1、Designation: D 2384 83 (Reapproved 2004)An American National StandardStandard Test Methods forTraces of Volatile Chlorides in Butane-Butene Mixtures1This standard is issued under the fixed designation D 2384; the number immediately following the designation indicates the year oforiginal adoption or,
2、 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 These test methods cover the determination of the totalvolatile organic chlorid
3、es in concentrations from 10 to 100ppm in butane-butene mixtures. The amperometric finish is notdirectly applicable in the presence of other substances thatcombine with silver ion or oxidize chloride ion in dilute acidsolution. Bromides, sulfides, ammonia, tobacco smoke, andmore than 25 g of hydroge
4、n peroxide in the test solutioninterfere in the spectrophotometric procedure.1.2 Dissolved sodium chloride is not quantitatively deter-mined using these test methods.1.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard does not purport to address all of thesafety con
5、cerns, 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. Specific warningstatements are given in Sections 5, 8, 11, 14, 19, andAnnexA1.2.
6、 Referenced Documents2.1 ASTM Standards:2D 329 Specification for AcetoneD 1266 Test Method for Sulfur in Petroleum Products(Lamp Method)3. Summary of Test Methods3.1 Combination Test MethodsEither the lamp or oxy-hydrogen test method may be used for combustion.NOTE 1Lamp combustion is readily applic
7、able to multiple testing.Although an oxy-hydrogen burner does not lend itself to multiple testing,it affords much more rapid analysis for a single sample than does the lampcombustion.3.1.1 Lamp CombustionThe sample is burned in an atmo-sphere of carbon dioxide and oxygen or in purified air; thehalog
8、en-containing combustion products are absorbed in dilutesodium carbonate solution.3.1.2 Oxy-Hydrogen CombustionThe sample is burned inan oxy-hydrogen atomizer burner, and the combustion productsare absorbed in a dilute solution of sodium carbonate.3.2 FinishesEither the amperometric titration or spe
9、ctro-photometric finish may be used for the chloride ion determi-nation.3.2.1 Amperometric TitrationThe chloride ion in aqueoussolution is titrated amperometrically with standard silver ni-trate solution, using a saturated calomel electrode as referenceelectrode. The diffusion currents are plotted a
10、gainst the corre-sponding volumes of silver nitrate solution used; the end pointis taken as the intersection of the two straight-line portions ofthe curve.3.2.2 Spectrophotometric FinishChloride ion in the ab-sorber solution is determined by reaction with mercuric thio-cyanate to release thiocyanate
11、, which forms a reddish orangecomplex with Fe+. The intensity of the color is measured at460 nm with a spectrophotometer or filter photometer.4. Significance and Use4.1 These test methods are used to determine trace amountsof volatile chlorides in butane-butene mixtures. Such informa-tion is valuabl
12、e in cases where chloride is deleterious in the useof this product; also, chloride contributes to corrosion prob-lems in processing units in instances where further processingof this material is involved.5. Purity of Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Un
13、less 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.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficientl
14、y high purity to permit its use without lessening theaccuracy of the determination.1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and are the direct responsibility of Subcommit-tee D02.D0 on Hydrocarbons for Chemical and Special Uses.Current
15、edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1965. Last previous edition approved in 2000 as D 2384 83 (2000)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
16、volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent 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
17、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.5.2 References to
18、water shall be understood to meanchloride-free distilled or deionized water.5.3 (WarningIn view of the common occurrence ofchloride in reagents and laboratory air, special care must betaken during preparation and storage of reagents to avoidcontamination. They should be isolated from other reagentsa
19、nd used solely for these methods.Ablank determination mustbe performed each time a reagent is changed to ensure that itis not contaminated with chloride.It is also imperative that all glassware used in this determi-nation be cleaned thoroughly and rinsed four times withchloride-free distilled or dei
20、onized water. Utmost caution mustbe taken during the analysis to prevent contamination fromchlorides.)6. Sampling6.1 Steam and dry a 10 to 25-mL corrosion-resistant metalsample cylinder having a 450-psi (3100 kPa) working pressureand equipped with a needle valve outlet at each end.6.2 Pressure the p
21、repared cylinder with dry hydrogen to 20psig (137.5 kPa gage) to afford a gas cushion preventingrupture due to liquid expansion on increase of temperature.6.3 Obtain a liquid sample from the purged sample line,filling the upright cylinder through the bottom needle valve,keeping the top valve closed.
