ASTM D2879-97

Standard Test Method for Vapor Pressure-Temperature Relationship and Initial Decomposition Temperature of Liquids by Isoteniscope

SCOPE
1.1 This test method covers the determination of the vapor pressure of pure liquids, the vapor pressure exerted by mixtures in a closed vessel at 40 + 5% ullage, and the initial thermal decomposition temperature of pure and mixed liquids. It is applicable to liquids that are compatible with borosilicate glass and that have a vapor pressure between 133 Pa (1.0 torr) and 101.3 kPa (760 torr) at the selected test temperatures. The test method is suitable for use over the range from ambient to 748 K. The temperature range may be extended to include temperatures below ambient provided a suitable constant-temperature bath for such temperatures is used.  Note 1-The isoteniscope is a constant-volume apparatus and results obtained with it on other than pure liquids differ from those obtained in a constant-pressure distillation.
1.2 Most petroleum products boil over a fairly wide temperature range, and this fact shall be recognized in discussion of their vapor pressures. Even an ideal mixture following Raoult's law will show a progressive decrease in vapor pressure as the lighter component is removed, and this is vastly accentuated in complex mixtures such as lubricating oils containing traces of dewaxing solvents, etc. Such a mixture may well exert a pressure in a closed vessel of as much as 100 times that calculated from its average composition, and it is the closed vessel which is simulated by the isoteniscope. For measurement of the apparent vapor pressure in open systems, Test Method D2878, is recommended.  
1.3 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. For specific hazard statements, see Notes 3, 4, and 5.  
1.4 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.

General Information

• Status: Historical
• Publication Date: 09-Apr-1997
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.L0.07 - Engineering Sciences of High Performance Fluids and Solids (Formally D02.1100)

Relations

• Replaced By: ASTM D2879-97(2002)e1 - Standard Test Method for Vapor Pressure-Temperature Relationship and Initial Decomposition Temperature of Liquids by Isoteniscope
• Effective Date: 10-Apr-1997
• Referred By: ASTM D7863-22 - Standard Guide for Evaluation of Convective Heat Transfer Coefficient of Liquids
• Effective Date: 10-Apr-1997
• Referred By: ASTM E2071-21 - Standard Practice for Calculating Heat of Vaporization or Sublimation from Vapor Pressure Data
• Effective Date: 10-Apr-1997
• Referred By: ASTM D7665-22 - Standard Guide for Evaluation of Biodegradable Heat Transfer Fluids
• Effective Date: 10-Apr-1997
• Referred By: ASTM D8046-21 - Standard Guide for Pumpability of Heat Transfer Fluids
• Effective Date: 10-Apr-1997
• Referred By: ASTM E1194-17 - Standard Test Method for Vapor Pressure
• Effective Date: 10-Apr-1997

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation:D2879–97
Standard Test Method for
Vapor Pressure-Temperature Relationship and Initial
1
Decomposition Temperature of Liquids by Isoteniscope
This standard is issued under the fixed designation D2879; 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 (ϵ) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of the vapor 2.1 ASTM Standards:
pressureofpureliquids,thevaporpressureexertedbymixtures D2878 Test Method for Estimating Apparent Vapor Pres-
2
in a closed vessel at 406 5% ullage, and the initial thermal sures and Molecular Weights of Lubricating Oils
decomposition temperature of pure and mixed liquids. It is E230 Temperature Electromotive Force (EMF) Tables for
3
applicabletoliquidsthatarecompatiblewithborosilicateglass Standardized Thermocouples
and that have a vapor pressure between 133 Pa (1.0 torr) and
3. Terminology
101.3 kPa (760 torr) at the selected test temperatures. The test
3.1 Definition of Term Specific to This Standard
method is suitable for use over the range from ambient to 748
K. The temperature range may be extended to include tem- 3.2 ullage—that percentage of a closed system which is
filled with vapor.
peratures below ambient provided a suitable constant-
temperature bath for such temperatures is used. 3.2.1 Discussion—Specifically,onFig.1,thatportionofthe
volumeoftheisoteniscopetotherightofpoint Awhichisfilled
NOTE 1—The isoteniscope is a constant-volume apparatus and results
with vapor.
obtained with it on other than pure liquids differ from those obtained in a
3.3 Symbols:
constant-pressure distillation.
1.2 Most petroleum products boil over a fairly wide tem-
perature range, and this fact shall be recognized in discussion
C = temperature, °C,
of their vapor pressures. Even an ideal mixture following K = temperature, K,
Raoult’s law will show a progressive decrease in vapor p = pressure, Pa or torr,
t = time, s,
pressureasthelightercomponentisremoved,andthisisvastly
P = experimentally measured total system pressure,
accentuated in complex mixtures such as lubricating oils e
P = partialpressureduetofixedgasesdissolvedinsample,
containing traces of dewaxing solvents, etc. Such a mixture a
P = corrected vapor pressure, Pa or torr.
c
may well exert a pressure in a closed vessel of as much as 100
timesthatcalculatedfromitsaveragecomposition,anditisthe K5 C1273.15 (1)
closed vessel which is simulated by the isoteniscope. For
4. Summary of Test Method
measurement of the apparent vapor pressure in open systems,
Test Method D2878D2878, is recommended. 4.1 Dissolved and entrained fixed gases are removed from
1.3 The values stated in SI units are to be regarded as the the sample in the isoteniscope by heating a thin layer of a
standard. The values in parentheses are for information only. sample at reduced pressure, removing in this process the
1.4 This standard does not purport to address all of the minimum amount of volatile constituents from the sample.
safety concerns, if any, associated with its use. It is the 4.2 The vapor pressure of the sample at selected tempera-
responsibility of the user of this standard to establish appro- tures is determined by balancing the pressure due to the vapor
priate safety and health practices and determine the applica- of the sample against a known pressure of an inert gas. The
bility of regulatory limitations prior to use. For specific hazard manometer section of the isoteniscope is used to determine
statements, see Note 3, Note 4, and Note 5. pressure equality.
4.3 The initial decomposition temperature is determined
from a plot of the logarithm of the vapor pressure versus the
reciprocal of absolute temperature. The initial decomposition
1
This test method is under the jurisdiction of ASTM Committee D-2 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.11 on Engineering Sciences of High Performance Fluids and Solids.
2
Current edition approved April 10, 1997. Published October 1997. Originally Annual Book of ASTM Standards, Vol 05.01.
3
published as D2879–70. Last previous edition D2879–96. Annual Book of ASTM Standards, Vol 14.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D2879–97
FIG. 1 Isoteniscope
temperature is taken as that temperature at wh
...