ASTM_D_1832_-_87_1999.pdf

Designation:D 1832 87(Reapproved 1999)An American National StandardTechnical Association of Pulpand Paper Industry Standard Method T 659 su-67Standard Test Method forPeroxide Number of Petroleum Wax1This standard is issued under the fixed designation D 1832;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the perox-ide number of petroleum wax.1.2 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.Terminology2.1 Definition:2.1.1 peroxide numberthe milliequivalents of constituentsper 1000 g of wax that will oxidize potassium iodide.3.Summary of Test Method3.1 Aquantity of sample is dissolved in carbon tetrachlorideand acidified with acetic acid solution.A solution of potassiumiodide is added and,after a reaction period,the solution istitrated with sodium thiosulfate solution to the end pointindicated by the color change of added starch solution.4.Significance and Use4.1 The magnitude of the peroxide number is an indicationof the quantity of oxidizing constituents present.Deteriorationof petroleum wax results in the formation of peroxides andother oxygen-carrying compounds.The peroxide number mea-sures those compounds that will oxidize potassium iodide.5.Apparatus5.1 Iodine Flask,borosilicate glass,250-mL capacity,glass-stoppered.6.Reagents and Materials6.1 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 Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.2Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean distilled water or water ofequal purity.6.3 Acetic Acid SolutionMix 4 mL of concentrated hydro-chloric acid(HCl,sp gr 1.19)with 996 mL of ACS specialreagent grade glacial acetic acid(CH3CO2H).The acetic acidmust pass the12h test for substances reducing K2Cr2O7.6.4 Carbon Tetrachloride(CCl4).6.5 Potassium Dichromate,Standard Solution(0.1 N)Recrystallize potassium dichromate(K2Cr2O7)twice from anaqueous solution and dry at about 325F(164C)to constantweight.Dissolve 2.452 g of the purified K2Cr2O7in water anddilute to 500 mL in a volumetric flask.6.6 Potassium Dichromate,Standard Solution(0.01 N)Dilute 100 mL of 0.1 N K2Cr2O7solution with water to 1000mL in a volumetric flask.6.7 Potassium Iodide SolutionDissolve 120 g of potas-sium iodide(KI)in 100 mL of water.Discharge any color fromthis solution as follows:put 1 mL of KI solution,50 mL ofwater,and 5 mL of starch solution in a 300-mL flask andblanket with nitrogen or carbon dioxide.If a blue colordevelops,add 0.005 N Na2S2O3solution from a microburetuntil color just disappears.Calculate and add sufficientNa2S2O3solution to the main KI solution to convert all freeiodine to iodide.When starch solution is added to 1 mL of KIsolution a blue color should not develop,but upon the additionof 1 drop of 0.01 N K2Cr2O7solution and 2 drops ofconcentrated hydrochloric acid(HCl,sp gr 1.19),a blue colorshould develop.Store this solution under chloroform by addinga few millilitres to the surface of the liquid.6.8 Sodium Thiosulfate,Standard Solution(0.1 N)Dissolve 12.5 g of sodium thiosulfate(Na2S2O35H2O)and 0.1g of sodium carbonate(Na2CO3)in 500 mL of water.Let stand1This test method is under the jurisdiction of the ASTM Committee D-2 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.10 on Properties of Petroleum Wax.Current edition approved Oct.30,1987.Published December 1987.Originallypublished as D 1832 61 T.Last previous edition D1832 65(1982)e1.2Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.a week or more before using.Standardize against 0.1 NK2Cr2O7solution.Restandardize at intervals frequent enoughto detect changes of 0.0005 in normality.6.9 Sodium Thiosulfate,Standard Solution(0.005 N)Dilute 100 mL of