Neutral hydrolysis of ketene bis(2-methoxyethyl) acetal in water in the presence of tert-butyl alcohol, tetra-n-butylammonium bromide, and potassium bromide. Effects of hydrophobic hydration

1979 ◽  
Vol 44 (2) ◽  
pp. 297-300 ◽  
Author(s):  
Paul G. J. Huurdeman ◽  
Jan B. F. N. Engberts
Keyword(s):  
Hydrophobic Hydration ◽  
Potassium Bromide ◽  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Hydrolysis Of

Effects of organic solvents on immobilized enzyme catalyses. Chymotrypsin immobilized on Sephadex

1980 ◽  
Vol 58 (23) ◽  
pp. 2633-2640 ◽  
Author(s):  
Diana H. Pliura ◽  
J. Bryan Jones
Keyword(s):  
Enzyme Activity ◽  
Organic Solvents ◽  
Immobilized Enzyme ◽  
Reaction Medium ◽  
Butyl Alcohol ◽  
Native Enzyme ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Catalytic Rate ◽  
Hydrolysis Of

The esterolytic activities of native chymotrypsin (CT) and immobilized CT-Sephadex have been studied in the presence of up to 20% of the organic solvents methanol, ethanol, 2-propanol, tert-butyl alcohol, dioxane, or DMSO. The general cosolvent-induced inhibition of the native enzyme was attenuated for immobilized CT. Most noticeably, the apparent catalytic rate constants for the CT-Sephadex-catalyzed hydrolysis of N-acetyl-L-tyrosine ethyl ester were invariant over the 2–20% dioxane concentration range surveyed. In contrast, the activity of the native enzyme in 20% dioxane was only 3% the activity recorded in the absence of cosolvent. Increasing the hydrophobic character of the protic cosolvents destabilized the native enzyme but stabilized CT-Sephadex. Both native and immobilized CT displayed remarkable stability in 20% aqueous DMSO [Formula: see text]. At least part of the DMSO-induced inhibition of native CT and CT-Sephadex was offset by increasing the apparent pH of the reaction medium. The altered kinetic patterns for CT-Sephadex are best explained by the effects of diffusional limitations on the apparent enzyme activity. The best compromise solvent for preparative applications of CT-Sephadex was found to be tert-butyl alcohol.

Kinetics and mechanism of hydrolysis of substituted phenyl N-(4-methylphenyl)sulphonylcarbamates. Solvolysis of 3-nitrophenyl N-(4-methylphenyl)-sulphonylcarbamate in mixtures water-1,4-dioxane and water-tert-butyl alcohol and its decomposition to neutral molecules in non-aqueous media

1979 ◽  
Vol 44 (9) ◽  
pp. 2639-2652 ◽  
Author(s):  
Jitka Moravcová ◽  
Miroslav Večeřa
Keyword(s):  
Organic Solvents ◽  
Ph Dependence ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Base Catalysis ◽  
Hydrolysis Rate ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Hydrolysis Of

pH Dependence of hydrolysis rate of the substituted phenyl N-(4-methylphenyl)sulphonylcarbamates has been followed in aqueous medium. The activation parameters and the Hammet reaction constant (ρ = 2.4) have been determined at pH 11.3. For hydrolysis of 3-nitrophenyl N-(4-methylphenyl)sulphonylcarbamate (pK about 3.5) no general base catalysis has been found. The hydrolysis mechanism is discussed. Perturbation of the water structure by organic solvents (1,4-dioxane and tert-butyl alcohol) has been used for differentiation of ElcB and Bac2 mechanisms, 2,4-dinitrophenyl acetate being used for comparison. The decomposition rates of 3-nitrophenyl N(4-methylphenyl)sulphonylcarbamate have been determined in six organic solvents. Mechanism of spontaneous splitting of the carbamate molecule in non-aqueous media is discussed.

Hydrophobic hydration of tert-butyl alcohol studied by Brillouin light and inelastic ultraviolet scattering

2011 ◽  
Vol 134 (5) ◽  
pp. 055104 ◽  
Author(s):  
L. Lupi ◽  
L. Comez ◽  
C. Masciovecchio ◽  
A. Morresi ◽  
M. Paolantoni ◽  
...  
Keyword(s):  
Hydrophobic Hydration ◽  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Ultraviolet Scattering

Hydrophobic Hydration in Water–tert-Butyl Alcohol Solutions by Extended Depolarized Light Scattering

2014 ◽  
Vol 119 (29) ◽  
pp. 9236-9243 ◽  
Author(s):  
L. Comez ◽  
M. Paolantoni ◽  
L. Lupi ◽  
P. Sassi ◽  
S. Corezzi ◽  
...  
Keyword(s):  
Light Scattering ◽  
Hydrophobic Hydration ◽  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Depolarized Light Scattering

Hydrophobic hydration of tert-butyl alcohol probed by NMR and IR

2000 ◽  
Vol 85 (1-2) ◽  
pp. 139-152 ◽  
Author(s):  
Kazuko Mizuno ◽  
Yuki Kimura ◽  
Hitomi Morichika ◽  
Yukari Nishimura ◽  
Shinji Shimada ◽  
...  
Keyword(s):  
Hydrophobic Hydration ◽  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

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