Chlorine isotope effects in the solvolysis of substituted 1-phenylethyl chlorides

1986 ◽  
Vol 64 (6) ◽  
pp. 1201-1205 ◽  
Author(s):  
Duncan J. McLennan ◽  
Allan R. Stein ◽  
Brian Dobson
Keyword(s):  
Transition State ◽  
Theoretical Calculations ◽  
Isotope Effects ◽  
Chloride Ion ◽  
Solvent Composition ◽  
Solvent Mixtures ◽  
Chlorine Isotope ◽  
Water Solvent ◽  
Alcohol Water ◽  
Substituted 1

Kinetic chlorine isotope effects attending the solvolysis of several ring-substituted 1-phenylethyl chlorides in alcohol–water solvent mixtures are reported. The k35/k37 values are insensitive to the identity of ring substituents and to solvent composition. Results are interpreted in terms of an SN1 heterolytic process incorporating a significant amount of internal return. Theoretical calculations suggest that the incipient chloride ion in the transition state may be strongly hydrogen-bonded.

Enthalpy and entropy of activation for benzyl chloride solvolysis in various alcohol–water solvent mixtures

1968 ◽  
Vol 46 (2) ◽  
pp. 125-129 ◽  
Author(s):  
H. S. Golinkin ◽  
J. B. Hyne
Keyword(s):  
Rate Constants ◽  
Benzyl Chloride ◽  
Solvent Composition ◽  
Solvent Mixtures ◽  
Methyl Ethyl ◽  
First Order ◽  
Water Solvent ◽  
Alcohol Water ◽  
Entropy Of Activation ◽  
Enthalpy And Entropy

The first order rate constants for the solvolysis of benzyl chloride in a series of mixtures of methyl, ethyl, i-propyl, and t-butyl alcohols with water are reported at 40.05 and 60.50 °C. The ΔH* and ΔS* values are calculated using these rate constants and those previously reported at 50.25 °C (1, 2). The dependence of these parameters on solvent composition is discussed.

Solubility and Thermoresponsiveness of PMMA in Alcohol-Water Solvent Mixtures

2010 ◽  
Vol 63 (8) ◽  
pp. 1173 ◽  
Author(s):  
Richard Hoogenboom ◽  
C. Remzi Becer ◽  
Carlos Guerrero-Sanchez ◽  
Stephanie Hoeppener ◽  
Ulrich S. Schubert
Keyword(s):  
Methyl Methacrylate ◽  
Pure Water ◽  
Polymer Concentration ◽  
Polymer Processing ◽  
Solution Temperature ◽  
Solvent Mixtures ◽  
Poly Methyl Methacrylate ◽  
Water Solvent ◽  
Alcohol Water ◽  
Hysteresis Behaviour

To reduce the environmental burden of polymer processing, the use of non-toxic solvents is desirable. In this regard, the improved solubility of poly(methyl methacrylate) (PMMA) in ethanol/water solvent mixtures is very appealing. In this contribution, detailed investigations on the solubility of PMMA in alcohol/water solvent mixtures are reported based on turbidimetry measurements. PMMA revealed upper critical solution temperature transitions in pure ethanol and ethanol/water mixtures. However, around 80 wt-% ethanol content a solubility maximum was observed for PMMA as indicated by a decrease in the transition temperature. Moreover, the transition temperatures increased with increasing PMMA molar mass as well as increasing polymer concentration. Careful analysis of both heating and cooling turbidity curves revealed a peculiar hysteresis behaviour with a higher precipitation temperature compared with dissolution with less than 60 wt-% or more than 90 wt-% ethanol in water and a reverse hysteresis behaviour at intermediate ethanol fractions. Finally, the transfer of poly(styrene)-block-poly(methyl methacrylate) block copolymer micelles from the optimal solvent, i.e. aqueous 80 wt-% ethanol, to almost pure water and ethanol is demonstrated.

scholarly journals Initial state and transition state solvation effects in the oxidation of iodide and catechol by hexachloroiridate(IV) in binary aqueous solvent mixtures

1983 ◽  
Vol 61 (7) ◽  
pp. 1361-1370 ◽  
Author(s):  
Michael J. Blandamer ◽  
John Burgess ◽  
Stephen J. Hamshere ◽  
Colin White ◽  
Robert I. Haines ◽  
...  
Keyword(s):  
Transition State ◽  
State Transition ◽  
Butyl Alcohol ◽  
Activation Process ◽  
Solvent Mixtures ◽  
Redox Systems ◽  
Initial State ◽  
Water Solvent ◽  
Aqueous Solvent ◽  
And Diffusion

Rate constants are reported for hexachloroiridate(IV) oxidation of iodide in methanol–, ethanol–, t-butyl alcohol–, ethylene glycol–, glycerol–, acetone–, acetonitrile–, and dimethyl sulphoxide – water solvent mixtures, and for the hexachloroiridate(IV) oxidation of catechol in methanol–water mixtures. With the aid of ancillary solubility data and measurements, solvent effects on reactivity have been analysed into initial state and transition state components. In the latter, there are probably both electron transfer and diffusion contributions since it is not possible to identify uniquely the separate kinetic steps associated with the activation process. In these redox systems, however, transition state solvation changes dominate. This conclusion is compared with initial state – transition state effects in the reaction of catechol with hexahydroxoantimonic acid, in the bromate oxidation of bromide, the peroxodisulphate oxidation of iodide, and with patterns established earlier for substitution at inorganic centres. In view of some disagreements and uncertainties in the literature concerning the number of molecules of water of crystallisation in potassium hexachloroiridate(III) and hexachloroiridate(IV), this matter, of considerable importance to hexachloroiridate transfer parameter estimation, is briefly reviewed.

Sign in / Sign up

Export Citation Format

Share Document