1、Designation: D4423 10Standard Test Method forDetermination of Carbonyls in C4Hydrocarbons1This standard is issued under the fixed designation D4423; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r 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 carbonyls(ketones and aldehydes) in C4hydrocarbons. This test methodwas tested on polymerizatio
3、n-grade 1,3-butadiene.1.2 The applicable range for this test method is 0 to50 mg/kg carbonyls calculated as acetaldehyde.1.3 Other C4hydrocarbons and their mixtures besidespolymerization-grade 1,3-butadiene could be tested using thissame test method. However, the precision section of this testmethod
4、 covers only carbonyls in applicable range as listed in1.2, as found in polymerization-grade 1,3-butadiene.1.4 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous t
5、o health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information. Users should be aware that selling
6、mercuryand/or mercury containing products into your state or countrymay be prohibited by law.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, as
7、sociated 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:2D484 Specification for Hydrocarbon Dry Cleaning Sol-ven
8、ts3D1193 Specification for Reagent WaterE1 Specification for ASTM Liquid-in-Glass Thermometers3. Summary of Test Method3.1 A measured amount of sample is added to an alcoholichydroxylamine hydrochloride solution that has been adjustedto a given coloration using either alcoholic acid or base. Thecarb
9、onyls will react with the hydroxylamine hydrochloridereleasing an equivalent amount of hydrochloric acid which isthen back-titrated to the original coloration.Ablank containingonly methanol and sample is titrated and the samples resultsare calculated using the blank adjustment. Results are reporteda
10、s milligrams per kilogram carbonyls as acetaldehyde.4. Significance and Use4.1 The determination of the carbonyl content ofpolymerization-grade 1,3-butadiene is necessary, since in somepolymerization reactions, the presence of carbonyls in excessover some specified amount can have a deleterious effe
11、ct uponthe polymer properties or the reaction itself, or both.5. Apparatus5.1 Bunsen ValvesAdevice constructed so that when usedwith an Erlenmeyer flask, the sample vapors can exit the flaskwhile protecting the flasks liquid contents. See Fig. 1 fordetails.5.2 Cooling CoilPrepare a cooling coil by w
12、inding about10 to 15 cm of seamless copper tubing (about 6-mm diameter)on a short length of pipe (about 1.5 to 2.0-cm diameter),allowing sufficient length of tubing at the end of the coil toconnect it to the sample source. Attach a valve at a point thatwould not extend more than 8 cm above the surfa
13、ce of thecooling bath liquid. To the valve, attacha6to8cmlengthpiece of tubing bent downward so that the hydrocarbon liquidcan be directed into the receiving container.5.3 Dewar FlaskThe Dewar flask must be of sufficientvolume to completely immerse the main portion of the cooling1This test method is
14、 under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.D0.04 on C4 Hydrocarbons.Current edition approved May 1, 2010. Published June 2010. Originallyapproved in 1984. Last previous edition approved in 2006 as D442300(2006
15、).DOI: 10.1520/D4423-10.2For 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.3Withdrawn. The last approved version
16、 of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.coil except for the extremities necessary for receiving anddelivering the sample through the coil.5.4 Erlenmeyer Flasks, 250-mL
17、 capacity.5.5 Volumetric Flasks, 1-L capacity. These flasks should beClass A glassware.5.6 Graduated Cylinders100-mL capacity, glass cylin-ders, graduated in 1 or 2-mL divisions.5.7 Microburets, 2.00 or 5.00-mL capacity. The microburetsshould be ClassAglassware with 0.01 or 0.02-mL divisions orless.
18、 It is advisable to have the burets tip end equipped with asyringe needle to dispense very small drops of titrant.5.8 Sample CylindersThese should be of sufficient vol-ume to give the required amount of sample for testing.Stainless steel cylinders equipped with needle valves should beused. It is sug
19、gested that a 500-mL-capacity cylinder be theminimum size to be used for butadiene.5.9 ThermometerFor observing temperatures below45C. The Low Cloud and Pour Point Thermometer, con-forming to the requirements for ASTM Thermometer 6C, asprescribed in Specification E1, is satisfactory. Thermometer 6Ch
20、as a range from 80 to +20C. Temperature measuringdevices that cover the temperature range of interest, such as theASTM 1C thermometer, or liquid-in-glass thermometers, ther-mocouples, or platinum resistance thermometers that provideequivalent or better accuracy and precision may be used.6. Reagents
21、and Materials6.1 Purity of ReagentsReagent grade chemicals should beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grade
22、s may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II reagent waterconforming to Specific
23、ation D1193.6.3 Alcoholic Hydrochloric Acid (0.05 N)Dilute 4.2 mLof concentrated hydrochloric acid (WarningPoison. Corro-sive. May be fatal if swallowed. Liquid and vapor cause severeburns. Harmful if inhaled.) to volume with anhydrous methanolin a 1-L volumetric flask. Use the alcoholic 0.05 N pota
24、ssiumhydroxide solution to standardize the HCl solution.6.4 Alcoholic Hydroxylamine HydrochlorideDissolve35.0 g of hydroxylamine hydrochloride (WarningMay beirritating to skin, eyes, or mucous membranes. Harmful ifinhaled.) in 3.5 L of anhydrous methanol. (WarningFlammable. Vapor harmful. May be fat
25、al or cause blindness ifswallowed or inhaled. Cannot be made nonpoisonous.)6.5 Alcoholic Potassium Hydroxide (0.05 N)Dissolve3.3 g of potassium hydroxide in anhydrous methanol.(WarningCorrosive. Can cause severe burns or blindness.Evolution of heat produces a violent reaction or eruption upontoo rap
26、id mixture with water.) Make to volume with methanolin a 1-L volumetric flask. Standardize against a primarystandard, potassium acid phthalate.6.6 Dry Ice (Carbon Dioxide Solid)(WarningExtremely cold (78.5C). Liberates heavy gas which maycause suffocation. Contact with skin causes burns or freezing,
27、or both. Vapors may react violently with hot magnesium oraluminum alloys.)6.7 Stoddard SolventConforming to the specificationlisted in Specification D484.(WarningCombustible. Vaporharmful.)6.8 Thymol Blue IndicatorDissolve 0.04 g of thymol bluein 100 mL of anhydrous methanol. (WarningFlammable.Vapor
28、 harmful. May be fatal or cause blindness if swallowed orinhaled. Cannot be made nonpoisonous.)7. Preparation of Apparatus7.1 Dry Ice-Stoddard Solvent Bath Add a sufficient quan-tity of Stoddard solvent into the Dewar flask to ensure that thecooling coil will be submerged in the liquid plus dry ice
29、(solidCO2). (WarningSee 6.6 and 6.7.) Carefully add sufficientdry ice to the Stoddard solvent to obtain a temperature of atleast 50C. (WarningGreat care must be taken during thisstep. Do not add the dry ice all at once, but in small pieces,especially at the beginning. Wear protective gloves and ad-e
30、quate eye protection to prevent any contact with the extremelycold materials.) Attach the sample cylinder containing thebutadiene (WarningExtremely flammable gas under pres-sure. May form explosive peroxides upon exposure to air.Harmful if inhaled. Irritating to eyes, skin, and mucousmembranes.) to
31、the cooling coil and immerse the coil into theliquid. Support the sample cylinder in a cylinder rack or usinga ring stand and appropriate clamps. Be sure the coil ispositioned so that the delivery tip is free to dispense liquidbutadiene into the Erlenmeyer flasks.After each use, be sure toclean the
32、coils interior with methanol. DO NOT USE AC-ETONE.4Reagent 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., Poo
33、le, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 ApparatusD4423 1028. Procedure8.1 Prepare a sample flask by pouring 50 mL of alcoholichydroxylamine hydrochloride into a 250-mL Erlenmeyer flask.8.2 Prepare a f
34、lask for use as a sample blank by pouring50 mL of methanol into a 250-mL Erlenmeyer flask.8.3 Add about 0.5 mL of thymol blue indicator solution toeach flask.8.4 Carefully add 0.05 N alcoholic KOH or alcoholic HCl toeach flask until matching colors are obtained. The desired coloris a yellow color wi
