On the compensation effect

Agrawal, Ravindra K.

doi:10.1007/bf01913888

Cited by 130 publications

(46 citation statements)

References 34 publications

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“…It has correlation coefficients greater than 0.99 for all the polyesters degraded in air and N 2 . In some systems, [24,25] it has been observed that the activation energy varies under different measuring conditions. It is also found that the variation in activation energy is accompanied by a change in A that is; a large activation energy is accompanied by a large preexponential factor and vice versa, a phenomena often referred to as compensation effect.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%

Enthalpy-Entropy Compensation in Polyester Degradation Reactions

Al‐Mulla

2012

International Journal of Chemical Engineering

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“…Agrawal [15,16] has objected the postulation of compensation effect occurring in cellulosic materials, in contradiction to the Chornet and Roy's work (1980, op., cit). The argument was grounded on the basis of theoretical analysis; no further experimental evidence has however been established.…”

Section: Resultsmentioning

confidence: 92%

Compensation Effects In The Non-isothermal Pyrolysis Of Wood

Lim¹,

Linchew²

2005

Fire Safety Science - Proceedings of the Eigth International Sy

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A considerable variation exists in the kinetics constants that were derived using Arrhenius equation in the study of the reaction kinetics for wood pyrolysis. It is of interest to evaluate whether compensation behaviours that usually associate with a series of related reactions might have contributed to the observed variations in the nonisothermal pyrolysis kinetics. The study of the compensation effects was intended to seek a logical explanation for the observed variations of the apparently large and differed values of activation energy and pre-exponential factors. Statistical regression analyses were performed to correlate the Arrhenius parameters derived from the non-isothermal Thermogravimetry Analysis (TGA) data. To gain an insight on the competing reactions so as to expound the varied kinetic data, these transition kinetics were also analyzed for exothermic transition using Differential Scanning Calorimetry (DSC) for heat of pyrolysis. This study showed that compensation effect existed, but found that the enthalpy of transition held a stronger proposition on the transition kinetics. KEYWORDS

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“…In the coordinate of lnk-1/T, the straight lines corresponding to different kinetic parameters (A, E) which satisfying KCE relation have a common interaction point (1/T iso , lnk iso ). Agrawal [9] claimed a criterion to recognize the KCE relation, i.e. KCE relation exists only if the plots lnk~1/T display concurrence at a single point.…”

Section: On the Criterion To Distinguish Between True And False Kinetmentioning

confidence: 99%

Kinetic Compensation Effect In The Thermal Decomposition Of Biomass In Air Atmosphere

Liu¹,

Wang²,

Fan³

2003

Fire Safety Science - Proceedings of the Seventh International

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The wood and leaf samples of eight species are examined by non-isothermal means to determine the mass loss kinetics of the thermal decomposition with linear temperature programming in air atmosphere. A simple kinetic description is developed based on the experimental results and integral analysis method. In the model, the mass loss process consists of three steps. The first step corresponds to the water evaporation, and the subsequent two mass loss steps are mainly due to two major pseudo components. The two pseudo components decompose respectively at two separate temperature regions. Under this kinetic scheme, the kinetic compensation effect is analyzed and it is found that the kinetic parameters E and A resulted from the variation of the species and the variation of model functions exhibit kinetic compensation effect. Quantitative and statistical criterion to distinguish between real and false compensation effect is discussed in detail.

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On the compensation effect

Cited by 130 publications

References 34 publications

Enthalpy-Entropy Compensation in Polyester Degradation Reactions

Enthalpy-Entropy Compensation in Polyester Degradation Reactions

Compensation Effects In The Non-isothermal Pyrolysis Of Wood

Kinetic Compensation Effect In The Thermal Decomposition Of Biomass In Air Atmosphere

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