ASTM_D_2710_-_09_2013.pdf

Designation:D271009(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 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 material 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 lighter than isobutane and have a distillation end pointunder 288C(550F).NOTE1This 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,kerosine,and aviation turbine fuel.NOTE2Materials with bromine index greater than 1000 should betested for bromine number using Test Method D1159/IP 130.NOTE3Bromine index of industrial aromatic hydrocarbons should bedetermined using Test Method D1492 or D5776.The subcommittee iscurrently examining 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 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.2.Referenced Documents2.1 ASTM Standards:2D1159 Test Method for Bromine Numbers of PetroleumDistillates and Commercial Aliphatic Olefins 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 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 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 assessing 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 jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricantsand is the direct responsibility ofSubcommittee D02.06 on Analysis of Liquid Fuels and Lubricants.Current edition approved Oct.1,2013.Published October 2013.Originallyapproved in 1968.Last previous edition approved in 2009 as D2710 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 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 States1 polarizing current supply capable of maintaining approxi-mately 0.8 V across two platinum electrodes and with asensitivity such 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.NOTE4Pre-set end point indicated with polarized electrodes providesa detection 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 more 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 Io