Thermodynamical properties of ε-caprolactone

Emel′yanenko, Vladimir N.; Verevkin, Sergey P.; Stepurko, E. N.; Roganov, G. N.; Georgieva, M. K.

doi:10.1134/s0036024410030039

Cited by 16 publications

(12 citation statements)

References 10 publications

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“…These results are in line with the results of previous quantum chemical investigations of caprolactone13, 26 or cycloheptane 7. For the latter molecule, Cremer found that B and TB forms have the same puckering amplitudes of 1.163 Å and undergo almost free pseudorotation.…”

Section: Resultssupporting

confidence: 91%

“…ε‐Caprolactone introduces an oxygen atom and the ester sp 2 ‐hybridized C atom into the seven‐membered ring, but retains much of the conformational flexibility of cycloheptane, making interesting a comparison with the prototype molecule. A recent conformational search by Groenewald and Dillen13 extended previous force field,25 density functional theory (DFT), and Gaussian 3 (G3) studies,26 and suggested five stable conformers with relative energies lower than 21 kJ mol −1 and interconversion barriers up to 67 kJ mol −1 . The objectives of our investigation were to verify these predicted conformers by a two‐pronged approach combining modern MW spectroscopy21–23, 27 with high accuracy quantum chemical calculations based on a systematic use of the CP puckering coordinates.…”

Section: Introductionmentioning

confidence: 88%

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Pseudorotational Landscape of Seven‐Membered Rings: The Most Stable Chair and Twist‐Boat Conformers of ε‐Caprolactone

Jahn

Dewald

Vallejo‐López

et al. 2014

Chemistry A European J

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The conformational landscape and ring-puckering properties of ε-caprolactone have been analyzed by using microwave spectroscopy and quantum chemical calculations. Two conformers were detected in a supersonic jet expansion, the most stable form being a chair containing the ester group in its rectangular flap. This conformation benefits from reduced CH2 bond eclipsing and angle strain, while π-electron delocalization in the ester group is increased. The derived effective structure of the chair form satisfactorily agrees with the calculated near-equilibrium structure. A twist-boat conformer was also identified (9.4 kJ mol(-1) higher in energy at CCSD(T)/aug-cc-pVTZ level), and was located in the boat-twist-boat pseudorotation cycle of the seven-membered ring. Three other low-energy conformers were investigated and characterized in terms of the four puckering coordinates of the seven-membered ring. Potential interconversions in the four-dimensional conformation space are also discussed.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 88%

Pseudorotational Landscape of Seven‐Membered Rings: The Most Stable Chair and Twist‐Boat Conformers of ε‐Caprolactone

Jahn

Dewald

Vallejo‐López

et al. 2014

Chemistry A European J

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“…The melting properties of HA were measured by DSC and given in Figure 3. The melting temperature (T m ) of HA is 350.75 K and the enthalpy of fusion (△ fus H) is calculated as 19.9 kJ•mol -1 , which are consistent with literature data (T m =351.3 K, △ fus H=19.3 kJ•mol -1 ) [19]. The density of HA obtained from literature is 1.49 g•cm -3 (293.15 K) [20].…”

Section: Characterization and Identification Of Materialssupporting

confidence: 83%

Thermodynamic equilibrium of hydroxyacetic acid in pure and binary solvent systems

Huang

Xie

et al. 2017

The Journal of Chemical Thermodynamics

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The solubility of hydroxyacetic acid in five pure organic solvents and two binary solvent mixtures were experimentally measured from 273.15 K to 313.15 K at atmospheric pressure (p=0.1 MPa) by using a dynamic method. The order of solubility in pure organic solvents is ethanol > isopropanol > n-butanol > acetonitrile > ethyl acetate within the investigated temperature range, except for temperature lower than 278 K where the solubility of HA in ethyl acetate is slightly larger than that in acetonitrile. Furthermore, the solubility data in pure solvents were correlated with the modified Apelblat model, NRTL model, and Wilson model and that in the binary solvents mixtures were fitted to the CNIBS/R-K model and Jouyban-Acree model. Finally, the mixing thermodynamic properties of hydroxyacetic acid in pure and binary solvent systems were calculated and discussed.

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“…This hydrolytic degradation mechanism has been previously described and is depicted in Figure S4, Supporting Information. [ 17 ] Since the ceiling temperature of PCL is several hundred degrees Celsius [ 32 ] with an equilibrium constant ( k p ) previously reported as 30.5, [ 33 ] chain coupling and depolymerization were not considered to be the cause of change to the polymer molecular weight and tensile properties. The observed decrease in molecular weight is due to polymer backbone cleavage in the middle of the chain being more entropically favored as opposed to backbone cleavage closer to the polymer chain ends.…”

Section: Resultsmentioning

confidence: 99%

Degradation of Melt Electrowritten PCL Scaffolds Following Melt Processing and Plasma Surface Treatment

Paxton

Tuten

et al. 2021

Macromol. Rapid Commun.

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Melt electrowriting (MEW) has been widely used to process polycaprolactone (PCL) into highly ordered microfiber scaffolds with controllable architecture and geometry. However, the integrity of PCL during specific processes involved in routine MEW scaffold development has not yet been thoroughly investigated. This study investigates the impact of MEW processing on PCL following exposure to high temperatures required for melt extrusion as well as atmospheric plasma, a widely used surface treatment for improving MEW scaffold hydrophilicity. The change in polymer molecular weight and melt temperature is characterized, in comparing unprocessed and processed samples, in addition to analysis of the mechanical and surface properties of the scaffolds. No significant difference in the molecular weight or mechanical properties of the PCL scaffolds is evident following 5 days of cyclic heating to 90 °C. Exposure to plasma for up to 5 min significantly increased hydrophilicity and surface adhesion force, characterized via contact angle and atomic force microscope, however, significant polymer degradation occurred evidenced by increased brittleness of the scaffolds. This study demonstrates the degradation of PCL following fabrication via MEW and surface treatment to guide the optimization of scaffold development for subsequent applications in tissue engineering and biofabrication.

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Thermodynamical properties of ε-caprolactone

Cited by 16 publications

References 10 publications

Pseudorotational Landscape of Seven‐Membered Rings: The Most Stable Chair and Twist‐Boat Conformers of ε‐Caprolactone

Pseudorotational Landscape of Seven‐Membered Rings: The Most Stable Chair and Twist‐Boat Conformers of ε‐Caprolactone

Thermodynamic equilibrium of hydroxyacetic acid in pure and binary solvent systems

Degradation of Melt Electrowritten PCL Scaffolds Following Melt Processing and Plasma Surface Treatment

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