{"title":"无氯微波辅助离子液体催化的芳基磺酸与醇的酯化反应:实验和理论研究。","authors":"Bianka Huszár , Zoltán Mucsi , György Keglevich","doi":"10.1039/d4ob01516a","DOIUrl":null,"url":null,"abstract":"<div><div>In the area of esterification of heteroatomic acids, after the microwave-assisted ionic liquid-catalyzed esterification of phosphinic acids, the esterification of arylsulfonic acids was also developed applying a 14-fold excess of alcohols at 200 °C in the presence of 10% butyl-methylimidazolium hexafluorophosphate as an additive. The esterifications were optimized, and the effect of the substituents in the aromatic ring was evaluated. At the same time, a similar procedure described by Mandal <em>et al.</em> using only one equivalent of alcohol at 120 °C for 5 min in toluene was refuted. The mechanism and energetics of the reaction of benzenesulfonic acid and butyl alcohol were determined at the B3LYPD3/def2TZVP[PCM(BuOH)] level of theory using the explicit–implicit solvent model, and, as a comparison, the implicit solvent model. Three possible reaction pathways were explored: the direct esterification of benzenesulfonic acid through an S<sub>N</sub>2 protocol including the nucleophilic addition of butyl alcohol to the SO function of the sulfonic acid <em>via</em> an intermediate with a hexavalent-pentacoordinated S atom (<strong><em>Route I</em></strong>), <em>via</em> protonation of the alcohol by the arenesulfonic acid followed by the recombination of the sulfonate anion and the alkyl cation formed by dehydration (<strong><em>Route II</em></strong>), and an S<sub>N</sub>1 route involving the initial formation of a sulfonium cation by dehydration of the protonated sulfonic acid followed by the nucleophilic attack of the alcohol (<strong><em>Route III</em></strong>). Judging from the energetics of the three potential pathways, the alkylating esterification (<strong><em>Route II</em></strong>) seems to be the predominant route. Microwave irradiation may overcome the enthalpy of activation of 132 kJ mol<sup>−1</sup> required for this protocol. The addition–elimination (S<sub>N</sub>2) sequence (<strong><em>Route I</em></strong>) may also be operative as a minor reaction component.</div></div>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":"22 47","pages":"Pages 9249-9258"},"PeriodicalIF":2.9000,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"A chlorine-free microwave-assisted, ionic liquid-catalyzed esterification of arylsulfonic acids with alcohols: an experimental and theoretical study†\",\"authors\":\"Bianka Huszár , Zoltán Mucsi , György Keglevich\",\"doi\":\"10.1039/d4ob01516a\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>In the area of esterification of heteroatomic acids, after the microwave-assisted ionic liquid-catalyzed esterification of phosphinic acids, the esterification of arylsulfonic acids was also developed applying a 14-fold excess of alcohols at 200 °C in the presence of 10% butyl-methylimidazolium hexafluorophosphate as an additive. The esterifications were optimized, and the effect of the substituents in the aromatic ring was evaluated. At the same time, a similar procedure described by Mandal <em>et al.</em> using only one equivalent of alcohol at 120 °C for 5 min in toluene was refuted. The mechanism and energetics of the reaction of benzenesulfonic acid and butyl alcohol were determined at the B3LYPD3/def2TZVP[PCM(BuOH)] level of theory using the explicit–implicit solvent model, and, as a comparison, the implicit solvent model. Three possible reaction pathways were explored: the direct esterification of benzenesulfonic acid through an S<sub>N</sub>2 protocol including the nucleophilic addition of butyl alcohol to the SO function of the sulfonic acid <em>via</em> an intermediate with a hexavalent-pentacoordinated S atom (<strong><em>Route I</em></strong>), <em>via</em> protonation of the alcohol by the arenesulfonic acid followed by the recombination of the sulfonate anion and the alkyl cation formed by dehydration (<strong><em>Route II</em></strong>), and an S<sub>N</sub>1 route involving the initial formation of a sulfonium cation by dehydration of the protonated sulfonic acid followed by the nucleophilic attack of the alcohol (<strong><em>Route III</em></strong>). Judging from the energetics of the three potential pathways, the alkylating esterification (<strong><em>Route II</em></strong>) seems to be the predominant route. Microwave irradiation may overcome the enthalpy of activation of 132 kJ mol<sup>−1</sup> required for this protocol. The addition–elimination (S<sub>N</sub>2) sequence (<strong><em>Route I</em></strong>) may also be operative as a minor reaction component.</div></div>\",\"PeriodicalId\":96,\"journal\":{\"name\":\"Organic & Biomolecular Chemistry\",\"volume\":\"22 47\",\"pages\":\"Pages 9249-9258\"},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2024-09-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Organic & Biomolecular Chemistry\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/org/science/article/pii/S1477052024009388\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CHEMISTRY, ORGANIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organic & Biomolecular Chemistry","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/org/science/article/pii/S1477052024009388","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, ORGANIC","Score":null,"Total":0}
A chlorine-free microwave-assisted, ionic liquid-catalyzed esterification of arylsulfonic acids with alcohols: an experimental and theoretical study†
In the area of esterification of heteroatomic acids, after the microwave-assisted ionic liquid-catalyzed esterification of phosphinic acids, the esterification of arylsulfonic acids was also developed applying a 14-fold excess of alcohols at 200 °C in the presence of 10% butyl-methylimidazolium hexafluorophosphate as an additive. The esterifications were optimized, and the effect of the substituents in the aromatic ring was evaluated. At the same time, a similar procedure described by Mandal et al. using only one equivalent of alcohol at 120 °C for 5 min in toluene was refuted. The mechanism and energetics of the reaction of benzenesulfonic acid and butyl alcohol were determined at the B3LYPD3/def2TZVP[PCM(BuOH)] level of theory using the explicit–implicit solvent model, and, as a comparison, the implicit solvent model. Three possible reaction pathways were explored: the direct esterification of benzenesulfonic acid through an SN2 protocol including the nucleophilic addition of butyl alcohol to the SO function of the sulfonic acid via an intermediate with a hexavalent-pentacoordinated S atom (Route I), via protonation of the alcohol by the arenesulfonic acid followed by the recombination of the sulfonate anion and the alkyl cation formed by dehydration (Route II), and an SN1 route involving the initial formation of a sulfonium cation by dehydration of the protonated sulfonic acid followed by the nucleophilic attack of the alcohol (Route III). Judging from the energetics of the three potential pathways, the alkylating esterification (Route II) seems to be the predominant route. Microwave irradiation may overcome the enthalpy of activation of 132 kJ mol−1 required for this protocol. The addition–elimination (SN2) sequence (Route I) may also be operative as a minor reaction component.
期刊介绍:
Organic & Biomolecular Chemistry is an international journal using integrated research in chemistry-organic chemistry. Founded in 2003 by the Royal Society of Chemistry, the journal is published in Semimonthly issues and has been indexed by SCIE, a leading international database. The journal focuses on the key research and cutting-edge progress in the field of chemistry-organic chemistry, publishes and reports the research results in this field in a timely manner, and is committed to becoming a window and platform for rapid academic exchanges among peers in this field. The journal's impact factor in 2023 is 2.9, and its CiteScore is 5.5.