ASTM_D_936_-_89_scan.pdf

ASTM DY36 89 M 0759510 OOLl0309 T 9 24-I 6 AMERICAN SOCIETY FOR TESTINO AND MATERIALS 1016 ASCO SI.,PhMehm,PI.19103 Reprinted h O m lh.Anmiil Boa oi ASTM Standards,COplrQhi ASTM II rol ikd in lha c u m cmbined krdai.will w i r hi lha wnt rdiiim.An American National Standard 41)Designation:D 936-89 Standard Test Method for Aromatic Hydrocarbons in Olefin-Free Gasolines by Silica Gel Adsorption This standard is issued under the fixed designation D 936;the number imrnediafely foliowing the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(c)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Deparimeni of Dejiense and repiaces Method 3702 of Federal Test Method Standard No.791b.Consult the DoD Index of Specijications and Standardsfor the spec$c year of issue which has been adopted by the Department o f Defense.1.Scope 1.1 This test method covers the determination of total aromatic content of gasolines and other debutanized hydro-carbon mixtures that distill below 204C(400F)and contain less than 1%of olefinic hydrocarbons.1.2 The values stated in SI units are to be regarded as the standard.The values in parentheses are for information only.1.3 This standard may involve hazardous materials,oper-ations,and equipment.This standard does not purport to address all o f the safety problems associated with its use.It is the responsibility o f the user o f this standard to establish appropriate safity and health practices and determine the applicability o f regulatory limitations prior to use.Specific hazard statements are given in Section 7 and Annex Al.2.Referenced Documents 2.1 ASTM Standards:D941 Test Method for Density and Relative Density(Specific Gravity)of Liquids by Lipkin Bicapillary Pycnomete?D 1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorp-tion2 E 11 Specification of Wire-Cloth Sieves for Testing Pur-poses3 3.Summary of Test Method4 3.1 The sample is passed downward through a column packed with fine,activated silica gel and,when all of the sample has been adsorbed on the gel,alcohol is added as an eluent.The alcohol causes desorption of the hydrocarbons,-forcing them down the column.In this process of adsorption and desorption,the hydrocarbons are separated according to their adsorption affinities so that the components issue from the bottom of the silica gel column in the following order:*This test method is under the jurisdiction of ASTM Committee D 2 on Petroleum Products and Lubricants and is the direct responsibility of Subcom-mittee D2.04 on Hydrocarbon Analysis.Current edition approved Oct.27,1989.Published December 1989.Originally published as D 936-47.Last previous edition D 936-83.Annual Book o f ASTM Standards,Vol 05.01.Annual Book o f ASTM Standards,Vol 14.02.4For a more complete discussion of this test method,see Mair,B.J.,“Separation and Determination of Aromatic and Monoolefin Hydrocarbons i n Mixtures with Paraflins and Naphthenes by Adsorption,”Journal o f Research,National Institute of Standards and Technology.JRMSB,Vol 34,No.5,1945,p.435.saturates,saturates plus aromatics,aromatics,aromatics plus alcohol,and alcohol.The percolate is collected in small frac-tions and the aromatic content of the sample is calculated from measured volumes and refractive indices of the frac-tions.Samples containing less than 4%aromatics are fortified with a known amount of toluene and those containing more than 80%aromatics are diluted with a saturated hydrocarbon or hydrocarbon mixture boiling in the gasoline range;correc-tion is made in the calculation for the toluene or diluent added.4.Significance and Use 4.1 A precise knowledge of the liquid volume percent of the aromatic hydrocarbons of gasolines and petroleum fractions from which gasolines are blended is of value in assessing the performance properties of the gasolines.Such knowledge is also of value in measuring the conversion of paraffins and cycloparaffins to aromatics by catalytic re-forming.This test method provides a procedure for making such a precise determination.5.Interference 5.1 Paraffins and cycloparaffins do not interfere,regard-less of their concentration.Olefinic hydrocarbons,when present in concentrations greater than one percent,interfere in the normal use of this test method.Compounds con-taining sulfur or nitrogen interfere by being included with the aromatic hydrocarbons.6.Apparatus 6J Adsorption Column,as shown in Fig.1,consisting of an eluent reservoir,a sample reservoir,and wide and narrow sections of a water-jacketed tubing.The column should be surrounded with a transparent protective shield when oper-ating at pressures in excess of 69 kpa(10 psi).6.2 Receiver,graduated,of 1 1-mL capacity,as shown in Fig.2.NOTE 1-Whiie not strictly required,a cathetometer,capable of