Coefficients B de viscosité dans les systèmes ternaires aqueux. III. Halogénures alcalins–alcool tert-butylique–eau à 25 °C

1979 ◽  
Vol 57 (24) ◽  
pp. 3247-3252 ◽  
Author(s):  
Marc Palma ◽  
Jean-Pierre Morel
Keyword(s):  
Linear Relationship ◽  
Structural Properties ◽  
Organic Solvents ◽  
Linear Correlation ◽  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Water ◽  
Coefficient Of Viscosity

We have measured the coefficient of viscosity B at 25 °C of HCl, LiCl, NaCl, KCl, RbCl, KI, and KBr in the mixtures of aqueous organic solvents containing from 10 to 40% tert-butyl alcohol by weight (X), the concentration of electrolyte varying from 0.1 to 0.3 M.Plots of B = f (x) show points of inflexion and minima whose positions can be explained by the structural properties of the mixed solvent.In water, a linear relationship between the entropy of hydration and coefficient B of the ions is observed. In the same way, it can be shown that a linear correlation exists between the entropy of solvation and coefficient B of the electrolytes for all the mixtures studied.These correlations lead to the characterization of two distinct zones (X < 20% and X > 20%) for the range of tert-butyl alcohol–water mixtures. [Journal translation]

Diffusive dynamics of water in tert-butyl alcohol/water mixtures

2004 ◽  
Vol 120 (10) ◽  
pp. 4759-4767 ◽  
Author(s):  
Vania Calandrini ◽  
Antonio Deriu ◽  
Giuseppe Onori ◽  
Ruep E. Lechner ◽  
Jörg Pieper
Keyword(s):  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Water ◽  
Diffusive Dynamics

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.

Pressure effect on water dynamics in tert-butyl alcohol/water solutions

2006 ◽  
Vol 18 (36) ◽  
pp. S2363-S2371 ◽  
Author(s):  
Vania Calandrini ◽  
Antonio Deriu ◽  
Giuseppe Onori ◽  
Alessandro Paciaroni ◽  
Mark T F Telling
Keyword(s):  
Pressure Effect ◽  
Butyl Alcohol ◽  
Water Dynamics ◽  
Water Solutions ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Water

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.

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