1、Designation: D 4423 00 (Reapproved 2006)An American National StandardStandard Test Method forDetermination of Carbonyls In C4Hydrocarbons1This standard is issued under the fixed designation D 4423; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e 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 carbonyls(ketones and aldehydes) in C4hydroca
3、rbons. This test methodwas tested on polymerization-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.
4、 However, the precision section of this testmethod covers only carbonyls in applicable range as listed in1.2, as found in polymerization-grade 1,3-butadiene.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard d
5、oes 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 St
6、andards:2D 484 Specification for Hydrocarbon Dry Cleaning Sol-vents3D 1193 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 adjusted
7、to a given coloration using either alcoholic acid or base. Thecarbonyls 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 resul
8、tsare calculated using the blank adjustment. Results are reportedas 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 carbony
9、ls in excessover some specified amount can have a deleterious effect 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.
10、 See Fig. 1 fordetails.5.2 Cooling CoilPrepare a cooling coil by winding 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 va
11、lve at a point thatwould not extend more than 8 cm above the surface 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 comp
12、letely immerse the main portion of the coolingcoil except for the extremities necessary for receiving anddelivering the sample through the coil.5.4 Erlenmeyer Flasks, 250-mL capacity.5.5 Volumetric Flasks, 1-L capacity. These flasks should beClass A glassware.5.6 Graduated Cylinders100-mL capacity,
13、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. It is advisable to have the burets tip end equipped with asyringe needle to dispense very small drops of titrant.5.8 Sample Cy
14、lindersThese 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 suggested that a 500-mL-capacity cylinder be theminumum size to be used for butadiene.5.9 ThermometerFor observing temperatures be
15、low45C. The Low Cloud and Pour Point Thermometer, con-forming to the requirements for ASTM Thermometer 6C, as1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.D0.04 on C4Hydrocarbons.Current editi
16、on approved July 1, 2006. Published August 2006. Originallyapproved in 1984. Last previous edition approved in 2000 as D 4423 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
17、on, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.prescribed in Specification E1, is satisfactory. Thermometer6C has a range from 80 to +20C.6. Reagents and
18、 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 grades m
19、ay 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 Specificati
20、on D 1193.6.3 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 potass
21、iumhydroxide solution to standarize 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 fatal
22、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 rapid
23、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,or
24、both. Vapors may react violently with hot magnesium oraluminum alloys.)6.7 Stoddard SolventConforming to the specificationlisted in Specification D 484.(WarningCombustible. Vaporharmful.)6.8 Thymol Blue IndicatorDissolve 0.04 g of thymol bluein 100 mL of anhydrous methanol. (WarningFlammable.Vapor h
25、armful. 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 (s
26、olidCO2). (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-equ
27、ate 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 th
28、e 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 co
29、ils interior with methanol. DO NOT USE AC-ETONE.8. Procedure8.1 Prepare a sample flask by pouring 50 mL of alcoholichydroxylamine hydrochloride into a 250-mL Erlenmeyer flask.8.2 Prepare a flask for use as a sample blank by pouring50 mL of methanol into a 250-mL Erlenmeyer flask.8.3 Add about 0.5 mL
30、 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 with a slight, but distinct, orange coloration.It is important that this orange color is present at this point o
31、fthe 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 flasks with the Bunsen valves. (This keepsthe CO2vapor out of the flasks). Set the flasks on some crusheddry ice f
32、or 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 carried out in a well-ventilated hood.8.6 Cool a 100-mL graduated cylinder by holding it in thecooling bath for
33、 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 temperature4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of
34、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.FIG. 1 ApparatusD 4423 00 (2006)2to the nearest 1C. Rec
35、ord this 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 samp
36、le into 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
37、 is advisable 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
38、 the contents. 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 i
39、t is yellow, 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 sam
40、ple has 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 ac
41、id:mg/Kg carbonyls as acetaldehyde!5A Bb! 3 Nb 3 44050/ V 3 D(2)whereBb = 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 use
42、d for 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 co
43、nstant 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 independ
44、ent results 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 the
45、re is 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
46、 in a 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 0.6452D 4423 00 (2006)3ASTM International takes no position respecting the validity of any patent rights asserted in connec
47、tion 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 responsibility.This standard is subject to revision at any time by the responsib
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49、sideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (
