Anti-parallel dimer and tetramer formation of propylene carbonate
Raman scattering and infrared (IR) absorption spectra of enantiopure (R)-propylene carbonate ((R)PC) and racemic propylene carbonate (PC) were recorded at room temperature, 25 °C, in benzene (Bz) solution and in the pure liquid state to investigate the presence of dimers and other higher order inter...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2017-09-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/1.5002118 |
| _version_ | 1818241725685039104 |
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| author | Ayana Tagawa Tomoko Numata Toshiyuki Shikata |
| author_facet | Ayana Tagawa Tomoko Numata Toshiyuki Shikata |
| author_sort | Ayana Tagawa |
| collection | DOAJ |
| description | Raman scattering and infrared (IR) absorption spectra of enantiopure (R)-propylene carbonate ((R)PC) and racemic propylene carbonate (PC) were recorded at room temperature, 25 °C, in benzene (Bz) solution and in the pure liquid state to investigate the presence of dimers and other higher order intermolecular associations. (R)PC and PC both demonstrated a strong C=O stretching vibrational band. The band exhibited changes in its shape and resonance wavenumber highly dependent on the concentrations of PCs, whereas a difference between the chirality of (R)PC and PC had little influence. In an extremely dilute condition, doubly split bands were observed at 1807 and 1820 cm-1 in both Raman and IR spectra, which are assigned to the characteristic bands of isolated monomeric PCs. An additional band appeared at 1795 cm-1 in a dilute to concentrated regime, and its magnitude strengthened with increasing concentrations accompanied with slight increasing in the magnitude of 1807 cm-1 band in Raman spectra, while an increase in the magnitude of 1807 cm-1 band was clearly greater than that of 1795 cm-1 band in IR spectra. The spectrum changes at 1795 and 1807 cm-1 were attributed to characteristics of anti-parallel dimer formation of PCs caused by strong dipole-dipole interactions between C=O groups. Moreover, another additional signal was clearly observed at 1780-1790 cm-1 in a concentrated regime, and became the primary signal in the pure liquid state with slight increasing in the intensity of 1795 cm-1 band in Raman spectra. On the other hand, in IR spectra the observed increasing of 1780-1790 cm-1 band was much less than that of 1795 cm-1 band. These newly found spectrum changes in the concentrated regime are attributed to the formation of anti-parallel tetramers of PCs based on the characteristics of band selection rule found in Raman and IR spectra. Equilibrium constants for the anti-parallel dimer (KD) and tetramer formation (KT) of PCs in Bz solution and in the pure liquid state were also determined using the Raman and IR data assuming chemical processes: 4PC ↔ 2(PC)2 ↔ (PC)4. |
| first_indexed | 2024-12-12T13:33:54Z |
| format | Article |
| id | doaj.art-0a60a94a48094fd6abe4c71c13bcdbee |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-12-12T13:33:54Z |
| publishDate | 2017-09-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-0a60a94a48094fd6abe4c71c13bcdbee2022-12-22T00:23:00ZengAIP Publishing LLCAIP Advances2158-32262017-09-0179095103095103-1510.1063/1.5002118014709ADVAnti-parallel dimer and tetramer formation of propylene carbonateAyana Tagawa0Tomoko Numata1Toshiyuki Shikata2Division of Natural Resources and Eco-materials, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, JapanHoriba Techno Service Co., Ltd., 2-6 Awaji-cho, Kanda, Chiyoda, Tokyo 101-0063, JapanDivision of Natural Resources and Eco-materials, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, JapanRaman scattering and infrared (IR) absorption spectra of enantiopure (R)-propylene carbonate ((R)PC) and racemic propylene carbonate (PC) were recorded at room temperature, 25 °C, in benzene (Bz) solution and in the pure liquid state to investigate the presence of dimers and other higher order intermolecular associations. (R)PC and PC both demonstrated a strong C=O stretching vibrational band. The band exhibited changes in its shape and resonance wavenumber highly dependent on the concentrations of PCs, whereas a difference between the chirality of (R)PC and PC had little influence. In an extremely dilute condition, doubly split bands were observed at 1807 and 1820 cm-1 in both Raman and IR spectra, which are assigned to the characteristic bands of isolated monomeric PCs. An additional band appeared at 1795 cm-1 in a dilute to concentrated regime, and its magnitude strengthened with increasing concentrations accompanied with slight increasing in the magnitude of 1807 cm-1 band in Raman spectra, while an increase in the magnitude of 1807 cm-1 band was clearly greater than that of 1795 cm-1 band in IR spectra. The spectrum changes at 1795 and 1807 cm-1 were attributed to characteristics of anti-parallel dimer formation of PCs caused by strong dipole-dipole interactions between C=O groups. Moreover, another additional signal was clearly observed at 1780-1790 cm-1 in a concentrated regime, and became the primary signal in the pure liquid state with slight increasing in the intensity of 1795 cm-1 band in Raman spectra. On the other hand, in IR spectra the observed increasing of 1780-1790 cm-1 band was much less than that of 1795 cm-1 band. These newly found spectrum changes in the concentrated regime are attributed to the formation of anti-parallel tetramers of PCs based on the characteristics of band selection rule found in Raman and IR spectra. Equilibrium constants for the anti-parallel dimer (KD) and tetramer formation (KT) of PCs in Bz solution and in the pure liquid state were also determined using the Raman and IR data assuming chemical processes: 4PC ↔ 2(PC)2 ↔ (PC)4.http://dx.doi.org/10.1063/1.5002118 |
| spellingShingle | Ayana Tagawa Tomoko Numata Toshiyuki Shikata Anti-parallel dimer and tetramer formation of propylene carbonate AIP Advances |
| title | Anti-parallel dimer and tetramer formation of propylene carbonate |
| title_full | Anti-parallel dimer and tetramer formation of propylene carbonate |
| title_fullStr | Anti-parallel dimer and tetramer formation of propylene carbonate |
| title_full_unstemmed | Anti-parallel dimer and tetramer formation of propylene carbonate |
| title_short | Anti-parallel dimer and tetramer formation of propylene carbonate |
| title_sort | anti parallel dimer and tetramer formation of propylene carbonate |
| url | http://dx.doi.org/10.1063/1.5002118 |
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