1、Designation: D2710 09 (Reapproved 2013)Designation: 299/92 (98)Standard Test Method forBromine Index of Petroleum Hydrocarbons by ElectrometricTitration1This standard is issued under the fixed designation D2710; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the amountof bromine-reactive ma
3、terial in petroleum hydrocarbons and isthus a measure of trace amounts of unsaturates in thesematerials. It is applicable to materials having bromine indexesbelow 1000.1.2 This test method is applicable only to essentially olefin-free hydrocarbons or mixtures that are substantially free frommaterial
4、 lighter than isobutane and have a distillation end pointunder 288C (550F).NOTE 1This procedure has been cooperatively tested on materialswith bromine indexes in the range from 100 to 1000. These materialsinclude petroleum distillates such as straight-run and hydrocrackednaphtha, reformer feed, kero
5、sine, and aviation turbine fuel.NOTE 2Materials with bromine index greater than 1000 should betested for bromine number using Test Method D1159/IP 130.NOTE 3Bromine index of industrial aromatic hydrocarbons should bedetermined using Test Method D1492 or D5776. The subcommittee iscurrently examining
6、ways to achieve more consistent end point values.1.3 The values stated in SI units are to be regarded asstandard. The values stated in inch-pound units are for infor-mation only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
7、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.2. Referenced Documents2.1 ASTM Standards:2D1159 Test Method for Bromine Numbers of PetroleumDistillates and Commercial Aliphatic Olefins
8、 by Electro-metric TitrationD1492 Test Method for Bromine Index of Aromatic Hydro-carbons by Coulometric TitrationD5776 Test Method for Bromine Index of Aromatic Hydro-carbons by Electrometric Titration3. Terminology3.1 Definitions:3.1.1 bromine index, nthe number of milligrams of bro-mine that will
9、 react with 100 g of sample under the conditionsof the test.4. Summary of Test Method4.1 A known mass of the sample dissolved in a specifiedsolvent is titrated with standard bromide-bromate solution. Theend point is indicated by a dead stop electrometric titrationapparatus when the presence of free
10、bromine causes a suddenchange in the electrical conductivity of the system.5. Significance and Use5.1 This test method provides a measure of trace amounts ofunsaturated hydrocarbons in petroleum distillates boiling up to288C (550F). An estimate of the quantity of these materialsis useful in assessin
11、g the suitability of the lighter fractions foruse as reaction solvents.6. Apparatus6.1 Electrometric End Point Titration ApparatusAny ap-paratus designed to perform titrations to pre-set end points (seeNote 4) may be used in conjunction with a high-resistance1This test method is under the jurisdicti
12、on of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.04.0D on Physical and Chemical Methods.Current edition approved Oct. 1, 2013. Published October 2013. Originallyapproved in 1968. Last previous edition approved in 2009 as D
13、2710 09. DOI:10.1520/D2710-09R13.In the IP, this test method is under the jurisdiction of the StandardizationCommittee.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
14、to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1polarizing current supply capable of maintaining approxi-mately 0.8 V across two platinum electrodes and with asensitivity such
15、that a voltage change of approximately 50 mVat these electrodes is sufficient to indicate the end point. Othertypes of commercially available electric titrimeters, includingcertain pH meters, have also been found to be suitable.NOTE 4Pre-set end point indicated with polarized electrodes providesa de
16、tection technique similar to the dead stop technique specified inprevious versions of this test method.6.2 Titration VesselA jacketed glass vessel of approxi-mately 150-mL capacity of such a form that can be conve-niently maintained at 0 to 5C (32 to 41F). A pair of platinumelectrodes spaced not mor
17、e than 5 mm apart shall be mountedto extend well below the liquid level. Stirring shall be by amechanical or electromagnetic stirrer and shall be rapid, butnot so vigorous as to draw air bubbles down to the electrodes.6.3 Burets, 10 and 50-mL capacity.6.4 Iodine Number Flasks, glass-stoppered, 500-m
