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A mechanism of alkali metal carbonates catalysing the synthesis of β-hydroxyethyl sulfide with mercaptan and ethylene carbonate
Dongliang Liu, , Hong Gong, Fei Li, Qiang Li, Lijuan Song, Tamil Azhagan, Heng Jiang, Minghui Yang
Published in Royal Society of Chemistry
2019
Volume: 17
   
Issue: 42
Pages: 9367 - 9374
Abstract
The reaction of β-hydroxyethylation is essential to the current practice of organic chemistry. Here, we proposed a new and green route to synthesize 2-hydroxyethyl n-alkyl sulfide with n-alkyl mercaptan and ethylene carbonate (EC) in the presence of alkali carbonates as catalysts and revealed the mechanism by experiments and theoretical calculations. The reaction reported proceeds rapidly with high yields when it is performed at 120 °C and the catalytic loading is ∼1 mol%. This protocol is applicable to other mercaptans to synthesize the corresponding β-hydroxyethyl sulfide. Density functional theory-based calculations show the energy profile for the reaction pathway. The rate-determining step is the ring-opening of EC. A negatively charged O atom of alkali carbonates approaches the S atom of -SH under the influence of hydrogen bonds. An activated S atom that carries more negative charge serves as a nucleophilic reagent and assists in the ring-opening of EC by reducing the Mayer bond orders of the C1-O1 bond in EC. Alkali cations also contribute to the C1-O1 bond cleavage. The energy barrier for the ring-opening of EC decreases with the decrease of electronegativity of alkali cations. Subsequent transference of a H atom leads to the formation of β-hydroxyethyl sulfide, the dissociation of CO2 and the reduction of K2CO3 © 2019 The Royal Society of Chemistry.
About the journal
JournalData powered by TypesetOrganic and Biomolecular Chemistry
PublisherData powered by TypesetRoyal Society of Chemistry
Open AccessNo
Concepts (16)
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    Atoms
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    Electronegativity
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    Ethylene
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    Hydrogen bonds
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    Positive ions
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    POTASH
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    SULFUR COMPOUNDS
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    ALKALI METAL CARBONATES
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    ETHYLENE CARBONATE
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    MAYER BOND ORDERS
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    Negatively charged
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    NUCLEOPHILIC REAGENT
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    Rate determining step
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    Reaction pathways
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    Theoretical calculations
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    Density functional theory