1、Designation: D 6875 03Standard Test Method forSolidification Point of Industrial Organic Chemicals byThermistor1This standard is issued under the fixed designation D 6875; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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 test method covers a general procedure for deter-mining the solidification point of most organic chemicalshavin
3、g appreciable heats of fusion and solidification pointsbetween 4 and 41C.NOTE 1Other test methods for determining freeze point and solidifi-cation point of aromatic hydrocarbons include Test Methods D 852,D 1015, D 1016, D 1493, D 3799, D 4493, and D 6269.1.2 This test method is applicable to relati
4、vely pure com-pounds only. Solidification point depression is dependent onimpurity concentrations.1.3 The following applies to all specified limits in this testmethod: for purposes of determining conformance with appli-cable specifications using this test method, an observed valueor a calculated val
5、ue shall be rounded off “to the nearest unit”in the last right hand digit used in expressing the specificationlimit, in accordance with the “rounding-off method” of PracticeE 29.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
6、ibility 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. For a specifichazard statement, see Section 8, Hazards.2. Referenced Documents2.1 ASTM Standards:D 852 Test Method for Solidification Po
7、int of Benzene2D 1015 Test Method for Freezing Point of High-PurityHydrocarbons3D 1016 Test Method for Purity of Hydrocarbons fromFreezing Points3D 1493 Test Method for Solidification Point of IndustrialOrganic Chemicals2D 3437 Practice for Sampling and Handling Liquid CyclicProducts2D 3438 Practice
8、 for Sampling and Handling Naphthalene,Maleic Anhydride, and Phthalic Anhydride2D 3799 Test Method for Purity of Styrene by Freezing PointMethod2D 3852 Practice for Sampling and Handling Phenol,Cresols, and Cresylic Acid2D 4297 Practice for Sampling and Handling Bisphenol A(4,4-Isoproplyidenedipheno
9、l)2D 4493 Test Method for Solidification Point of Bisphenol A(4,4-Isoproplyidenediphenol)2D 6269 Test Method for Solidification Point of p-Xylene2E 29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications42.2 Other Documents:OSHA Regulations, 29 CRFR, paragra
10、phs 1910.1000 and1910.120053. Terminology3.1 Definitions:3.1.1 solidification point, nan empirical constant definedas the temperature at which the liquid phase of a substance isin approximate equilibrium with a relatively small portion ofthe solid phase.3.1.1.1 DiscussionSolidification point as dist
11、inguishedfrom freezing point is described in Test Method D 1015. Aninterpretation of mole percent in terms of freezing point isgiven in Test Method D 1016.4. Summary of Test Method4.1 The solidification point is measured by noting themaximum temperature reached during a cooling cycle after theappear
12、ance of a solid phase.5. Significance and Use5.1 This test method may be used for process control duringthe manufacture of organic chemicals described in Section 1,for setting specifications, for development and research work,and to determine if contamination was introduced duringshipment.1This test
13、 method is under the jurisdiction of ASTM Committee D16 onPackaging and is the direct responsibility of Subcommittee D16.04 on InstrumentalAnalysis.Current edition approved Feb. 10, 2003. Published April 2003.2Annual Book of ASTM Standards, Vol 06.04.3Annual Book of ASTM Standards, Vol 05.01.4Annual
14、 Book of ASTM Standards, Vol 14.02.5Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6
15、.1 Ohmmeter, capable of measuring resistance to the near-est 0.1 ohm in the range of 1000 to 10 000 ohms with directtemperature readout.66.2 Specimen Container, thick walled test tube with 18 mmoutside diameter and 14 mm inside diameter and 150 mm long.6.3 Stirrer, consisting of a 1-mm stainless ste
16、el wire bentinto a circular form at right angles to the shaft so it will movefreely in the annular space between the thermistor and the wallof the test tube.6.4 Stirring Apparatus (Optional)The apparatus illus-trated in Fig. 1 has been demonstrated to be an acceptablereplacement for manual stirring.
