Several reports of experimentally derived proton affinity values and gas-phase basicity values for amino acids and peptides have recently appeared in the literature. Here, we show that the thermodynamic quantity that is measured by the Fourier transform mass spectrometry proton transfer bracketing o
The thermodynamics and kinetics of the proton-transfer reactions between bromophenol blue and some aromatic amines in aprotic solution
β Scribed by Peter Sheridan; Amanda Ambroziak; Ian Fryer; Anna Priest
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 525 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0538-8066
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β¦ Synopsis
The equilibria and the stopped-flow kinetics of the reaction between the acid bromophenol blue (BPB) and several aromatic amines in toluene to form ion pairs have been investigated. Contrary to expectations, the rate of the proton-transfer increases with increasing activation enthalpy. This is explained in terms of the entropy of the transition state.
The role of the electronic structure of the amine and of the solvent are discussed. Solvent effects were further investigated by comparing the activation parameters for the reaction between BPB and pyridine in chlorobenzene, toluene, and benzene. The solvent clearly plays a vital role in determining the rate of proton-transfer via the entropy of activation. The mechanism of the reaction (that proton-transfer is almost complete in the transition state, and is followed by amine migration and ring opening) is confirmed. 0 1993 John Wiley & Sons, Inc.
π SIMILAR VOLUMES
## Abstract An integrated Feynman path integralβfree energy perturbation and umbrella sampling (PIβFEP/UM) method has been used to investigate the kinetic isotope effects (KIEs) in the proton transfer reaction between nitroethane and acetate ion in water. In the present study, both nuclear and elec