22、 Do not purge the sample cylinder.LAMP COMBUSTION TEST METHOD7. Apparatus7.1 ASTM Lamp AssemblyUse the apparatus specified inTest Method D 1266, including the liquefied petroleum gasburner assembly.8. Reagents8.1 Use the necessary reagents and materials specified inTest Method D 1266, in addition to
23、 the absorber solution asdescribed in 8.3.8.2 Hydrogen (WarningExtremely flammable (liquefied)gas under pressure. See Annex A1.1.)8.3 Sodium Carbonate Absorbent (2 g/L) Dissolve 2.0 gof anhydrous sodium carbonate (Na2CO3) in water and diluteto a litre with water.9. Procedure9.1 Prepare the combustio
24、n apparatus as described in Sec-tion 7 of Test Method D 1266, Preparation of Apparatus, using35 mL of Na2CO3solution to charge the absorber.9.2 Weigh the vessel containing the sample to the nearest0.1 g. Support the sample vessel in an upright position so thatthe sample is burned from the gaseous ph
25、ase. Connect thesample vessel to the auxiliary corrosion-resistant regulatingvalve by means of corrosion-resistant metal tubing (Fig. 1)(Note 2). Connect the bottom valve of the sample vessel to theregulated hydrogen supply. By means of short lengths ofchloride-free rubber tubing, connect the auxili
26、ary valve outletto the side inlet of the gas burner and the lower inlet of the gasburner (Test Method D 1266,AnnexA3,Apparatus Detail, Fig.5) to the burner manifold.NOTE 2For steady burning, it may be necessary to surround theauxiliary valve with a heat-exchanger system. A convenient means iswinding
27、 insulated heating wire, having a resistance of 40 to 60 V, aroundthe auxiliary valve and connecting it to a suitable rheostat.Another meansis to place the regulating valve in a suitable metal beaker and cover thevalve body with water maintained at 60 to 80C.9.3 Open the valve on the sample vessel;
28、then open theauxiliary valve to allow a small stream of vapor to escape.Quickly light the burner. Adjust the flow of CO2-O2mixtureand the sample so that the flame is approximately 35 mm highand clear blue in color; this color is reached just beyond thepoint at which a yellow color shows at the tip o
29、f the flame.Insert the burner into the chimney and readjust the flame ifnecessary. When the sample has burned almost to completion,open the valve on the bottom of the sample vessel and flush theresidual sample from the cylinder chamber by passing hydro-gen through the bottom valve for several minute
30、s.9.4 When all of the residual material has been flushed fromthe sample vessel, turn off the hydrogen and close the valves onthe sample vessel. Disconnect the hydrogen flushing line andFIG. 1 Diagrammatic Sketch of Butane-Butene Heat Exchange SystemD 2384 83 (2004)2the line to the heated auxiliary v
31、alve and weigh the samplevessel to the nearest 0.1 g. Draw the combustion atmospherethrough one absorber of a set to serve as a blank on the purityof this atmosphere. Rinse the chimneys and spray traps withwater and add the rinsings to the absorbers.9.5 Proceed in accordance with either Section 16 o
32、r 21.OXY-HYDROGEN COMBUSTION TEST METHODALTERNATIVE TEST METHOD10. Apparatus10.1 Oxy-Hydrogen Burner4A flow diagram of a typicalapparatus is shown in Fig. 2. The apparatus shall consist ofthree parts: atomizer-burner, combustion chamber, and receiverwith spray trap. A blowout safety port in the comb
33、ustionchamber is desirable. The remainder of the apparatus shallconsist of a steel support stand with the necessary needlevalves and flow meters for precise control of air, oxygen,hydrogen, and vacuum.10.2 Vacuum Pump, having a capacity of at least 1200 L/h,and protected from corrosive fumes by suit
34、able traps.11. Reagents and Materials11.1 Hydrogen (WarningExtremely flammable (lique-fied) gas under pressure. See Annex A1.1.)11.2 Oxygen (WarningOxygen vigorously acceleratescombustion. See Annex A1.2.)11.3 Sodium Carbonate, Absorbent (2g/L)See 8.3.12. Procedure12.1 Follow the manufacturers instr
35、uctions for preparingand operating the apparatus. Place 50 mL of the Na2CO3absorbent in the absorber. Burn all of the sample from the gasphase of the cylinder (Fig. 1)(WarningExtremely flam-mable (liquefied) gas under pressure. See Annex A1.1.). Flushthe residual gases from the cylinder chamber by p
