1、Designation: D1747 09 (Reapproved 2014)Standard Test Method forRefractive Index of Viscous Materials1This standard is issued under the fixed designation D1747; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test method covers the measurement of
3、refractiveindexes, accurate to two units in the fourth decimal place, oftransparent and light-colored viscous hydrocarbon liquids andmelted solids that have refractive indexes in the range between1.33 and 1.60, and at temperatures from 80 to 100C. Tem-peratures lower than 80C can be used provided th
4、at themelting point of the sample is at least 10C below the testtemperature.1.2 This test method is not applicable, within the accuracystated, to liquids having colors darker thanASTM Color No. 4,ASTM color as determined by Test Method D1500, to liquidswhich smoke or vaporize readily at the test tem
5、perature, or tosolids melting within 10C of the test temperature.NOTE 1The instrument can be successfully used for refractive indicesabove 1.60; but since certified liquid standards for ranges above 1.60 arenot yet available, the accuracy of measurement under these conditions hasnot been evaluated.1
6、.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 WarningMercury has been designated by EPA andmany state agencies as a hazardous material that can causecentral nervous system, kidney, and liver damage. Mercury, orits vapor
7、, 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 (MSDS) for details and EPAs website(http:/www.epa.gov/mercury/faq.htm) for additional informa-tion. Users shoul
8、d be aware that selling mercury or mercury-containing products, or both, in your state may be prohibited bystate law.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priat
9、e safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D362 Specification for Industrial GradeToluene (Withdrawn1989)3D841 Specification for Nitration Grade TolueneD1500 Test Method for ASTM Color of Petroleum
10、Products(ASTM Color Scale)D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceE1 Specification for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of Ther-mometers3. Terminology3
11、.1 Definitions:3.1.1 refractive indexthe ratio of the velocity of light (ofspecified wavelength) in air, to its velocity in the substanceunder examination. The relative index of refraction is definedas the sine of the angle of incidence divided by the sine of theangle of refraction, as light passes
12、from air into the substance.If absolute refractive index (that is, referred to vacuum) isdesired, this value should be multiplied by the factor 1.00027,the absolute refractive index of air. The numerical value ofrefractive index of liquids varies inversely with both wave-length and temperature.4. Su
13、mmary of Test Method4.1 The refractive index normally is measured by the criticalangle method using monochromatic light from a sodium lamp.The instrument is previously adjusted by means of calibrationobtained with certified liquid standards.1This test method is under the jurisdiction of ASTM Committ
14、ee D02 onPetroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.04.0D on Physical and Chemical Methods.Current edition approved June 1, 2014. Published July 2014. Originally approvedin 1960. Last previous edition approved in 2009 as D174709. DOI: 10.1520/
15、D1747-09R14.2For 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 last approved version of this historical sta
16、ndard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 Refractive index is a fundamental physical property thatcan be used in conjunction with other properties to characterizepure
17、 hydrocarbons and their mixtures.5.2 The use of refractive index in correlative methods forthe determination of the gross composition of viscous oils andwaxes often requires its measurement at elevated temperatures.6. Apparatus6.1 Refractometer, precision Abb-type,4having a range inrefractive index
18、from 1.30 to 1.63. Other instruments readingto at least four decimal places may be used.NOTE 2When other instruments are used, follow the manufacturersinstructions for operation, maintenance, calibration, and analysis. Foraccepting the instrumentation for use, analysis of an NIST traceablecertified
19、material to ensure accuracy should be performed.6.2 Thermostat and Circulating Pump, capable of maintain-ing the indicated prism temperature constant within 0.02C.The circulating fluid consists of ethylene glycol or a mixture of30 to 40 volume % of glycerin in water flowing through theprisms at a fi
