ASTM E698-05
(Test Method)Standard Test Method for Arrhenius Kinetic Constants for Thermally Unstable Materials
Standard Test Method for Arrhenius Kinetic Constants for Thermally Unstable Materials
SIGNIFICANCE AND USE
The Arrhenius parameters combined with the general rate law and the reaction enthalpy can be used for the determination of thermal explosion hazards (1).3
SCOPE
1.1 This method covers the determination of the overall kinetic parameters for exothermic reactions using the Flynn/Wall/Ozawa method and differential scanning calorimetry.
1.2 This technique is applicable to reactions whose behavior can be described by the Arrhenius equation and the general rate law.
1.3 LimitationsThere are cases where this technique is not applicable. Limitations may be indicated by curves departing from a straight line (see ) or the isothermal aging test not closely agreeing with the results predicted by the calculated kinetic values. In particular, this method is not applicable to reactions that are partially inhibited. The technique may not work with reactions that include simultaneous or consecutive reaction steps. This method may not apply to materials that undergo phase transitions if the reaction rate is significant at the transition temperature.
1.4 SI units are the standard.
This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
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Designation:E698–05
Standard Test Method for
Arrhenius Kinetic Constants for Thermally Unstable
Materials Using Differential Scanning Calorimetry and the
1
Flynn/Wall/Ozawa Method
This standard is issued under the fixed designation E698; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The kinetics of exothermic reactions are important in assessing the potential of materials and
systems for thermal explosion. This test method provides a means for determining Arrhenius
activationenergiesandpre-exponentialfactorsusingdifferentialthermalmethods.Thistestmethodis
one of several test methods being developed byASTM Committee E27 for chemical reactions. This
test method is to be used in conjunction with other tests to characterize the hazard potential of
chemicals.
1. Scope 2. Referenced Documents
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1.1 This test method covers the determination of the overall 2.1 ASTM Standards:
kinetic parameters for exothermic reactions using the Flynn/ E473 Terminology Relating to Thermal Analysis and Rhe-
Wall/Ozawa method and differential scanning calorimetry. ology
1.2 Thistechniqueisapplicabletoreactionswhosebehavior E691 Practice for Conducting an Interlaboratory Study to
canbedescribedbytheArrheniusequationandthegeneralrate Determine the Precision of a Test Method
law. E968 Practice for Heat Flow Calibration of Differential
1.3 Limitations—Therearecaseswherethistechniqueisnot Scanning Calorimeters
applicable. Limitations may be indicated by curves departing E1142 Terminology Relating to Thermophysical Properties
from a straight line (see 11.2) or the isothermal aging test not E1445 TerminologyRelatingtoHazardPotentialofChemi-
closely agreeing with the results predicted by the calculated cals
kinetic values. In particular, this test method is not applicable E1860 Test Method for Elapsed Time Calibration of Ther-
to reactions that are partially inhibited. The technique may not mal Analyzers
work with reactions that include simultaneous or consecutive E1970 Practice for Statistical Treatment of Thermoanalyti-
reactionsteps.Thistestmethodmaynotapplytomaterialsthat cal Data
undergo phase transitions if the reaction rate is significant at
3. Terminology
the transition temperature.
3.1 Technical terms used in this test method are defined in
1.4 SI units are the standard.
1.5 This standard may involve hazardous materials, opera- Terminologies E473, E1142, and E1445.
tions, and equipment. This standard does not purport to
4. Summary of Test Method
address all of the safety concerns, if any, associated with its
4.1 Asampleisplacedinasuitablecontainerandpositioned
use. It is the responsibility of the user of this standard to
in a differential scanning calorimeter (DSC).
establish appropriate safety and health practices and deter-
4.2 The sample equipment temperature is increased at a
mine the applicability of regulatory limitations prior to use.
linear rate and any exothermic reaction peaks recorded.
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This test method is under the jurisdiction ofASTM Committee E27 on Hazard
Potential of Chemicals and is the direct responsibility of Subcommittee E27.02 on
2
Thermal Stability and Condensed Phases. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2005. Published April 2005. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1979. Last previous edition approved in 2004 as E698–01. DOI: Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
10.1520/E0698-05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E698–05
4.3 Steps 4.1 and 4.2 are repeated for several heating rates 6.3 Containers (pans, crucibles, vials, etc), which are inert
-1
in the range from 1 to 10 K min . to the specimen and reference materials and which are suitable
4.4 Temperatures at which the reaction peak maxima occur structural shape and integrity to contain the specimen and
are plotted as a function of their respective heating rates. reference in accordance with the specific requirements of this
4.5 Kinetic values calculated from the peak temperature- test method.
heating rate relationship are used to predict a reaction half-life 6.4 A balance, with a capacity of at least 100 mg, to weigh
at a selected temperature. specimens and/or containers (pans, crucibles, vials, etc) to
4.6 A sample is aged at the selected temperature for the within 10 µg.
predicted half-life time. 6.5 Auxilia
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