35、th a slight, but distinct, orange coloration.It is important that this orange color is present at this point ofthe test. If the color is more yellow at this point, it would beeasy to obtain a result of less than 1 mg/kg carbonyls on asample containing over 100 mg/kg of carbonyls.8.5 Stopper the flas
36、ks with the Bunsen valves. (This keepsthe CO2vapor out of the flasks). Set the flasks on some crusheddry ice for a few minutes to cool the liquid contents. The colorin the flasks may turn more yellow when cold, but this is notsignificant at this point. From this step forward, all operationsmust be c
37、arried out in a well-ventilated hood.8.6 Cool a 100-mL graduated cylinder by holding it in thecooling bath for a few seconds. Then, when it is cold, collect100 6 1 mL butadiene into the graduated cylinder. Quickly,using a clean thermometer, measure the samples temperatureto the nearest 1C. Record th
38、is temperature as “T” for use laterto obtain the sample weight. Pour this sample into the sampleflask containing the alcoholic hydroxylamine hydrochloridesolution. Replace the Bunsen valve on the flask and set aside.Again, collect 100 6 1 mL of sample into the graduatedcylinder. Pour this sample int
39、o the sample blank flask contain-ing only the methanol. Replace the Bunsen valve and set aside.8.7 Sample and sample blank can be titrated after 15 minwhile cold butadiene is in the flasks. If done, be careful toavoid vigorous agitation because some of the contents may boilover and be lost. It is ad
40、visable to allow as much of thebutadiene as possible to evaporate before titration begins.8.8 Titrate the sample flasks contents back to the originalcoloration, as described in 8.4, by using the alcoholic KOH.Record this value as “A.” Set the flask aside in the hood for5 min before pouring out the c
41、ontents. If it turns red, thecarbonyl concentration may be high or there is contaminationin the flask. Continue the titration until the flasks contents willnot turn red after standing 5 min.8.9 Titrate the sample blank flasks contents. If the solutionis red, use the standard KOH solution. If it is y
42、ellow, use thestandard HCl solution. In either case, unless the sample blankscontents are still at the original coloration, titrate with theappropriate titrant back to the same, original coloration asdescribed in 8.4. Record this value as “E.”9. Calculation9.1 Calculate as follows when the sample ha
43、s no free acid orfree base:mg/Kg carbonyls as acetaldehyde!5A 3 Nb 3 44050/ V 3 D(1)where:A = alcoholic KOH titration, mL,Nb = normality of KOH solution,V = sample volume, mL, andD = butadiene density at temperature T (found by usingTable 1).9.2 Calculate as follows when the sample has free acid:mg/
44、Kg carbonyls as acetaldehyde!5A Bb! 3 Nb 3 44050/ V 3 D(2)where:Bb = alcoholic KOH used for the sample blank, mL.9.3 Calculate as follows when the sample has free base:mg/Kg carbonyls as acetaldehyde!5A3 Nb! 1 Ba 3 Na!3 44050/ V 3 D (3)where:Na = normality of alcoholic HClBa = alcoholic HCl used for
45、 the sample blank, mL10. Precision and Bias10.1 PrecisionThe precision of this test method as deter-mined by statistical examination of interlaboratory results is asfollows:10.1.1 RepeatabilityThe difference between two test re-sults obtained by the same operator with the same apparatusunder constan
46、t operating conditions on identical test materialwould, in the long run, in normal and correct operation of thetest method, exceed the following value in only one case intwenty, where X = the average of the two test results:14%ofX10.2 ReproducibilityThe difference between two singleand independent r
47、esults obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the following value in only one case in twenty,where X = average of two test results:88%ofX10.3 BiasSince there is
48、 no accepted reference material fordetermining the bias for the procedure in this test method formeasuring carbonyls, no statement on bias is being made.11. Keywords11.1 butadiene; C4hydrocarbons; carbonyls; titrationTABLE 1 Density of Butadiene at Various TemperaturesNOTEThese data may be used in a
49、 graphical manner for betterinterpolation between data points.Temperature, C Density, g/mL45 0.695840 0.690335 0.684830 0.679325 0.673720 0.668115 0.662510 0.65685 0.65100 0.6452D4423 103ASTM International takes no position respecting the validity of any patent rights asserted 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 responsi