17、6.5 Temperature Bath, capable of being controlled at 5 61C below the expected solidification point.6.6 Thermistor, in stainless steel housing with resistancegreater than 2K ohms at 25C. Calibration accuracy 6 0.01C.Drift in resistance equivalent to less than 6 0.01C/year.Thermistor shall be calibrat
18、ed to cover the range it is used.77. Reagents and Materials7.1 Cooling Media:7.1.1 Water is recommended for solidification points be-tween 4 and 30C.7.2 Drying Agents:7.2.1 3A Molecular Sieve, in the form of a powder orcylindrical granules about 3 mm in diameter.8. Hazards8.1 Consult current OSHA re
19、gulations, suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this procedure.8.2 Appropriate personal protection equipment such asgloves, safety glasses, a long rubber apron, and a full faceshield should be worn when handling hot or corrosive chemi-cals, or both.8.3
20、 A fume hood should be used when performing the testmethod on hazardous chemicals (OSHA 1910.1450 definition).9. Sampling and Handling9.1 Sample the material in accordance with PracticesD 3437, D 3438, D 3852, and D 4297.10. Preparation of Apparatus10.1 Fit the sample container with a two-hole stopp
21、er.Through one hole insert the thermistor. Through the other holeinsert the shaft of the stirrer. (See Fig. 1).10.2 Set temperature bath at 5 6 1C. below the expectedsolidification point of the sample.11. Calibration of Thermistor11.1 Thermistor should be calibrated by the factory at aminimum every
22、two years.11.2 The thermistor may be checked by determining the icepoint of water 0.00C.12. Sample Preparation12.1 Solids at Room TemperatureMelt the entire sampleby heating it to about 10C above its solidification point andswirl it for homogeneity.12.2 Drying SamplesIf required by specifications or
23、agreement with customer.12.2.1 p-Xylene should be dried before testing by placingabout 100 g of the material in a 400 mL Erlenmeyer flask andadding about 50 g of 3A molecular sieve.6The sole source of supply of the apparatus known to the committee at this timeis the Hart Scientific Model 1504., 220
24、N. 1300 West, P.O. Box 460, Pleasant Grove,UT 84062. If you are aware of alternative suppliers, please provide this informationto ASTM International Headquarters. Your comments will receive careful consid-eration at a meeting of the responsible technical committee1, which you may attend.7The sole so
25、urce of supply of the apparatus known to the committee at this timeis Thermometrics, type CSP A727X-CSP60BA252M. 808 U.S. Highway #1,Edison, NJ 08817. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consi
26、deration at a meeting of the responsible technical committee1, whichyou may attend.D687503212.3 Benzene is a special case and should be saturated withwater as follows:12.3.1 Place 7 to 8 mL of the specimen in the samplecontainer.12.3.2 Add 1 drop of water to the specimen.12.3.3 Shake the sample tube
27、 vigorously.13. Procedure13.1 Place 7 to 8 mL of the specimen from step 12.2 or 12.3in the sample container.13.2 Insert the stopper with the thermistor and stirrer intothe sample container and adjust the thermistor so that it is about5 mm from the bottom.13.3 Place the sample container in the consta
28、nt temperaturebath set at 5 6 1C below the expected solidification point. Inthe case of cyclohexane, the constant temperature bath shouldbe set about 0.3C below the expected solidification point.13.4 Stir the specimen continuously and observe the tem-perature readings closely. The temperature will f
29、all to aminimum (super cooling), then rise to a maximum. Record themaximum temperature.13.5 If distinct minimum and maximum points are notevident, the determination shall be repeated. If the temperaturedoes not rise to a maximum, increase the constant temperaturebath temperature slightly and repeat
30、the solidification pointdetermination. Repeat increasing the temperature until a mini-mum temperature is observed and the temperature then rises toa maximum.14. Calculations14.1 Benzene results should be reported on an anhydrousbasis by adding 0.09C to the observed maximum temperaturefollowing the m
31、inimum.14.2 All other results should be reported as observed.15. Report15.1 Results shall be reported to the nearest 0.01C.FIG. 1 Solidification Point Apparatus Set UpD687503316. Precision and Bias16.1 Benzene8Based on seven labs analyzing threesamples on two different days.16.1.1 Intermediate Preci
32、sion (formerly calledRepeatability)Results in the same laboratory should not beconsidered suspect unless they differ more than 0.04C. On thebasis of test error alone, the difference between the resultsobtained in the same laboratory on the same material will beexpected to exceed this value only 5 %
33、of the time.16.1.2 ReproducibilityResults submitted by each of twolaboratories should not be considered suspect unless they differby more than 0.05C. On the basis of test error alone, thedifference between two test results obtained in different labo-ratories on the same material will be expected to
34、exceed thisvalue only 5 % of the time.16.2 CyclohexaneBased on a single sample analyzed fivetimes in three different laboratories.16.2.1 RepeatabilityResults in the same laboratory shouldnot be considered suspect unless they differ more than 0.015C.On the basis of test error alone, the difference be
35、tween theresults obtained in the same laboratory on the same materialwill be expected to exceed this value only 5 % of the time.16.2.2 ReproducibilityResults submitted by each of twolaboratories should not be considered suspect unless they differby more than 0.06C. On the basis of test error alone,
36、thedifference between two test results obtained in different labo-ratories on the same material will be expected to exceed thisvalue only 5 % of the time.16.3 p-Xylene9Based on a single sample analyzed fivetimes in six laboratories.16.3.1 RepeatabilityResults in the same laboratory shouldnot be cons
37、idered suspect unless they differ more than 0.026C.On the basis of test error alone, the difference between theresults obtained in the same laboratory on the same materialwill be expected to exceed this value only 5 % of the time.16.3.2 ReproducibilityResults submitted by each of twolaboratories sho
38、uld not be considered suspect unless they differby more than 0.035C. On the basis of test error alone, thedifference between two test results obtained in different labo-ratories on the same material will be expected to exceed thisvalue only 5 % of the time.16.4 BiasSince there is no accepted referen
39、ce materialsuitable for determining the bias for this procedure, bias hasnot been determined.17. Keywords17.1 benzene; cyclohexane; p-Xylene; solidification pointASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this st
40、andard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be rev
41、iewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsi
42、ble technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
43、onshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).8Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D16-1028.9Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D16-1027.D6875034
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