A complete and sustained organic/inorganic reaction mechanism of Baeyer’s test
Department of Organic Chemistry, Faculty of Chemistry, National Autonomous University of Mexico, Mexico City (CDMX), Mexico.
Research Article
World Journal of Chemical and Pharmaceutical Sciences, 2024, 04(02), 001–005.
Article DOI: 10.53346/wjcps.2024.4.2.0023
Publication history:
Received on 11 March 2024; revised on 26 April 2024; accepted on 29 April 2024
Abstract:
The Baeyer’s test for unsaturation has been used in Qualitative Organic Analysis for a long time. However, if an alkaline reagent is used, compounds having an active hydrogen (carbon acids) also give a positive test with potassium permanganate, detracting the test for unsaturation. The first steps of the reaction sequence have been described but the next stages are missing. These are very important because they involve the formation mode of the observed end product, brown manganese dioxide.
In this communication, a complete and sustained reaction mechanism is provided for both reaction mediums, neutral and alkaline. It is in accordance with observed experimental facts. The missing steps are a redox reaction between hypomanganate and permanganate ions, and a second cyclic intermediate now formed with manganate ion. The instability of this intermediate leads directly to manganese dioxide and alkalinization of the neutral medium, as observed experimentally.
Keywords:
Carbon acids; Cyclic hypomanganate ester; Molecular scission; Qualitative Organic Analysis; Redox reaction; Test for unsaturation
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