Standard Test Method for Reaction Induction Time by Thermal Analysis

SIGNIFICANCE AND USE
This test method measures the time to extrapolated onset of an exothermic reaction under constant temperature (isothermal) conditions for reactions which have an induction period, for example, those which are catalytic or autocatalytic in nature or which contain reaction inhibitors.
The RIT determined by this test method is to be considered an index measurement that is useful for comparing one material to another at the test temperature of interest and in the same apparatus type only.
This test method is a useful adjunct to dynamic thermal tests, such as Test Method E 537, which are performed under conditions in which the sample temperature is increased continuously at constant rate. Results obtained under dynamic test conditions may result in higher estimates of temperature at which an exothermic reaction initiates because the detected onset temperature is dependent upon the heating rate and because dynamic methods allow insufficient time for autocatalytic reactions to measurably affect the onset temperature.
RIT values determined under a series of isothermal test conditions may be plotted as their logarithm versus the reciprocal of the absolute temperature to produce a plot, the slope of which is proportional to the activation energy of the reaction as described in Test Method E 2070.
This test method may be used in research and development, manufacturing, process and quality control, and regulatory compliance.
This test method is similar to that for Oxidation Induction Time (OIT) (for example, Specification D 3350 and Test Methods D 3895, D 4565, D 5483, D 6186, and E 1858) where the time to the oxidation reaction under isothermal test conditions is measured. The OIT test method measures the presence of antioxidant packages and is a relative measurement of a material’resistance to oxidation.
SCOPE
1.1 This test method describes the measurement of Reaction Induction Time (RIT) of chemical materials that undergo exothermic reactions with an induction period. The techniques and apparatus described may be used for solids, liquids, or slurries of chemical substances. The temperature range covered by this test method is typically from ambient to 400C. This range may be extended depending upon the apparatus used.
1.2 The RIT is a relative index value, not an absolute thermodynamic property. As an index value, the RIT value may change depending upon experimental conditions. A comparison of RIT values may be made only for materials tested under similar conditions of apparatus, specimen size, and so forth. Furthermore, the RIT value may not predict behavior of large quantities of material.
1.3 The RIT shall not be used by itself to establish a safe operating temperature. It may be used in conjunction with other test methods (for example, E 487, E 537, and E 1981 as part of a hazard analysis of a particular operation.
1.4 This test method may be used for RIT values greater than 15 min (as relative imprecision increases at shorter periods).
1.5 This test method is used to study catalytic and autocatalytic reactions. These reactions depend upon time as well as temperature. Such reactions are often studied by fixing one experimental parameter (that is, time or temperature) and then measuring the other parameter (that is, temperature or time). This test method measures time to reaction onset detection under isothermal conditions. It is related to Test Method E 487 that measures detected reaction onset temperature under constant time conditions
1.6 SI units are the standard.
1.7 There is no ISO standard equivalent to this test method.
1.8 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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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Publication Date
09-Jul-2003
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ASTM E2046-03 - Standard Test Method for Reaction Induction Time by Thermal Analysis
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E2046–03
Standard Test Method for
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Reaction Induction Time by Thermal Analysis
This standard is issued under the fixed designation E 2046; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method describes the measurement of Reaction 2.1 ASTM Standards:
Induction Time (RIT) of chemical materials that undergo D 3350 Specification for Polyethylene Plastics Pipe and
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exothermic reactions with an induction period. The techniques Fittings Materials
and apparatus described may be used for solids, liquids, or D 3895 Test Method for Oxidative-Induction Time of Poly-
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slurriesofchemicalsubstances.Thetemperaturerangecovered olefins by Differential Scanning Calorimetry
by this test method is typically from ambient to 400°C. This D 4565 Test Methods for Physical and Environmental Per-
range may be extended depending upon the apparatus used. formance Properties of Insulations and Jackets for Tele-
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1.2 The RIT is a relative index value, not an absolute communications Wire and Cable
thermodynamicproperty.Asanindexvalue,theRITvaluemay D 5483 Test Method for Oxidation Induction Time of Lu-
change depending upon experimental conditions. A compari- bricating Greases by Pressure Differential Scanning Calo-
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son of RITvalues may be made only for materials tested under rimetry
similar conditions of apparatus, specimen size, and so forth. D 6186 Test Method for Oxidation Induction Time of Lu-
Furthermore, the RIT value may not predict behavior of large bricating Oils by Pressure Differential Scanning Calorim-
quantities of material. etry
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1.3 The RIT shall not be used by itself to establish a safe E 473 Terminology Relating to Thermal Analysis
operating temperature. It may be used in conjunction with E 487 Test Method for Constant-Temperature Stability of
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other test methods (for example, E 487, E 537, and E 1981 as Chemical Materials
part of a hazard analysis of a particular operation. E 537 Test Method for Assessing the Thermal Stability of
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1.4 This test method may be used for RIT values greater Chemicals by Methods of Differential Thermal Analysis
than 15 min (as relative imprecision increases at shorter E 967 Practice for Temperature Calibration of Differential
periods). Scanning Calorimeters and Differential Thermal Analyz-
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1.5 This test method is used to study catalytic and autocata- ers
lytic reactions. These reactions depend upon time as well as E 968 Practice for Heat Flow Calibration of Differential
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temperature. Such reactions are often studied by fixing one Scanning Calorimeters
experimental parameter (that is, time or temperature) and then E 1445 Terminology Relating to Hazardous Potential of
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measuring the other parameter (that is, temperature or time). Chemicals
This test method measures time to reaction onset detection E 1858 Test Method for Determining Oxidative Induction
under isothermal conditions. It is related to Test Method E 487 Time of Hydrocarbons by Differential Scanning Calorim-
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that measures detected reaction onset temperature under con- etry
stant time conditions E 1860 Test Method for Elapsed Time Calibration of Ther-
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1.6 SI units are the standard. mal Analyzers
1.7 There is no ISO standard equivalent to this test method. E 1981 Guide for Assessing the Thermal Stability of Mate-
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1.8 This standard does not purport to address all of the rials by Method of Accelerating Rate Calorimetry
safety concerns, if any, associated with its use. It is the E 2070 Test Method for Kinetic Parameters by Differential
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responsibility of the user of this standard to consult and Scanning Calorimetry Using Isothermal Methods
establish appropriate safety and health practices and deter-
3. Terminology
mine the applicability of regulatory limitations prior to use.
3.1 The specialized terms used in this test method are
described in Terminologies E 473 and E 1445.
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This test method is under the jurisdiction ofASTM Committee E27 on Hazard
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Potential of Chemicals and is the direct responsibility of Subcommittee E27.02 on Annual Book of ASTM Standards, Vol 08.02.
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Thermal Stability and Condensed Phases. Annual Book of ASTM Standards, Vol 10.02.
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Current edition approved July 10, 2003. Published September 2003. Originally Annual Book of ASTM Standards, Vol 05.03.
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approved in 1999. Last previous edition approved in 1999 as E 2046 – 99. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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