Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Solvated electrons in liquid ammonia at - 60°C (0.03 M LiCl) can be electrogenerated in the presence of power ultrasound and are shown to be essentially inert under these conditions in the presence of 3-methylanisole (3-MA). The fast mass transport and mixing induced by power ultrasound is then used to monitor the homogeneous Birch reduction process facilitated by the addition of ethanol as a proton source. Pseudo first-order kinetics for both the reduction of 3-MA and the unwanted formation of hydrogen is observed and analysed quantitatively. The rate laws proposed by Greenfield and Schindewolf (A. Greenfield, U. Schindewolf, Ber. Bunsenges. Phys. Chem. 102 (1998) 1808) for the reduction of protons, - (d[e-]/dt) = kH[CH3CH2OH][e-][Li+], and for the Birch reduction of 3-MA, - (d[e-]/dt) = kA[CH3CH2OH][e-][Li+] [3-MA], are confirmed by varying the concentrations [CH3CH2OH] and [3-MA]. The rate constants kH = 2 ± 0.2 M-2 s-1 and kA = 700 ± 100 M-3 s-1 at -60°C are determined and employed for the optimisation of the product yield and current efficiency. Fast mass transport and electrode depassivation induced by power ultrasound are shown to maximise the current efficiency observed for the electrochemical Birch reduction process and to allow the process to be conducted in the presence of a high ethanol concentration and therefore with high overall rate. © 2001 Elsevier Science B.V.

Original publication

DOI

10.1016/S0022-0728(01)00368-0

Type

Journal article

Journal

Journal of Electroanalytical Chemistry

Publication Date

13/07/2001

Volume

507

Pages

144 - 151