining. Keywords: silene, substituent effects, kinetics, Arrhenius, flash photolysis.

Absolute Rate Constants for Hydrocarbon Autoxidation. XXII. The Autoxidation of some Vinyl Compounds

1972 ◽  
Vol 50 (14) ◽  
pp. 2298-2304 ◽  
Author(s):  
J. A. Howard
Keyword(s):  
Rate Constants ◽  
Addition Reaction ◽  
Peroxy Radical ◽  
Stabilization Energy ◽  
Peroxy Radicals ◽  
Absolute Rate ◽  
Termination Rate ◽  
Vinyl Compound ◽  
Rate Constants For Addition

Absolute propagation and termination rate constants have been determined for the autoxidation of some vinyl compounds at 30°. Rates of propagation depend on the structure of both the peroxy radical and the vinyl compound. The reactivity of peroxy radicals towards addition increases as the electron-withdrawing capacity of the α-substituent increases. Rate constants for addition of t-butylperoxy radicals to vinyl compounds, [Formula: see text] fit the equation[Formula: see text]where Es is the estimated stabilization energy of the β-peroxyalkyl radical (in kcal/mol) formed in the addition reaction.

Solvent, Substituent, and Temperature Effects on the Absolute Rate Constants for Addition of Methoxytrimethylsilane to 1,1-Diarylsilenes

2001 ◽  
Vol 20 (5) ◽  
pp. 932-936 ◽  
Author(s):  
William J. Leigh ◽  
Christine J. Bradaric ◽  
Tracy L. Morkin ◽  
Xiaojing Li
Keyword(s):  
Rate Constants ◽  
Temperature Effects ◽  
Absolute Rate ◽  
The Absolute ◽  
Rate Constants For Addition

ChemInform Abstract: Rate Constants for Addition of a Primary Alkyl Radical to Carbon Monoxide.

ChemInform ◽  
2010 ◽  
Vol 27 (14) ◽  
pp. no-no
Author(s):  
K. NAGAHARA ◽  
I. RYU ◽  
N. KAMBE ◽  
M. KOMATSU ◽  
N. SONODA
Keyword(s):  
Carbon Monoxide ◽  
Rate Constants ◽  
Alkyl Radical ◽  
Rate Constants For Addition

Reactions of Substituted Vinyl Cations in Acetonitrile Solution as Studied by Flash Photolysis, Part II

1992 ◽  
Vol 47 (9) ◽  
pp. 1319-1323 ◽  
Author(s):  
Shinjiro Kobayashi ◽  
Wolfram Schnabel
Keyword(s):  
Optical Absorption ◽  
Rate Constants ◽  
Steric Effect ◽  
Flash Photolysis ◽  
Aliphatic Alcohols ◽  
Acetonitrile Solution ◽  
Lifetime Measurements ◽  
Absorption Measurements

Vinyl cations of the structure were generated by flash photolysis of the corresponding halides. Lifetime measurements with the aid of optical absorption measurements yielded bimolecular rate constants k2 of the reaction of I+ with tetrahydrofuran and several aliphatic alcohols. On the basis of k2 values the steric effect of various substituents R1 and R2 at C2 and the combined mesomeric (+M) and inductive (-1) effect of substituent groups at C1 on the electrophilicity of I+ have been elucidated.

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