18、L capac-ity.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the AmericanChemical Society where such specifications are available.3Other grades may be used, providing
19、 it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water, or waterof equivalent purity.7.3 Preparation and
20、 Standardization :7.3.1 Bromide-Bromate Standard Solution (0.05 N)Dissolve 5.1 g of potassium bromide (KBr) and 1.4 g potas-sium bromate (KBrO3) in water and dilute to 1 L. Standardizeto four significant figures as follows: Place 50 mL of glacialacetic acid (Warning Poison. Combustible. May be fatal
21、 ifswallowed. Causes severe burns. Harmful if inhaled) and 1 mLof concentrated hydrochloric acid (HCl, sp gr 1.19)(WarningPoison. Corrosive. May be fatal if swallowed.Liquid and vapor cause severe burns. Harmful if inhaled.) in a500-mL iodine number flask. Chill the solution in an ice bathfor approx
22、imately 10 min, and with constant swirling of theflask, add from a 50-mL buret 40 to 45 mL of bromide-bromatesolution, estimated to the nearest 0.01 mL, at a rate such thatthe addition takes between 90 and 120 s. Stopper the flaskimmediately, shake the contents, place it again in the ice bath,and ad
23、d 5 mL of potassium iodide (KI) solution in the lip of theflask.After 5 min, remove the flask from the ice bath and allowthe KI solution to flow into the flask by slowly removing thestopper. Shake vigorously, add 100 mL of water in such amanner as to rinse the stopper, lip, and walls of the flask, a
24、ndtitrate promptly with the standard sodium thiosulfate(Na2S2O3) solution. Near the end of the titration, add 1 mL ofstarch indicator solution and titrate slowly to the disappearanceof the blue color. Calculate the normality of the bromide-bromate solution as follows:N15 A2N2/A1(1)where:N1= normalit
25、y of the bromide-bromate solution,A1= millilitres of the bromide-bromate solution,N2= normality of the Na2S2O3solution, andA2= millilitres of the Na2S2O3solution required for titrationof the bromide-bromate solution.7.3.2 Potassium Iodide Solution (150 g/L)Dissolve 150 gof KI in water and dilute to
26、1 L.7.3.3 Sodium Thiosulfate, Standard Solution (0.05N)Dissolve 12.5 g of sodium thiosulfate pentahydrate (Na2S2O35H2O) in water and add 0.01 g of sodium carbonate (Na2CO3)to stabilize the solution. Dilute to 1 L and mix thoroughly byshaking. Standardize by any accepted procedure that deter-mines th
27、e normality with an error not greater than 60.0002.Restandardize at intervals frequent enough to detect changes of0.0005 in normality.7.3.4 Starch Indicator SolutionMix5gofsoluble starchwith approximately 3 to 5 mL of water. If desired, add about0.65 g salicylic acid as preservative. Add the slurry
28、to 500 mLof boiling water and continue boiling for 5 to 10 min. Allow tocool and decant the supernatant liquid into glass bottles andseal well. Starch solutions (some preserved with salicylic acid)are also commercially available and may be substituted.7.3.5 Sulfuric Acid (1+5)Carefully add 1 volume
29、ofconcentrated sulfuric acid (H2SO4, sp gr 1.84) to 5 volumes ofwater and thoroughly mix. (Warning Poison. Corrosive.Strong oxidizer. Contact with organic material may cause fire.May be fatal if swallowed.)7.3.6 Titration SolventPrepare 1 L of titration solvent bymixing the following volumes of mate
30、rials: 714 mL of glacialacetic acid, 134 mL of 1,1,1-trichloroethane ordichloromethane, 134 mL of methanol, and 18 mL of H2SO4(1+5) (see 7.3.5).7.4 Solvents:7.4.1 Acetic Acid, glacial. (WarningPoison. Combus-tible. May be fatal if swallowed. Causes severe burns. Harmfulif inhaled.)7.4.2 Methanol (Wa
31、rningFlammable. Vapor harmful.May be fatal if swallowed. Causes severe burns. Harmful ifinhaled.)7.4.3 1,1,1-Trichloroethane (WarningHarmful if inhaled.High concentrations may cause unconsciousness or death.Contact may cause skin irritation and dermatitis.)7.4.4 Dichloromethane (WarningHarmful if in
32、haled.High concentrations may cause unconsciousness or death.Contact may cause skin irritation and dermatitis.)NOTE 5The replacement of 1,1,1-trichloroethane, an ozone-depletingchemical, is necessary because its manufacture and import has beendiscontinued. Dichloromethane is temporarily being allowe
33、d as an alter-native to 1,1,1-trichloroethane until a permanent replacement can be3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for La
