ASTM_D_7796_-_12.pdf

Designation:D779612An American National StandardStandard Test Method forAnalysis of Ethyl tert-Butyl Ether(ETBE)by GasChromatography1This standard is issued under the fixed designation D7796;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 purityof ethyl tert-butyl ether(ETBE)by gas chromatography.It alsoprovides a procedure to measure impurities in ETBE such asC4to C12olefins,methyl,isopropyl and tert-butyl alcohols,methyl sec-butyl and methyl tert-amyl ethers,acetone,andmethyl ethyl ketone.1.2 This test method is not applicable to the determinationof ETBE in gasoline.1.3 Water cannot be determined by this test method andshall be measured by a procedure such as Test Method D6304and the result used to normalize the chromatographic values.1.4 Most of the impurities in ETBE are resolved by the testmethod,however,some co-elution is encountered.1.5 This test method is inappropriate for impurities that boilat temperatures higher than 180C or for impurities that causepoor or no response in a flame ionization detector,such aswater.1.6 The values stated in SI units of measurement arepreferred and used throughout the standard.Alternate units,incommon usage,are also provided to improve clarity and aid theuser of this test methods.1.7 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:2D3700 Practice for Obtaining LPG Samples Using a Float-ing Piston CylinderD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD4626 Practice for Calculation of Gas ChromatographicResponse FactorsD6304 Test Method for Determination of Water in Petro-leum Products,Lubricating Oils,and Additives by Cou-lometric Karl Fischer TitrationD7618 Specification for Ethyl Tertiary-Butyl Ether(ETBE)for Blending with Aviation Spark-Ignition Engine FuelE355 Practice for Gas Chromatography Terms and Relation-shipsE594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid Chromatography3.Terminology3.1 DefinitionsThis test method makes reference to manycommon gas chromatographic procedures,terms,and relation-ships.Detailed definitions of these can be found in PracticesE355 and E594.3.2 Definitions of Terms Specific to This Standard:3.2.1 C4to C12olefins,ncommon olefin impurities inETBE including unreacted feedstock and dimers or trimers offeed such as trimethylpentene or pentamethylheptene.4.Summary of Test Method4.1 A representative aliquot of the ETBE product sample isintroduced into a gas chromatograph equipped with a methylsilicon bonded phase fused silica open tubular column.Heliumcarrier gas transports the vaporized aliquot through the columnwhere the components are separated by the chromatographicprocess.Components are sensed by a flame ionization detectoras they elute from the column.4.2 The detector signal is processed by an electronic dataacquisition system or integrating computer.Each eluting com-ponent is identified by comparing its retention time to thoseestablished by analyzing standards under identical conditions.4.3 The concentration of each component in mass percent isdetermined by normalization of the peak areas after each peakarea has been corrected by a detector response multiplicationfactor and the water content of the sample.The detector1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.J0.02 on Spark and Compression Ignition Aviation EngineFuels.Current edition approved May 15,2012.Published November 2012.DOI:10.1520/D779612.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 response factors are determined by analyzing prepared stan-dards with the concentrations similar to those encountered inthe sample.5.Significance and Use5.1 The presence of impurities in ETBE product can have adeleterious effect upon the value of ETBE as a fuel additive.Oxygenate and olefin contents are of primary concern.This testmethod provides a knowledge of the composition of ETBEproduct.This is useful in the evaluation of process operationscontrol,in the valuation of the product,and for regulatorypurposes.6.Interferences6.1 Cyclopentane and 2,3-dimethylbutane have been ob-served to co-el