1、Designation:D 6269 98e1Test Method forSolidification Point ofp-Xylene1This standard is issued under the fixed designation D 6269;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 parentheses indica
2、tes the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.e1NOTERR:D161027 was added editorially in March 2002.1.Scope1.1 This test method covers the determination of the solidi-fication point of p-Xylene with purity greater than 99.5%
3、.NOTE1Other test methods for determining freeze point and solidifi-cation point of aromatic hydrocarbons include Test Methods D 852,D 1015,D 1016,and D 1493.1.2 The following applies to all specified limits in this testmethod:for purposes of determining conformance with thistest method,an observed v
4、alue or a calculated value shall berounded off“to the nearest unit”in the last right hand digit usedin expressing the specification limit,in accordance with therounding-off method of Practice E 29.1.3 This standard does not purport to address all the safetyconcerns,if any,associated with its use.It
5、is the responsibilityof the user of this test method to establish appropriate safetyand health practices and determine the applicability of regu-latory limitations prior to use.For a specific hazard statement,see Section 7.2.Referenced Documents2.1 ASTM Standards:D 852 Test Method for Solidification
6、 Point 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 CyclicProducts2E 29 Practic
7、e for Using Significant Digits in Test Data toDetermine Conformance with Specifications42.2Other Documents:OSHA Regulations,29 CRFR,paragraphs 1910.1000 and1910.120053.Terminology3.1 Definitions:3.1.1 solidification pointan empirical constant defined asthe temperature at which the liquid phase of a
8、substance is inapproximate equilibrium with a relatively small portion of thesolid phase.3.1.1.1 DiscussionSolidification point as distinguishedfrom freezing point is described in Test Method D 1015.Aninterpretation of mole percent in terms of freezing point isgiven in Test Method D 1016.3.1.2 anhyd
9、rousp-xylene that has been treated with 3Amolecular sieve to remove water.4.Summary of Test Method4.1 P-Xylene is dried with a 3-A molecular sieve.Thesolidification point is then measured by noting the maximumtemperature reached after the appearance of a solid phase.5.Significance and Use5.1 This te
10、st method may be used for process control duringthe manufacture of p-xylene,for setting specifications,and todetermine if contamination was introduced into the p-xyleneduring shipment.6.Apparatus6.1 Temperature Bath,controlled at 10 6 1C.6.2 Ohm Meter6,7,capable of measuring resistance to thenearest
11、 0.1 V in range 1000 to 10 000 V with directtemperature readout.6.3 Sample Container,thick walled test tube with 18-mmoutside diameter and 14-mm inside diameter,and 150-mmlong.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and are the
12、direct responsibility ofSubcommittee D16.04 on Instrumental Analysis.Current edition approved May 10,1998.Published July 1998.2Annual Book of ASTM Standards,Vol 06.04.3Annual Book of ASTM Standards,Vol 05.01.4Annual Book of ASTM Standards,Vol 14.02.5Available fro the Superintendent of Documents,U.S.
13、Government PrintingOffice,Washington,DC 20402.6The sole source of supply of an ohm meter meeting these specifications is theHart Scientific Model 1504.,220 N.1300 West,P.O.Box 460,Pleasant Grove,Utah84062.7If you are aware of alternative suppliers,please provide this information toASTM International
14、 Headquarters.Your comments will receive careful consider-ation at a meeting of the responsible technical committee,D16,which you mayattend.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.6.4 Stirrer,consisting of a 1-mm copper or stainle
15、ss steelwire(copper or stainless steel)bent into a circular form at rightangles to the shaft so it will move freely in the annular spacebetween the thermistor and the wall of the test tube.6.5 Stirring Apparatus,(Optional)The apparatus illustratedin Fig.1 has been demonstrated to be an acceptable re
16、place-ment for manually stirring the p-xylene solution.6.6 Thermistor7,8in stainless steel housing with resis-tance greater than 2 kV at 25C.Calibration accuracy60.005C.from 0 to 25C.Drift in resistance equivalent toless than 60.005C/year.7.Reagents and Materials7.1 Insulation,dry absorbent cotton or glass wool.7.2 3-A Molecular Sieve,in the form of a powder orcylindrical granules about 3 mm in diameter.8.Hazards8.1 Consult current OSHA regulations,suppliers MaterialSafety Data Sheets,and local