36、assinghydrogen through the bottom valve for several minutes, burn-ing the flushed gases.)12.2 When combustion is completed, rinse all water-cooledportions of the apparatus and the spray trap with a spray ofwater. Collect all rinsings in the absorbent.12.3 Proceed in accordance with either Section 16
37、 or 21.12.4 Prepare a blank by placing 50 mL of the Na2CO3absorbent in the absorber. Operate the apparatus for the sameperiod of time, under the same conditions that were used forthe combustion of the sample, but without a sample and thesample inlet closed to the atmosphere. Burn approximately thesa
38、me volume of hydrogen as was used to flush the samecylinder. When combustion of the hydrogen is complete, rinseall water-cooled portions of the apparatus and the spray trapwith a spray of water. Collect all rinsings in the absorbent.Proceed as in 12.3.AMPEROMETRIC TITRATION FINISH13. Apparatus13.1 P
39、otentiometer-Galvanometer Assembly, capable of ap-plying a cell potential up to 3 V with an accuracy of 1 % of fullscale, and capable of indicating the cell current by means of agalvanometer having a sensitivity of 0.005 to 0.008 A/mmscale division. A multiposition galvanometer shunt for adjust-ment
40、 of current measurement sensitivity should also be pro-vided; shunt ratios to give sensitivities of approximately 0.05to 0.08, and 0.10 to 0.16 A/mm should be included.13.2 Titration AssemblyAn apparatus similar to thatshown in Fig. 3, consisting of a rotating (600 rpm) platinumelectrode, a saturate
41、d calomel reference electrode with saltbridge, a means of blanketing the solution with nitrogen, and aholder for a 10-mL buret.13.3 Calomel Electrode, constructed as shown in Fig. 3.13.4 Platinum Electrode, rotating-hook type. A suitableelectrode may be constructed as follows: Seal a platinum wire0.
42、03 to 0.05 in. (0.76 to 1.3 mm) in diameter and 0.75 to 1.0 in.(19.1 to 25.4 mm) long into the end of a 6-mm outside diametersoft glass tube that has been shaped into a stirrer blade. Bendthe extending platinum wire upwards at its midpoint to form anangle of 90. Place a few drops of mercury in the g
43、lass tube andmake electrical contact between the mercury and the connec-tion on the amperometric titrator with a piece of copper wire(insulate the exposed wire to prevent shorting).4The Wickbold Burner Apparatus obtainable from the Atlas Instrument Co.,8902 E. 11th St., Tulsa, OK, or the Richfield B
44、urner Apparatus obtainable from theGreiner Glass Blowing Laboratories, 3604 E. Medford St., LosAngeles, CA90034,has been found suitable for this purpose. If you are aware of alternative suppliers,please provide this information to ASTM International Headquarters. Your com-ments will receive careful
45、consideration at a meeting of the responsible technicalcommittee1, which you may attend.1Atomizer-burner 4Three-way stopcock2Sample tube 5Absorber3Combustion chamber 6Spray trapFIG. 2 Flow Diagram of a Typical Oxy-Hydrogen CombustionApparatusD 2384 83 (2004)313.5 BuretA 10-mL semi-micro buret, with
46、the tip con-structed so as to be able to dip below the surface of the solutionbeing titrated.14. Reagents14.1 Acetone (99.5 %) (WarningExtremely flammable.Vapor may cause fire. See Annex A1.3.)Refined acetoneconforming to Specifications D 329.14.2 Agar SolutionDissolve2gofagar-agar powder in100 mL o
47、f hot water (80 to 100C) containing 20 g ofpotassium nitrate (KNO3).14.3 Bromthymol Blue Indicator Solution Dissolve 0.10 gof the solid indicator in 100 mL of hot water, cool, and add 1mL of chloroform as a preservative. Discard the solution whenit is 1 week old.NOTE 3Remove possible objectionable a
48、mounts of chloride by pass-ing the solution through an ion-exchange resin in the hydroxyl form.Neutralize the resulting alkaline solution to the bromthymol blue end pointby titration with HNO3(3 + 97).14.4 Chloride, Standard Solution (10 g Cl/mL)Dilute asuitable volume of 1 + 10 assayed hydrochloric
49、 acid to obtaina solution containing 10 g Cl/mL.14.5 Gelatin Solution (10 g/L)Dissolve1gofgelatin in100 mL of hot water and add 1 mL of chloroform as apreservative. Discard the solution when it is 1 week old.14.6 Hydrogen Peroxide SolutionPrepare by diluting 1volume of concentrated hydrogen peroxide solution (H2O2,30 %) with 4 volumes of water. Store in a dark-coloredglass-stoppered bottle.14.7 Mercury-Calomel MixturePrepare a mixture of mer-cury and calomel (mercurous chloride, Hg2Cl2) by vigorouslyshaking 10 g of calomel with 50 g