20、xed rate of at least 2.5 L/min. For work at 100C,properly controlled wet steam is also suitable.NOTE 3The constancy of the prism temperature can be seriouslyaffected by variations in ambient conditions, such as air drafts or changesin room temperature. Reasonable precautions should be taken to minim
21、izethese factors. Insulation placed on the thermostat, circulating fluid lines,and refractometer also may prove to be helpful.6.3 Thermometers, or Equivalent Temperature MeasuringDevices, conforming to Thermometer 21C for determinationsat 80C or Thermometer 22C for determinations at 100C asgiven in
22、Specification E1 are recommended. See Test MethodE77 for guidance on inspection and verification of mercury inglass thermometers. Equivalent temperature measuring devicesshould have the same accuracy and resolution as Thermom-eters 21C and 22C.6.3.1 In case of dispute, the test method shall be carri
23、ed outusing the specified mercury in glass thermometer.6.3.2 The temperature measuring device, suitablycalibrated, shall be positioned to measure the temperature ofthe prism (see Note 4) within an appropriate holder. The holdershall provide for adequate immersion of the temperaturemeasuring device a
24、nd for free flow of the circulating fluid. Thetemperature measuring device holder assembly shall be insu-lated with a suitable material, such as cork.NOTE 4In the precision Abb type refractometer, the thermostatingliquid should pass the thermometer on leaving, not on entering, the prismassembly.6.4
25、Thermocouple,5copper-constantan foil type, 0.013-mmthickness, and precision potentiometer. The thermocouple iscalibrated by immersing to a depth of 25 mm in a circulatingliquid thermostat and comparing with a thermometer of knownaccuracy.6.5 Light Source, Sodium Arc LampThe light source shallbe a so
26、dium arc lamp, which shall be used only after theremoval ofAmici compensating prisms, if there are any presentin the instrument.NOTE 5If the field division as observed in 12.2 shifts when theAmiciprism is rotated, the prism should be removed to avoid incorrect readings.7. Solvents7.1 Cleaning Solven
27、t, any suitable solvent capable of clean-ing the apparatus as described in Section 10. 1,1,1, Trichlo-roethane has been found suitable to use. (WarningHarmfulif inhaled. High concentration can cause unconsciousness ordeath. Contact can cause skin irritation and dermatitis.)7.2 Toluene, conforming to
28、 Specification D362 or Specifi-cation D841.(WarningFlammable. Vapor harmful.)8. Reference Standards8.1 Primary Liquid StandardsOrganic liquids listed inTable 1, with the values of their refractive indexes for thesodium D line certified at 20, 25, 30, 80, and 100C.6(Warning Primary standards are comb
29、ustible.)8.2 Working StandardsFor working standardhydrocarbons, reasonably well purified samples ofn-hexadecane, trans -decahydronaphthalene, and1-methylnaphthalene may be used. Their exact values aredetermined by comparison with standard samples of the samehydrocarbons having certified values of re
30、fractive index.(WarningWorking standards are combustible.)9. Sample9.1 Asample of at least 0.5 mLis required.The sample shallbe free of suspended solids, water, or other materials that tendto scatter light. Water can be removed from hydrocarbons bytreatment with calcium chloride followed by filterin
31、g orcentrifuging to remove the desiccant. The possibility of chang-ing the composition of a sample by action of the drying agent,by selective adsorption on the filter, or by fractionalevaporation, shall be considered.10. Preparation of Apparatus10.1 The refractometer shall be kept scrupulously clean
32、 atall times. Dust and oil, if allowed to accumulate on any part ofthe instrument, will find its way into the moving parts, causing4The Abb-type precision refractometer is no longer available but may beobtainable from instrument exchanges or used equipment suppliers. Other precisionrefractometers ma
33、y be suitable, but they have not as yet been tested cooperatively.5The sole source of supply of the apparatus known to the committee at this timeis RdF Corp., 23 Elm Avenue, Hudson, NH 03051. If you are aware of alternativesuppliers, please provide this information to ASTM International Headquarters
34、.Your comments will receive careful consideration at a meeting of the responsibletechnical committee1, which you may attend.6Available from API Standard Reference Office, Carnegie-Mellon University,Pittsburgh, PA 15213.TABLE 1 Primary Liquid StandardsCertified StandardApproximate Refractive Index,nD
35、n-Hexadecane 1.41trans-Decahydronaphthalene 1.441-Methylnaphthalene 1.59D1747 09 (2014)2wear and eventual misalignment. If permitted to collect on theprism, dust will dull the polish, resulting in hazy lines.10.2 Thoroughly clean the prism faces with fresh clean lenstissue or surgical grade absorben
