Low-Temperature Heat Capacity of L- and DL-Phenylglycines Научная публикация
Журнал |
Journal of Thermal Analysis and Calorimetry
ISSN: 1388-6150 , E-ISSN: 1572-8943 |
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Вых. Данные | Год: 2012, Том: 108, Номер: 3, Страницы: 1311-1316 Страниц : 6 DOI: 10.1007/s10973-009-0665-4 | ||||||
Ключевые слова | Adiabatic calorimetry L-phenylglycine DL-phenylglycine Heat capacity Molecular crystals Chiral/racemic counterparts | ||||||
Авторы |
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Организации |
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Реферат:
Heat capacity of crystalline L- and DL-phenylglycines was measured in the temperature range from 6 to 305 K. For L-phenylglycine, no anomalies in the C p (T) dependence were observed. For DL-phenylglycine, however, an anomaly in the temperature range 50–75 K with a maximum at about 60 K was registered. The enthalpy and the entropy changes corresponding to this anomaly were estimated as 20 J mol−1 and 0.33 J K−1 mol−1, respectively. In the temperature range 205–225 K, an unusually large dispersion of the experimental points and a small change in the slope of the C p (T) curve were noticed. Thermodynamic functions for L- and DL-phenylglycines in the temperature range 0–305 K were calculated. At 298.15 K, the values of heat capacity, entropy, and enthalpy are equal to 179.1, 195.3 J K−1 mol−1, and 28590 J mol−1 for L-phenylglycine and 177.7, 196.3 J K−1 mol−1 and 28570 J mol−1 for DL-phenylglycine. For both L- and DL-phenylglycine, the C p (T) at very low temperatures does not follow the Debye law C – T 3 . The heat capacity C p (T) is slightly higher for L-phenylglycine, than for the racemic DL-crystal, with the exception of the phase transition region. The difference is smaller than was observed previously for the L-/DL-cysteines, and considerably smaller, than that for L-/DL- serines.
Библиографическая ссылка:
Paukov I.E.
, Kovalevskaya Y.A.
, Boldyreva E.V.
Low-Temperature Heat Capacity of L- and DL-Phenylglycines
Journal of Thermal Analysis and Calorimetry. 2012. V.108. N3. P.1311-1316. DOI: 10.1007/s10973-009-0665-4 WOS Scopus РИНЦ
Low-Temperature Heat Capacity of L- and DL-Phenylglycines
Journal of Thermal Analysis and Calorimetry. 2012. V.108. N3. P.1311-1316. DOI: 10.1007/s10973-009-0665-4 WOS Scopus РИНЦ
Даты:
Поступила в редакцию: | 18 мар. 2009 г. |
Принята к публикации: | 17 дек. 2009 г. |
Опубликована online: | 3 нояб. 2010 г. |
Опубликована в печати: | 1 июн. 2012 г. |
Идентификаторы БД:
Web of science | WOS:000304621000063 |
Scopus | 2-s2.0-84877079439 |
РИНЦ | 23959516 |
Chemical Abstracts | 2012:763873 CAN |
Chemical Abstracts (print) | 157:146116 |
OpenAlex | W2041332689 |