1、Designation: D1747 09Standard 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 revision. A number in pa
2、rentheses 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 Department of Defense.1. Scope*1.1 This test method covers the measurement of refractiveindexes, acc
3、urate 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 that themelting point of
4、 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 temperature, or tosolids
5、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.1.3 The values stated i
6、n 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, may be hazardous to
7、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 should be aware that sellin
8、g 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-priate safety and health pr
9、actices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D362 Specification for Industrial Grade Toluene3D841 Specification for Nitration Grade TolueneD1500 Test Method forASTM Color of Petroleum Products(ASTM Color Scale)D6299 Practi
10、ce 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. Terminology3.1 Definitions:3.1.1 refractive indext
11、he 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 from air into the substance.If absolut
12、e 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. Summary of Test Method4.1 The refractive
13、 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 Committee D02 onPetroleum Products and Lubric
14、ants and is the direct responsibility of SubcommitteeD02.04.0D on Physical and Chemical Methods.Current edition approved Oct. 1, 2009. Published October 2009. Originallyapproved in 1960. Last previous edition approved in 2004 as D174799(2004)1.DOI: 10.1520/D1747-09.2For referenced ASTM standards, vi
15、sit 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.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.
16、1*A Summary of Changes 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.5. Significance and Use5.1 Refractive index is a fundamental physical property thatcan be used in conjunction with othe
17、r properties to characterizepure 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,4ha
18、ving a range inrefractive index 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, analysi
19、s of an NIST traceablecertified 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 f
20、lowing through theprisms at a fixed 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 prec
21、autions should be taken to minimizethese 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 de
22、terminations at 100C asgiven in 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
23、, the test method shall be carried outusing the specified mercury in glass thermometer.6.3.2 The temperature measuring device, suitably cali-brated, shall be positioned to measure the temperature of theprism (see Note 4) within an appropriate holder. The holdershall provide for adequate immersion of
24、 the temperaturemeasuring device and 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 o
25、n entering, the prismassembly.6.4 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
26、 LampThe light source shallbe a sodium 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 the Amiciprism is rotated, the prism should be removed to avoid incorrect read
27、ings.7. Solvents7.1 Cleaning Solvent, any suitable solvent capable of clean-ing the apparatus as described in Section 10. 1,1,1, Trichloro-ethane has been found suitable to use. (WarningHarmful ifinhaled. High concentration can cause unconsciousness ordeath. Contact can cause skin irritation and der
28、matitis.)7.2 Toluene, conforming to 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
29、(WarningPrimary standards are combustible.)8.2 Working StandardsFor working standard hydrocar-bons, reasonably well purified samples of n-hexadecane, trans-decahydronaphthalene, and 1-methylnaphthalene may be used.Their exact values are determined by comparison with standardsamples of the same hydro
30、carbons having certified values ofrefractive index. (WarningWorking standards are combus-tible.)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 wit
31、h calcium chloride followed by filtering 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 fractional evapora-tion, shall be considered.10. Preparation of Apparatus10.1 The refra
32、ctometer shall be kept scrupulously clean 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 su
33、ppliers. Other precisionrefractometers may 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 infor
34、mation to ASTM International Headquarters.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 StandardsCertifie
35、d StandardApproximate Refractive Index,nDn-Hexadecane 1.41trans-Decahydronaphthalene 1.441-Methylnaphthalene 1.59D1747 092wear 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 len
36、stissue or surgical grade absorbent 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 fac
37、esby rubbing with dry cotton.10.3 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
38、 the thermometer reading corre-sponding 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
39、 of 80 or 100C, turn the telescopeadjustment 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
40、light and dark portions of thefield 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
41、12. If the value for the refractive 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 p
42、rocedure described in Section 12.11.4 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 differe
43、nce between the observed and certifiedrefractive 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 sam
44、e zero point to the deviation found 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 desired tempera-ture. Determine the refractive indices for the API Standardcompound
45、s, n-hexadecane, trans-decahydronaphthalene, and1-methylnaphthalene at the desired temperature by plotting thecertified refractive indices at 20, 25, 30, 80, and 100C againsttemperature and drawing a smooth curve between the points.11.6 PrecautionsIn using pure liquids for calibration orchecking of
46、calibration of an Abb-type refractometer, 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 t
47、he prism. This should befollowed by 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 th
48、e test liquid in the prescribedmanner. 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
49、 the alidadesetting from one direction 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 th