36、t cotton saturated with asuitable solvent. Pass the swab very lightly over the surfaceuntil it shows no tendency to streak. Repeat the procedure witha fresh swab and solvent until both the glass and adjacentpolished metal surfaces are clean. Do not dry the prism facesby rubbing with dry cotton.10.3
37、Adjust the thermostat so that the temperature as indi-cated by the thermocouple inserted between the prism facesand wet with oil is within 0.2C of the desired test temperature.This temperature is to be held constant to within 0.02C duringthe test. Observe and record the thermometer reading corre-spo
38、nding to the test temperature. Turn on the sodium arc lampand allow it to warm up for 30 min.11. Standardization with Reference Liquids11.1 Introduce a sample of the API Standard trans-decahydronaphthalene to the prism which is adjusted to thechosen test temperature of 80 or 100C, turn the telescope
39、adjustment screw until a refractive index scale reading corre-sponding to the certified refractive index for trans-decahydronaphthalene is observed, and adjust the instrumentaccording to the instructions given by the manufacturer untilthe sharp boundary between the light and dark portions of thefiel
40、d passes through the intersection of the cross hairs of thetelescope.11.2 Check the accuracy of this setting by loading a freshsample of trans-decahydronaphthalene and measure its refrac-tive index at the test temperature following the proceduredescribed in Section 12. If the value for the refractiv
41、e indexdiffers from the certified value by 0.0001 or more units, thenrepeat the procedure given in 11.1 until a satisfactory check isobtained.11.3 Measure the refractive index of API Standardn-hexadecane and 1-methylnaphthalene at the test temperaturefollowing the procedure described in Section 12.1
42、1.4 Construct a calibration curve for use at the chosen testtemperature. Plot the difference between the observed refrac-tive index for n-hexadecane and its certified value along theordinate against the refractive index level along the abscissa.Also plot the difference between the observed and certi
43、fiedrefractive indices for 1-methylnaphthalene in the same manner.Draw a straight line from the point representing the deviationfound for n-hexadecane to zero at the certified refractive indexof trans-decahydronaphthalene. Likewise, draw a straight linefrom this same zero point to the deviation foun
44、d for1-methylnaphthalene.11.5 If it is desired to measure the refractive index ofsamples at a temperature other than 80 or 100C, obtaincalibration data by repeating 11.1 11.4 at this desiredtemperature. Determine the refractive indices for the APIStandard compounds, n-hexadecane, trans-decahydronaph
45、thalene, and 1-methylnaphthalene at the desiredtemperature by plotting the certified refractive indices at 20,25, 30, 80, and 100C against temperature and drawing asmooth curve between the points.11.6 PrecautionsIn using pure liquids for calibration orchecking of calibration of an Abb-type refractom
46、eter, thefollowing precautions should be observed:11.6.1 Before inserting the hydrocarbon calibrating liquids,the prisms should be flushed with solvents and cleaned asdescribed in 8.2. It is advisable to preheat the solvent beforeuse to minimize thermal shock to the prism. This should befollowed by
47、several such flushings with the test liquid andwiping with lens paper. After such cleaning, a reading with thetest liquid should be taken as described in Section 11. Thisshould be followed by another flushing with the test liquidbefore taking another reading of the test liquid in the prescribedmanne
48、r. The prisms cannot be considered free from contami-nating substances until two such determinations on the testliquid agree within the limits given in 11.6.2.11.6.2 In setting the edge of the field on the cross hairs,readings should be taken in pairs, approaching the alidadesetting from one directi
49、on only as recommended by themanufacturer. Several such sets will probably be necessarybefore satisfactory agreement is obtained. Satisfactory agree-ment is 0.00005 to 0.0001.11.6.3 For results of highest accuracy, the calibration withhydrocarbons of known properties should be made immedi-ately before the determination on the sample.11.6.4 Fluctuations in ambient temperatures should be mini-mized as much as possible during the test.12. Procedure12.1 Thoroughly clean the prism faces as described in 10.2.Adjust the thermostat so that the temperatur
