Metal-ion-promoted hydrolysis of methyl 8-hydroxyquinoline-2-carboxylate
- 1 January 1977
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 19,p. 1866-1874
- https://doi.org/10.1039/dt9770001866
Abstract
Base hydrolysis of the title compound (EH) has been studied over the range pH 9.18–12.1 and values of kOH determined for EH (kOH 4.0 dm3 mol–1 s–1) and for the anion E–(kOH 0.485 dm3 mol–1 s–1) at 25 °C and I= 0.1 mol dm–3. Formation constants KME+ have been obtained at 25 °C and I= 0.1 mol dm3 for the equilibrium M2++ E–⇌[ME]+ using both spectrophotometric and kinetic methods. Rate constants for the base hydrolysis of the [ME]+ complexes (MII= MnII, CoII, NiII, CuII, or ZnII) have been determined together with the values of ΔH‡ and ΔS‡ at 298 K. Quite large rate accelerations are observed (103–106) when comparisons are made with the base hydrolysis of E–. The origin of the rate accelerations is discussed in terms of the thermodynamic activation parameters obtained and possible mechanisms for the reaction are considered.Keywords
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