Abstract
The oxidation of DL-mandelate (MAN–) by [Ag(OH)4]– in strongly alkaline media has been investigated by stopped-flow spectrophotometry. Product analysis shows that benzaldehyde is the sole organic product when MAN– is in excess. The rate law is kobs=(a+b[OH–])[MAN–], where a=(6.2 ± 0.2) dm3 mol–1 s–1 and b=(7.0 ± 0.3) dm6 mol–2s–1 at 25 °C and I= 1.3 mol dm–3. Oxidation of benzaldehyde (to benzoic acid) by AgIII is more than an order of magnitude slower than the mandelate reaction. Activation parameters for both hydroxide-dependent and -independent paths are ΔHa‡=(59.3 ± 2.1) kJ mol–1, ΔSb‡=(–32.0 ± 0.5) J mol–1 K–1 and ΔH‡b=(48.0 ± 2.3) kJ mol–1, ΔSb‡=(–68.5 ± 0.6) J mol–1 K–1 respectively. Two different mechanistic pathways are discussed. A base-catalysed processs, followed by C–C cleavage, seems to be the most probable mode of decarboxylation. The comparative non-reactivity of phenylglyoximate and α-methoxyphenylacetate ions underlines the importance of the α-OH group in the mandelate oxidation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
