1、Designation: D 852 08Standard Test Method forSolidification Point of Benzene1This standard is issued under the fixed designation D 852; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the solidi-fication point of benzene.1.2 In determining the conformance of the test results usingthis metho
3、d to applicable specifications, results shall berounded off in accordance with the rounding-off method ofPractice E29.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesa
4、fety concerns, if any, 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. For specific hazardstatements, see Section 7.2. Referenced Documents2.1
5、ASTM Standards:2D 1015 Test Method for Freezing Points of High-PurityHydrocarbonsD 1016 Test Method for Purity of Hydrocarbons fromFreezing PointsD 1193 Specification for Reagent WaterD 3437 Practice for Sampling and Handling Liquid CyclicProductsD 6809 Guide for Quality Control and Quality Assuranc
6、eProcedures for Aromatic Hydrocarbons and Related Ma-terialsE1 Specification for ASTM Liquid-in-Glass ThermometersE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Te
7、st Method2.2 Other Document:OSHA Regulations, 29CFR paragraphs 1910.1000 and1910.120033. 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
8、 solid phase.3.1.1.1 DiscussionSolidification point is distinguishedfrom freezing point which is described in Test Method D 1015.An interpretation of mol percent purity in terms of freezingpoint is given in Test Method D 1016.4. Summary of Test Method4.1 Solidification point is measured by noting th
9、e maximumtemperature reached during a controlled cooling cycle after theappearance of a solid phase.5. Significance and Use5.1 This test method may be used as a criteria for determin-ing the purity of benzene. The closer the solidification pointreaches that of pure benzene, the purer the sample.6. A
10、pparatus6.1 Benzene Container (Air Jacketed):6.1.1 Inner Container, a test tube 15 mm in outside diameterand 125 mm in length.6.1.2 Air Jacket, a standard test tube 25 mm in outsidediameter and 150 mm in length.6.1.3 InsulationDry absorbent cotton or glass wool.6.2 Benzene Container (thick walled),
11、a glass test tube 18mm in outside diameter, 14 mm in inside diameter and 150 mmin length. The thick walled tube is only compatible with thethermistor.6.3 Ice Bath, a 1-L beaker, or similar suitable container,having an effective depth of at least 127 mm and filled withchipped or shaved ice.6.4 Stirre
12、r, consisting of a 1-mm wire (copper or stainlesssteel) or a 2-mm glass rod with one end bent into a circular1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.01 on Benzene, Toluene, Xyl
13、enes, Cyclohexane and TheirDerivatives.Current edition approved July 15, 2008. Published August 2008. Originallyapproved in 1945. Last previous edition approved in 2002 as D 852 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.or
14、g. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.1*A Summary of Ch
15、anges section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.form at right angles to the shaft so that it will move freely inthe annular space between the thermometer stem and the wallof the smalle
16、r test tube.6.5 Temperature Measurement Device, either device de-scribed below has been found satisfactory.6.5.1 Thermometer, an ASTM Benzene Freezing PointThermometer having a range from 4.0 to 6.0C and conform-ing to the requirements for Thermometer 112C as prescribed inSpecification E1.6.5.2 Ther
17、mistor, in stainless steel housing with resistancegreater than 2K ohms at 25C. Calibration accuracy 0.01C.Drift in resistance equivalent to less than 6 0.01C/year.Thermistor shall be calibrated to cover the range it is used.46.6 Stirring Apparatus (Optional), the apparatus illustratedin Fig. 1 has b
18、een demonstrated to be an acceptable replace-ment for manually stirring the benzene solution.6.7 Ohmeter, capable of measuring resistance to the nearest0.1 ohm in the range 1000 to 10 000 ohms with directtemperature readout.44The sole source of supply of the apparatus known to the committee at this
19、timeis GE Thermometrics, type CSP A 727X-CSP60BA252M, 967 Windfall Rd., St.Marys PA 15857. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee
20、,1whichyou may attend.FIG. 1 Benzene Solidification Point Apparatus Set UpD8520827. Hazards7.1 Consult current OSHA regulations, suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this test method.7.2 WarningMercury has been designated by EPA andmany state agencies
21、as a hazardous material that can causecentral nervous system, kidney, and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury-containing products. See the applicable product Ma-terial Safety Data Sheet (MS
22、DS) for details and EPAs website(http:/www.epa.gov/mercury/faq.htm) for additional informa-tion. Users should be aware that selling mercury or mercury-containing products, or both, in your state may be prohibited bystate law.8. Sampling8.1 Sample the material in accordance with PracticeD 3437.9. Pre
23、paration of Apparatus9.1 Fit the benzene container with a two-hole stopper.Through one hole insert the temperature measurement device.The thermometer should be inserted up to the 4.0C mark. Thethermistor should be inserted, so as to contact the benzenesolution. Through the other hole insert the shaf
24、t of the stirrer.9.2 If using the benzene container (air jacketed), place a3.2-mm layer of dry absorbent cotton or glass wool in thebottom of the larger test tube and insert the inner container upto the lip into a stopper or annular ring that just fits into themouth of the air jacket.10. Calibration
