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Low-temperature heat capacity and pseudorotation in 2-methyltetrahydrofuran
Dmitriy Yu Ilin1, Sergey V Tarazanov2, Valeriy V Andreychev1
1Department of Chemistry, Lomonosov Moscow State University, 1-3 Leninskie Gory, Moscow, 119991, Russia. dorofeeva@phys.chem.msu.ru.
Physical Chemistry Chemical Physics : PCCP
|February 16, 2022
Summary
This study measured the heat capacity of 2-methyltetrahydrofuran using calorimetry, revealing insights into its phase transitions and conformational behavior. The findings clarify pseudorotation discrepancies and provide thermodynamic data for this cyclic ether.
Area of Science:
- Physical Chemistry
- Thermodynamics
- Computational Chemistry
Background:
- 2-Methyltetrahydrofuran (2-MTHF) is a cyclic ether with complex conformational dynamics.
- Understanding its thermodynamic properties and phase transitions is crucial for chemical applications.
- Discrepancies in interpreting pseudorotation in 2-MTHF necessitate further investigation.
Purpose of the Study:
- To experimentally determine the heat capacity and phase transitions of 2-MTHF.
- To calculate thermodynamic functions and gas-phase entropy for 2-MTHF.
- To elucidate the conformational features and pseudorotation of 2-MTHF through combined experimental and computational methods.
Main Methods:
- Adiabatic calorimetry was employed to measure heat capacity from 7 to 350 K.
- Smoothed molar thermodynamic functions and formation functions were calculated.
- Quantum chemical calculations were performed to study pseudorotation and conformational potentials.
Main Results:
- Experimental thermodynamic functions in the condensed state were determined.
- Gas-phase entropy was obtained, aiding in the clarification of pseudorotation interpretations.
- Quantum chemical analysis supported experimental findings, indicating intramolecular conversion between low-energy conformers.
Conclusions:
- The study provides comprehensive thermodynamic data for 2-MTHF.
- Pseudorotation in 2-MTHF is best explained by conversion between two conformers with a low-energy transition state.
- Calculated standard thermodynamic properties for gaseous 2-MTHF are valuable for further research.
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