Activation Parameters of Supercritical and Gas-Phase β-Pinene Thermal Isomerization Научная публикация
| Журнал |
Russian Journal of Physical Chemistry A
ISSN: 0036-0244 , E-ISSN: 1531-863X |
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| Вых. Данные | Год: 2011, Том: 85, Номер: 9, Страницы: 1505-1515 Страниц : 11 DOI: 10.1134/S0036024411090068 | ||||||
| Ключевые слова | β-Pinene thermal isomerization, activation parameters, enthalpy-entropy compensation effect, isokinetic relationship, pressure dependence | ||||||
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Реферат:
New data on enthalpy and entropy contributions to the energy barrier of β-pinene thermal isomerization were obtained. The rate of β-pinene conversion is higher in supercritical EtOH (P = 120 atm) than in the gas phase (P ≤ 1 atm, without solvent, or for inert carrier gas N2) at equal temperatures. The highest activation energy E Σ of total β-pinene conversion is also observed in reactions in the supercritical (sc) condition. Activation parameters ΔH Σ # , ΔS Σ # , and ΔG Σ # depend strongly on the reaction pressure. Thus, at P ≤ 1 atm (gas-phase reaction) the values of ΔS Σ # are negative, while at sc conditions at P = 120 atm is positive. The linear dependences lnk Σ0 − E Σ and ΔS Σ # − ΔS Σ # indicate an isokinetic relation (IKR) and enthalpy-entropy compensation effect (EEC). The isokinetic temperature was calculated (T iso = 605.5 ± 22.7 K). It was shown that elevation of temperature reduces the value of ΔG Σ # (T) upon sc thermolysis only, whereas in all gas-phase reactions ΔG Σ # (T) increases. At equal reaction temperatures, the greatest values of K eq # (T) proved to be typical for thermolysis in sc-EtOH. We hypothesize that the rate of total β-pinene conversion increases dramatically due to a considerable shift in equilibrium toward higher concentrations of activated complex y TS # . A detailed analysis of activation parameters shows that the IKR and EEC coincide, evidence of a common mechanism of β-pinene conversion observed under different reaction conditions, including thermolysis in sc-EtOH.
Библиографическая ссылка:
Chibiryaev A.M.
, Ermakova A.
, Kozhevnikov I.V.
Activation Parameters of Supercritical and Gas-Phase β-Pinene Thermal Isomerization
Russian Journal of Physical Chemistry A. 2011. V.85. N9. P.1505-1515. DOI: 10.1134/S0036024411090068 WOS Scopus РИНЦ CAPlusCA OpenAlex
Activation Parameters of Supercritical and Gas-Phase β-Pinene Thermal Isomerization
Russian Journal of Physical Chemistry A. 2011. V.85. N9. P.1505-1515. DOI: 10.1134/S0036024411090068 WOS Scopus РИНЦ CAPlusCA OpenAlex
Оригинальная:
Чибиряев А.М.
, Ермакова А.
, Кожевников И.В.
Параметры активации термической изомеризации β--пинена в сверхкритических и газофазных условиях
Журнал физической химии. 2011. Т.85. №9. С.1621-1632. РИНЦ
Параметры активации термической изомеризации β--пинена в сверхкритических и газофазных условиях
Журнал физической химии. 2011. Т.85. №9. С.1621-1632. РИНЦ
Даты:
| Поступила в редакцию: | 6 сент. 2010 г. |
| Опубликована online: | 30 июл. 2011 г. |
| Опубликована в печати: | 1 сент. 2011 г. |
Идентификаторы БД:
| Web of science: | WOS:000293294200005 |
| Scopus: | 2-s2.0-80051591647 |
| РИНЦ: | 18058583 |
| Chemical Abstracts: | 2011:947711 |
| Chemical Abstracts (print): | 155:509572 |
| OpenAlex: | W1979376588 |