Studies in Solvolysis. Part VII. The Neutral Hydrolysis of Methyl Perchlorate

1975 ◽  
Vol 53 (20) ◽  
pp. 3106-3115 ◽  
Author(s):  
Ross Elmore Robertson ◽  
Adrianna Annesa ◽  
John Marshall William Scott
Keyword(s):  
Heat Capacity ◽  
Carbon Atom ◽  
Temperature Dependence ◽  
Thermodynamic Parameters ◽  
Isotope Effect ◽  
Perchlorate Ion ◽  
Rate Of Hydrolysis ◽  
Leaving Groups ◽  
Hydrolysis Of

The temperature dependence of the rate of hydrolysis of methyl perchlorate has been measured and the entropy (ΔS≠), enthalpy (ΔH≠), and heat capacity (ΔCp≠) of activation calculated. The measurements confirm that the perchlorate ion is superior to all other leaving groups in water. The isotope effect related to the hydrolysis of methyl-d3 perchlorate has been measured at three temperatures and shown to be inverse. The thermodynamic parameters and the isotope effect were examined with respect to the mechanism of substitution at a primary carbon atom.

Neutral Solvolysis of Acyl Carbon and the Temperature Dependence of the Kinetic Solvent Isotope Effect

1975 ◽  
Vol 53 (6) ◽  
pp. 869-877 ◽  
Author(s):  
B. Rossall ◽  
R. E. Robertson
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Solvent Isotope Effect ◽  
Acyl Carbon ◽  
Rate Of Hydrolysis ◽  
Solvent Isotope ◽  
Neutral Conditions ◽  
Hydrolysis Of

The temperature dependence of the rate of hydrolysis of benzoic, phthalic, and succinic anhydrides have been determined in H2O and D2O under "neutral" conditions. Corresponding data have been obtained for methyl trifluoroacetate. While both series supposedly react by the same BAc2 mechanism, remarkable differences are made obvious by this investigation. Possible sources of such differences are proposed.

Hydrolysis of α-bromoisobutyrate ion in water

1967 ◽  
Vol 45 (18) ◽  
pp. 2071-2077 ◽  
Author(s):  
B. N. Hendy ◽  
W. A. Redmond ◽  
R. E. Robertson
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Deuterium Isotope Effect ◽  
Detailed Mechanism ◽  
Temperature Range ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

The temperature dependence of the rate of hydrolysis of α-bromoisobutyrate ion in water was determined over a temperature range 9–37 °C. From these data corresponding values of ΔH≠, ΔS≠, and ΔCP≠ have been derived. The implication of these terms, together with corresponding data for hydrolysis in D2O and for the secondary deuterium isotope effect from the hydrolysis of (CD3)2CBrCOO−, provide a basis for reexamining the detailed mechanism with particular reference to accompanying solvent reorganization.

Heat capacity of activation for the hydrolysis of methanesulfonyl chloride and benzenesulfonyl chloride in light and heavy water

1969 ◽  
Vol 47 (22) ◽  
pp. 4199-4206 ◽  
Author(s):  
R. E. Robertson ◽  
B. Rossall ◽  
S. E. Sugamori ◽  
L. Treindl
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Temperature Dependence ◽  
Heavy Water ◽  
Bond Formation ◽  
Sulfonyl Chlorides ◽  
Benzenesulfonyl Chloride ◽  
Methanesulfonyl Chloride ◽  
Hydrolysis Of ◽  
Parameter Temperature Dependence

Rates of solvolysis of methanesulfonyl chloride and benzenesulfonyl chloride have been determined in H2O and D2O. The free energy, enthalpy, entropy, and heat capacity of activation were calculated. The exceptional accuracy of the data permitted an estimation of dΔCp≠/dT from a four parameter temperature dependence of the kinetic rates.From these data we conclude that both sulfonyl chlorides hydrolyse by the same mechanism (Sn2) The change in R from CH3 to C6H5 in RSO2Cl did not alter ΔCp≠ but ΔS≠ (20°) was changed from −8.32 to −13.25 cal deg−1 mole−1, respectively. The significance of this difference is attributed to the probability of bond formation rather than to differences in solvent reorganization.

The Hydrolysis of Disubstituted Alkyl Phosphorochloridates and N,N,N′,N′-Tetra-stibstituted Phosphorodiamidic Chlorides in Water and Deuterium Oxide: Heat Capacity of Activation and Kinetic Solvent Isotope Effects

1973 ◽  
Vol 51 (4) ◽  
pp. 597-603 ◽  
Author(s):  
E. C. F. Ko ◽  
R. E. Robertson
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Parameters ◽  
Alkyl Group ◽  
Deuterium Oxide ◽  
Isotope Effects ◽  
Potential Relationship ◽  
Mechanism Of Reaction ◽  
Solvent Isotope ◽  
Hydrolysis Of ◽  
Solvent Isotope Effects

The pseudo-thermodynamic parameters, ΔH≠, ΔS≠, and ΔCp≠ and the kinetic solvent isotope effects have been determined for the three alkyl-phosphorochloridates, where the alkyl group is ethylisopropyl and n-propyl; for tetra-methyl and tetra-ethyl phosphorodiamidic chlorides; the di-n-propyl and di-isopropyl analog, the di(isopropylmethylcarbinyl)phosphorochloridate and the tetra-ethylthiophosphorodiamidic chloride. These compounds have a potential relationship to compounds used as insecticides and as polymers. The mechanism of reaction is discussed on the basis of these data.