25、 of Temperature Measuring Device10.1 Calibration of ASTM thermometer 112C is accom-plished with the small scale etched on the lower portion of thethermometer. Prepare an ice bath by filling a small Dewar flaskwith crushed ice made from Type I or Type II water (asspecified in Specification D 1193) an
26、d add just enough chilledType I or Type II water to make a slurry. Immerse thethermometer in the ice bath, allow 5 min for the system toreach equilibrium and read the thermometer. Solidificationpoint values are subsequently adjusted by adding (or subtract-ing) the number of degrees the thermometer i
27、s below (orabove) 0.00C.10.2 Calibration of the thermistor is performed by thethermistor manufacturer. Resistance is converted to tempera-ture using an equation supplied by the manufacturer.11. Procedure11.1 Saturate the sample of benzene with water as follows:Place 7 to 8 mL of the sample in the be
28、nzene container, add 1drop of water, and shake the tube and contents vigorously.11.2 Place the stopper and stirring apparatus (if any) into thebenzene container.11.3 When using the benzene container (air jacket), theoperator may cool the smaller test tube and contents rapidly toabout 6C in the ice b
29、ath, while stirring. Wipe dry the outsideof the smaller test tube and insert it into the larger test tube.Place the assembled tubes in the ice bath.11.4 Stir the benzene continuously and observe the tempera-ture closely. The temperature will fall to a minimum, then riseto a maximum, remain constant
30、at this maximum for approxi-mately 15 s, and then fall again (Note 1). The minimumtemperature is due to super-cooling before solidification startsand shall not be more than 0.7C below the maximum whenusing a thermometer. Record the maximum constant tempera-ture observed to the nearest 0.01C and desi
31、gnate it as “wet”(Note 1).NOTE 1If distinct minimum and maximum points are not evident, orif the temperature does not remain constant at the maximum for at least15 s, the determination shall be repeated. The thermistor reading shouldremain constant to at least two places to the right of the decimal.
32、12. Report12.1 Results shall be reported on the anhydrous basis. Sincethe determination is actually made on water-saturated benzene,the solidification point shall be corrected to the anhydrous basisby adding 0.09C to the observed maximum temperaturefollowing the minimum. Corrections for accuracy of
33、thethermometer shall be made.13. Precision and Bias513.1 Thermometer PrecisionThe following criteriashould be used to judge the acceptability of results obtained bythis test method when using a thermometer. The criteria weredetermined by measuring the solidification point of a sampletwelve times at
34、one laboratory using a thermometer. The resultsof the intralaboratory study were calculated and analyzed usingPractice E 691. Duplicate results in the same laboratory shouldnot be considered suspect unless they differ by more than0.04C.13.2 Thermistor PrecisionThe following criteria shouldbe used to
35、 judge the acceptability (95 % probability level) ofresults obtained by this test method when using a thermistor.The criteria were derived from an interlaboratory study be-tween six laboratories. Three different samples were analyzedin triplicate on two different days using a thermistor and a thickw
36、alled glass test tube. The results of the intralaboratory studywere calculated and analyzed using Practice E 691.13.2.1 Intermediate PrecisionResults in the same labora-tory should not be considered suspect unless they differ morethan 0.04C. On the basis of test error alone, the differencebetween tw
37、o results obtained in the same laboratory on thesame material will be expected to exceed this value only 5 %of the time.13.2.2 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, thediffe
38、rence between two test results obtained in different labo-ratories on the same material will be expected to exceed thisvalue only 5 % of the time.13.3 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure, bias has notbeen determined.5Supporting data ha
39、ve been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D161028.D85208314. Quality Guidelines14.1 Refer to Guide D 6809 for suggested QA/QC activitiesthat can be used as a part of this method. It is recommendedthat the operator of this method select and p
40、erform relevantQA/QC activities like the ones in Guide D 6809 to help ensurethe quality of data generated by this method.15. Keywords15.1 benzene; solidification pointSUMMARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue (D 852 - 02)tha
41、t may impact the use of this standard. (Approved July 15, 2008.)(1) Corrected typos and modified 6.5.2 to correct for units forresistance and Section 7 to add mercury caveat.(2) Updated to conform to current editorial guidelines andadded footnote to include sole source for thermistor.ASTM Internatio
42、nal takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. 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
43、 own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed 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
44、 addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible 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
45、, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, 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).D852084
