Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt Reaction
In this study, the homogeneous carboxylation of potassium, sodium, and lithium phenolates in DMSO solution at 100 °C by the Kolbe–Schmitt reaction was investigated. The impact of water, phenolate concentration, and cation nature on the yield of products and reaction selectivity was demonstrated. Bas...
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2025-01-01
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| author | Dmitry A. Merzliakov Michael S. Alexeev Maxim A. Topchiy Dmitry G. Yakhvarov Nikolai Yu. Kuznetsov Anton L. Maximov Irina P. Beletskaya |
| author_facet | Dmitry A. Merzliakov Michael S. Alexeev Maxim A. Topchiy Dmitry G. Yakhvarov Nikolai Yu. Kuznetsov Anton L. Maximov Irina P. Beletskaya |
| author_sort | Dmitry A. Merzliakov |
| collection | DOAJ |
| description | In this study, the homogeneous carboxylation of potassium, sodium, and lithium phenolates in DMSO solution at 100 °C by the Kolbe–Schmitt reaction was investigated. The impact of water, phenolate concentration, and cation nature on the yield of products and reaction selectivity was demonstrated. Based on the patterns observed, it was concluded that a complex cluster mechanism governs the carboxylation reaction in the solution. The use of a homogeneous reaction medium allowed for convenient testing of various additives to assess their impact on the reaction. Basic additives such as sodium salts of mesitol, <i>tert</i>-butylcalix[4]arene, sodium isopropyl, and <i>tert</i>-butyl cabonates were found to enhance the reaction, increasing the yield of hydroxybenzoic acids by 20% (to 61.6%). The main product in the DMSO solution was identified as 4-hydroxybenzoic acid, in contrast to the classical Kolbe–Schmitt method which typically yields 2-hydroxybenzoic (salicylic) acid. The use of <sup>13</sup>C NMR spectroscopy enabled the observation of a “carbonate complex” in the solution for the first time, with the carbonate carbon displaying a chemical shift value of 142 ppm, an unusual finding for stable carbonates, and located between the signals of free dissolved CO<sub>2</sub> and carboxylate derivatives. |
| format | Article |
| id | doaj-art-84891ff71aac49758c27377f25099269 |
| institution | Kabale University |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
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| series | Molecules |
| spelling | doaj-art-84891ff71aac49758c27377f250992692025-01-24T13:43:15ZengMDPI AGMolecules1420-30492025-01-0130224810.3390/molecules30020248Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt ReactionDmitry A. Merzliakov0Michael S. Alexeev1Maxim A. Topchiy2Dmitry G. Yakhvarov3Nikolai Yu. Kuznetsov4Anton L. Maximov5Irina P. Beletskaya6A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow 119991, RussiaA.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow 119991, RussiaA.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow 119991, RussiaFederal Research Center Kazan Scientific Center of Russian Academy of Sciences, Lobachevskogo St. 2/31, Kazan 420111, RussiaA.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow 119991, RussiaA.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow 119991, RussiaA.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow 119991, RussiaIn this study, the homogeneous carboxylation of potassium, sodium, and lithium phenolates in DMSO solution at 100 °C by the Kolbe–Schmitt reaction was investigated. The impact of water, phenolate concentration, and cation nature on the yield of products and reaction selectivity was demonstrated. Based on the patterns observed, it was concluded that a complex cluster mechanism governs the carboxylation reaction in the solution. The use of a homogeneous reaction medium allowed for convenient testing of various additives to assess their impact on the reaction. Basic additives such as sodium salts of mesitol, <i>tert</i>-butylcalix[4]arene, sodium isopropyl, and <i>tert</i>-butyl cabonates were found to enhance the reaction, increasing the yield of hydroxybenzoic acids by 20% (to 61.6%). The main product in the DMSO solution was identified as 4-hydroxybenzoic acid, in contrast to the classical Kolbe–Schmitt method which typically yields 2-hydroxybenzoic (salicylic) acid. The use of <sup>13</sup>C NMR spectroscopy enabled the observation of a “carbonate complex” in the solution for the first time, with the carbonate carbon displaying a chemical shift value of 142 ppm, an unusual finding for stable carbonates, and located between the signals of free dissolved CO<sub>2</sub> and carboxylate derivatives.https://www.mdpi.com/1420-3049/30/2/248carboxylationCO<sub>2</sub>phenolatesKolbe–Schmitt4-hydroxybenzoic acid2-hydroxybenzoic acid |
| spellingShingle | Dmitry A. Merzliakov Michael S. Alexeev Maxim A. Topchiy Dmitry G. Yakhvarov Nikolai Yu. Kuznetsov Anton L. Maximov Irina P. Beletskaya Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt Reaction Molecules carboxylation CO<sub>2</sub> phenolates Kolbe–Schmitt 4-hydroxybenzoic acid 2-hydroxybenzoic acid |
| title | Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt Reaction |
| title_full | Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt Reaction |
| title_fullStr | Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt Reaction |
| title_full_unstemmed | Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt Reaction |
| title_short | Development of Homogeneous Carboxylation of Phenolates via Kolbe–Schmitt Reaction |
| title_sort | development of homogeneous carboxylation of phenolates via kolbe schmitt reaction |
| topic | carboxylation CO<sub>2</sub> phenolates Kolbe–Schmitt 4-hydroxybenzoic acid 2-hydroxybenzoic acid |
| url | https://www.mdpi.com/1420-3049/30/2/248 |
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