Solvolysis of sulphonyl halides. V. Hydrolysis and deuterolysis of methanesulphonyl chloride

1970 ◽  
Vol 23 (12) ◽  
pp. 2427
Author(s):  
ML Tonnet ◽  
AN Hambly
Keyword(s):  
Transition State ◽  
Thermodynamic Parameters ◽  
Isotope Effect ◽  
Large Reduction ◽  
Butyl Chloride ◽  
Solvent Isotope Effect ◽  
Initial State ◽  
Solvent Isotope ◽  
Hydrolysis Of

The values of the thermodynamic parameters of activation have been determined for the solvolysis of methanesulphonyl chloride in H2O and D2O and their mixtures with moderate amounts of dioxan. Some of the data are not in agreement with the postulate that the kinetic solvent isotope effect and the maximum in the rate of solvolysis produced by the addition of dioxan are due to changes in the initial state of the reacting system rather than to changes in the transition state. The addition of dioxan does not produce a large reduction in the solvent isotope effect as reported for the hydrolysis of t-butyl chloride and predicted to be general. The relative rates of solvolysis in mixtures of H2O and D2O are not in agreement with the analysis of such reactions by Swain and Thornton.

The Hydrolysis of t-Butyl Chloride in Aquo-Organic Mixtures: Heat Capacity of Activation and Solvent Structure

1972 ◽  
Vol 50 (9) ◽  
pp. 1353-1360 ◽  
Author(s):  
R. E. Robertson ◽  
S. E. Sugamori
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
High Water ◽  
Remarkable Difference ◽  
Solvent Structure ◽  
Butyl Chloride ◽  
Organic Mixtures ◽  
A Value ◽  
Polar Solutes ◽  
Hydrolysis Of

The temperature dependence of the rate of solvolysis of t-butyl chloride in mixtures of tetrahydrofuran and of acetonitrile in water have been determined. In the high-water range both minor co-solvents lead to a reduction in the value of ΔH≠ similar to that found previously where alcohol was the co-solvent. However, a remarkable difference in the values of [Formula: see text] across the same concentration range reflected a difference in the effect of these two co-solvents on the structural properties of the several solvent media. Where tetrahydrofuran or alcohols are the minor co-solvent, [Formula: see text] becomes much more negative until that concentration is reached where the quasi-aqueous structure collapses. Where acetonitrile is the minor co-solvent [Formula: see text] becomes more positive relative to the value found for hydrolysis in water until a value of about −40 cal deg−1 mol−1 is reached. The implication of these findings concerning the nature of solvation of weakly polar solutes in such mixtures is discussed.

Charge Development and Mechanism in Disrotatory Ring Opening of Cyclopropyl Bromides

1974 ◽  
Vol 52 (14) ◽  
pp. 2660-2665 ◽  
Author(s):  
Jan Han Ong ◽  
Ross Elmore Robertson
Keyword(s):  
Transition State ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Isotope Effect ◽  
Ring Opening ◽  
Deuterium Isotope Effect ◽  
Enthalpy Of Activation ◽  
Cis And Trans ◽  
Hydrolysis Of

The temperature dependence of the rates of hydrolysis of cis- and trans-2-vinylcyclopropyl bromides has been determined in water. The temperature coefficient of the enthalpy of activation (ΔCp≠) for both compounds was unusual (−27 and −35 cal mol−1 deg−1). From this fact, it was concluded that the charge development at the transition state was low, in agreement with the conclusions of Clark and Smale (19). The slightly inverse α-deuterium isotope effect (kH/kD = 0.994) is consistent with that conclusion.

REACTIONS OF ARYLSULPHONIC ESTERS: III. ON THE HYDROLYSIS OF METHYL p-METHYLBENZENESULPHONATE

1955 ◽  
Vol 33 (10) ◽  
pp. 1536-1543 ◽  
Author(s):  
R. E. Robertson
Keyword(s):  
Specific Heat ◽  
Temperature Dependence ◽  
Specific Solvation ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Reaction In Water

A study of the temperature dependence for the rate of hydrolysis of methyl p-methylbenzenesulphonate shows the specific heat of activation for this reaction in water to be 33.45 ± 3 cal./mole degree. A comparison with the corresponding term for other methyl compounds reveals differences apparently characteristic of the anionic portion of the molecule. These differences are discussed in terms of specific solvation.

Temperature Dependence of the Carbon Isotope Effect in the Acid Hydrolysis of Urea

1958 ◽  
Vol 80 (8) ◽  
pp. 1835-1838 ◽  
Author(s):  
Peter E. Yankwich ◽  
Audrey E. Veazie
Keyword(s):  
Temperature Dependence ◽  
Acid Hydrolysis ◽  
Carbon Isotope ◽  
Isotope Effect ◽  
Carbon Isotope Effect ◽  
Hydrolysis Of ◽  
Hydrolysis Of Urea
Sign in / Sign up

Export Citation Format

Share Document