ASTM E2071-2000(2005) Standard Practice for Calculating Heat of Vaporization or Sublimation from Vapor Pressure Data《从蒸气压力数据中计算汽化热或蒸馏热的标准规程》.pdf
《ASTM E2071-2000(2005) Standard Practice for Calculating Heat of Vaporization or Sublimation from Vapor Pressure Data《从蒸气压力数据中计算汽化热或蒸馏热的标准规程》.pdf》由会员分享,可在线阅读,更多相关《ASTM E2071-2000(2005) Standard Practice for Calculating Heat of Vaporization or Sublimation from Vapor Pressure Data《从蒸气压力数据中计算汽化热或蒸馏热的标准规程》.pdf(4页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: E 2071 00 (Reapproved 2005)Standard Practice forCalculating Heat of Vaporization or Sublimation from VaporPressure Data1This standard is issued under the fixed designation E 2071; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes the calculation of the heat ofvaporization of a liquid or the heat of s
3、ublimation of a solidfrom measured vapor pressure data. It is applicable to pureliquids, azeotropes, pure solids, and homogenous solid solu-tions over the temperature range for which the vapor pressureequation fitted to the measured data is applicable.NOTE 1This practice is generally not applicable
4、to liquid mixtures.For a pure liquid or azeotrope, composition does not change uponvaporization so that the integral heat of vaporization is identical to thedifferential heat of vaporization. Non-azeotropic liquid mixtures changecomposition upon vaporizing. Heat of vaporization data computed fromthi
5、s practice for a liquid mixture are valid only as an approximation to themixture differential heat of vaporization; it is not a valid approximation tothe mixture integral heat of vaporization.1.2 SI values are standard.1.3 This standard does not purport to address all of thesafety concerns, if any,
6、associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 There is no ISO standard equivalent to this practice.2. Referenced Documents2.1 ASTM Standar
7、ds:2D 2879 Standard Test Method for Vapor Pressure-Temperature Relationship and Initial Decomposition Tem-perature of Liquids by IsoteniscopeE 1142 Standard Terminology Relating to ThermophysicalPropertiesE 1194 Standard Test Method for Vapor PressureE 1719 Standard Test Method for Vapor Pressure of
8、 Liquidsby EbulliometryE 1782 Standard Test Method for Determining Vapor Pres-sure by Thermal Analysis3. Terminology3.1 Symbols:3.1.1 A, B, CAntoine vapor pressure equation constants(log10, kPa, K), Antoine vapor pressure equation:log10P 5 A 2 B/T 1 C!3.1.2 Pvapor pressure, kPa.3.1.3 Pccritical pres
9、sure, kPa.3.1.4 Prreduced pressure = P/Pc.3.1.5 Tabsolute temperature, K.3.1.6 Tccritical temperature, K.3.1.7 Trreduced temperature = T/Tc.3.1.8 Vmolar volume, cm3/mol.3.1.9 Rgas constant, 8.31433 J/mol-K; 8314330. kPa-cm3/mol-K.3.1.10 DHVheat of vaporization, J/mol.3.1.11 DZVdifference in compress
10、ibility factor (Z = PV/RT) upon vaporization. Clapeyron equation:DHV52RDZVdlnP!/d1/T!#3.1.11.1 DiscussionThe subscript “V” will be usedthroughout this practice to designate the vaporization of aliquid. If the vapor pressure data were measured for a solid,substitute the subscript “S” for the sublimat
11、ion of a solid.3.2 Definitions:3.2.1 Specialized terms used in this practice are defined inTerminology E 1142.3.2.2 sublimationtransition from a solid phase to a gas-eous phase.3.2.3 vaporizationtransition from a liquid phase to agaseous phase.4. Summary of Practice4.1 Vapor pressure data are measur
12、ed by other referencedASTM Standards and then correlated with the Antoine equa-tion. The heat of vaporization or sublimation is computed at thedesired temperature from the vapor-pressure temperature de-rivative from the fitted Antoine equation by use of theClapeyron equation (1)3. In the Clapeyron e
13、quation, DZVis1This practice is under the jurisdiction of Committee E37 on Thermal Measure-ments and is the direct responsibility of Subcommittee E37.01 on Test Methods andRecommended Practices.Current edition approved March 1, 2005. Published April 2005. Originallyapproved in 2000. Last previous ed
14、ition approved in 2000 as E 207100.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The boldface numbers give
15、n in parentheses refer to a list of references at theend of the text.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.determined by either the Clausius-Clapeyron (2) approxima-tion DZV5 1! or the Haggenmacher(3) approximationDZV5 $1Pr
16、/Tr!3#%1/2! .4.2 An example calculation is given in Annex A1.5. Significance and Use5.1 If the heat of vaporization or sublimation is absorbed orliberated in a process at constant pressure, it is called enthalpyof vaporization or sublimation. Enthalpy of vaporization orsublimation is a fundamental t
17、hermodynamic property of aliquid or solid. It is an important quantity in the design of heatexchangers and other chemical process units. Enthalpy ofvaporization is also used to calculate solubility parameters(4).5.2 This practice may be used in research, regulatorycompliance, and quality assurance a
18、pplications.6. Experimental Vapor Pressure Data6.1 Vapor pressure data are measured by Test MethodsD 2879, E 1194, E 1719,orE 1782. Note the safety precau-tions contained in the test method used.6.1.1 Vapor pressure data from other reliable sources, forexample, peer-review technical journals, may be
19、 used. Thesource of the vapor pressure data must be noted.6.2 The measured vapor pressure data are fitted to anAntoine vapor pressure equation. See 10.3 in Test MethodE 1719 for details on least-squares regression of vapor pressuredata.7. Calculation7.1 At each temperature of interest, calculate the
20、 vaporpressure from the Antoine equation and calculate the vapor-pressure temperature derivative from the fitted Antoine equa-tion constants from:dlnP!/d1/T!# 522.3025851BT2/T 1 C!2#7.2 Calculate an approximation to DZVat each temperature.7.2.1 The Clausius-Clapeyron approximation to DZVis:DZV 1.07.
21、2.2 The Haggenmacher approximation to DZVis:DZV5 $1Pr/Tr!3#%12NOTE 2The Clausius-Clapyeron approximation is generally used forsolids and for liquids at low Tr. The Haggenmacher approximation isgenerally used for liquids up to Tr 0.75.7.2.3 If equation of state (Z) data are available for both thecond
22、ensed and gaseous phases, DZVmay be calculated directlyfrom the equation of state data.7.3 Calculate the heat of vaporization or heat of sublimationat each temperature from the Clapeyron equation:DHV52RDZVdlnP!/d1/T!#8. Report8.1 Report the following information:8.1.1 The Test Method and source of t
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