34、boratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D2710 09 (2013)2identified and adopted by ASTM.NOTE 6The user of this test method may choose to use either1,1,1-trichloroethane or dich
35、loromethane to the exclusion of the othersolvent. The selected solvent is to be used for all operations, including thepreparation of the titration solvent and the dilution of samples, ifapplicable.NOTE 7Commercially available reagents can be used in place oflaboratory preparations.8. Procedure8.1 Sw
36、itch on the titrimeter and allow the electrical circuitsto stabilize in accordance with the manufacturers instructions.8.2 Cool the titration vessel to 0 to 5C (32 to 41F) bycirculating a suitable coolant through the jacketed titrationvessel.8.3 Introduce 110 mL of titration solvent into the titrati
37、onvessel and pipet in a quantity of sample as indicated in Table 1.Switch on the stirrer and adjust to a rapid stirring rate, butavoid any tendency for air bubbles to be drawn down into thesolution. Allow the contents to cool to 0 to 5C (32 to 41F)and maintain at this temperature throughout the titr
38、ation.(WarningHydrocarbon samples, particularly those boilingbelow 205C (400F), are flammable.)8.3.1 Frequently the order of magnitude of the bromineindex of a sample is unknown. In this case, a trial test isrecommended using an 8 to 10-g sample in order to obtain theapproximate magnitude of the bro
39、mine index. This exploratorytest should be followed with another determination using theappropriate sample size as indicated in Table 1.8.3.2 The sample mass can be determined by obtaining thedensity of the sample and calculating the mass of a measuredvolume.8.4 Set the end point potential. With eac
40、h instrument, themanufacturers instructions should be followed for end pointsetting and to achieve the sensitivity in the platinum electrodecircuit specified in 6.1.8.5 Depending on the titrator apparatus, add the bromide-bromate solution manually or by microprocessor control insmall increments from
41、 the buret. The end point of the titrationis achieved when the potential reaches the pre-set value (see8.4) and persists for more than 30 s.8.6 BlanksMake duplicate blank titrations on each batchof titration solvent and reagents. Less than 1.0 mL of bromide-bromate solution should be required.9. Cal
42、culation9.1 Calculate the bromine index as follows:Bromine index 5 A 2 B!N 37990#/W (2)where:A = millilitres of bromide-bromate solution required fortitration of the sample,B = millilitres of bromide-bromate solution required fortitration of the blank,N = normality of bromide-bromate solution, andW
43、= grams of sample.10. Precision and Bias10.1 Precision:10.1.1 The precision of this test method as obtained bystatistical examination of interlaboratory test results is asfollows:10.1.1.1 RepeatabilityThe difference between successivetest results obtained by the same operator with the sameapparatus
44、under constant operating conditions on identical testmaterial would, in the long run, in the normal and correctoperation of the test method, exceed 14 in only one case intwenty.10.1.1.2 ReproducibilityThe difference between twosingle and independent results, obtained by different operators,working i
45、n different laboratories on identical test material,would in the long run, in the normal and correct operation ofthe test method, exceed 118 in only one case in twenty.10.2 BiasThe procedure in this test method has no biasbecause the value of bromine index can be defined only interms of a test metho
46、d.NOTE 8The precision for this test method was not obtained inaccordance with: RR:D02-1007.NOTE 9It is not known whether the precision estimates are applicablewhen using dichloromethane as a constituent of the titration solvent.11. Keywords11.1 bromide-bromate solution; bromine index; electromet-ric
47、 titration; hydrocarbons; petroleumTABLE 1 Sample SizeBromine Index Sample Size,g100 to 500 10 to 8Over 500 to 1000 8 to 4D2710 09 (2013)3ANNEX(Mandatory Information)A1. RESULTS OF BROMINE INDEX COOPERATIVE PROGRAMASTM International takes no position respecting the validity of any patent rights asse
48、rted 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 own responsibility.This standard is subject to revision at any time by
49、 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 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, at the
