Compensation law again

Norwisz, J.; Musielak, T.

doi:10.1007/s10973-006-8139-4

Cited by 14 publications

(11 citation statements)

References 11 publications

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“…On the basis of the linear relationship obtained between ln A and E A , the average values of k iso = 4.17 × 10 −4 s −1 and T iso = 664.8 K were calculated, respectively. The graphical representation of the dependence between the values of E A and ΔS / = for all the polymer composites studied clearly shows the good linear relationship between them Figure (6).…”

Section: Resultsmentioning

confidence: 77%

“…If the kinetic studies are carried out on similar compounds and with a correctly chosen mechanism function f (α), a linear relationship between the logarithm of the pre-exponential factors and activation energies exists, known as the kinetic compensation effect (KCE), isokinetic effect, or theta rule [5][6][7][8]. Such a correlation was firstly reported in 1925 by Constable [9], in connection with his catalytic studies.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Turmanova

Genieva

Vlaev

2011

Journal of Thermodynamics

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Studying the nonisothermal kinetics of degradation of rice husks in air or nitrogen atmosphere, polypropylene and tetrafluoroethylene-ethylene copolymer filled with different quantities of rice husks flour or the products of its thermal degradation, namely "white" or "black" rice husks ash, a linear dependence was observed between the ln A and E A , known as the kinetic compensation effect or theta rule. A linear relationship was also established between E A and the change of the entropy ΔS / = for the formation of the activated complex from the reagents. These dependences are related to the assumption of identical kinetic mechanisms of thermal degradation of the composites studied. The negative values of ΔS / = obtained show that the activated complex is a "more organized" structure than the initial reactants and that these reactions may be classified as "slow" ones. It may be concluded that the products of the thermal degradation of rice husks in a fluidized bed reactor can successfully replace the more expensive synthetic fillers to obtain different polymer composites. These polymer composites can lead to the futuristic "organic-inorganic hybrid materials" with specific properties.

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Section: Resultsmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Turmanova

Genieva

Vlaev

2011

Journal of Thermodynamics

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“…In many thermodynamic analyses of chemical reactions/ processes, it has been experimentally demonstrated that there are linear dependencies for the standard thermodynamic function, named the EEC compensation effect (enthalpy-entropy compensation) [ (Sharp 2001;Marco and Linert 2002;Ryde 2014;Olsson et al 2008;Dutronc et al 2014;Klebe 2015) KCE (Norwisz and Musielak 2007;Lvov 2007)]. According to Starikov, the relevant entry is expressed as follows (Starikov 2014): where the slope coefficient is constant and is named the isokinetic temperature, and the intercept ∆H iso which is part of enthalpy, is replaceable in isoentropic conditions (∆S = 0).…”

Section: Introductionmentioning

confidence: 99%

Enthalpy–entropy compensation for isosteric state adsorption at near ambient temperatures

Mianowski

Urbańczyk

2017

Adsorption

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List of symbols AbstractThe adsorption process at near ambient temperatures indicated that the EEC (enthalpy-entropy compensation) is affected by three basic thermodynamic values: ∆H, ∆S and T. The consequence is that it is possible to determine an isosteric straight (symbol H − S) without experimental studies based on the slope coefficient T iso , which is the constant arising from the expected temperature range (about 0-60 °C). Therefore, EEC curves can be obtained by appropriate modification of the temperature range. In the case of entropy of adsorption, the decisive influence is the entropy of gas. For visualization and characterization of this impact, we proposed resolute pointer µ (Eq. 25), through which it is observed that for small values of the equilibrium vapor pressure, as P → 0, there are significant deviations from the isosteric straight H − S. The case where P → P 0 followed a gradual grouping of experimental data in accordance with the relationship with H − S. We used the three-parameter equation for exothermic processes. For the extrapolated conditions, the so-called point of zero adsorption represented the enthalpy and entropy of adsorption, whose values are analogous to previous results in the literature, which can be considered an appropriate analytical method to determine these two thermodynamic values.

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“…Kinetic studies carried out on similar compounds with a correctly chosen mechanism function f (α) (α is the weight fraction of material decomposed at temperature T and time t) exhibit a linear relationship between the logarithm of the preexponential factors and activation energies known as the compensation effect [1][2][3][4][5]. Several theories and explanations for such compensation behavior have been put forth [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Normally, two types of reaction models, the first order f (α) 1 = (1 − α) and the second order f (α) 2 = (1 − α) 2 , are used for the thermal degradation studies of polymers.…”

Section: Introductionmentioning

confidence: 99%

Enthalpy-Entropy Compensation in Polyester Degradation Reactions

Al‐Mulla

2012

International Journal of Chemical Engineering

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In an earlier work the author had studied the degradation kinetics of polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT) under nonisothermal conditions in air and N 2 at heating rates of 5, 10, 15, and 20• C/min. In this paper the kinetic degradation parameters of PET, PTT, and PBT were estimated using the CoatsRedfern method for two different weight loss regions ranging from 2-8% (Zone I) and 8-40% (Zone II). A comparative analysis of the enthalpy-entropy compensation effect for these polyesters in air and N 2 is presented. A linear relationship was found to exist between entropy and enthalpy values. The following criteria were applied to establish an enthalpy-entropy compensation effect and to check the presence of an isokinetic temperature: (a) Exner's plot of log k 3T1 versus log k 3T2 , and (b) Krug et al. linear regression of ΔH versus ΔG. By the use of the latter two methods, varying isokinetic temperatures were obtained. These temperatures were not in the range of the experimental work conducted, indicating that these systems do not display compensation phenomena.

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Compensation law again

Cited by 14 publications

References 11 publications

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Enthalpy–entropy compensation for isosteric state adsorption at near ambient temperatures

Enthalpy-Entropy Compensation in Polyester Degradation Reactions

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