1、Designation: D5350 95 (Reapproved 2012)Standard Test Method forDetermination of Organically Combined Sulfuric Anhydrideby Titration, Test Method A1This standard is issued under the fixed designation D5350; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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 organi-cally combined sulfuric anh
3、ydride existing in a sample ofsulfated oil by boiling the sample with sulfuric acid anddetermining the acidity of the reaction mixture. This testmethod is applicable only to oils that split off their combinedSO3upon boiling with mineral acids and that do not containcompounds that cannot be accuratel
4、y titrated in water solutionwith methyl orange as the indicator. This test method wasderived from Test Methods D500, Sections 15 through 19.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are provided forinformation only.1.3 This standard does not
5、 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
6、:2D500 Test Methods of ChemicalAnalysis of Sulfonated andSulfated Oils3. Significance and Use3.1 This test method is intended for the determination oforganically combined sulfuric anhydride in sulfated oils.4. Apparatus4.1 The apparatus required consists of a glass flask providedwith a glass stopper
7、 and an air condenser. The connectionbetween the flask and the condenser shall be a ground joint.Perforated glass beads shall be used to prevent bumping.4.1.1 Flask, an Erlenmeyer flask (Fig. 1) made of borosili-cate glass, having a capacity of approximately 300 mL andprovided with a glass stopper.4
8、.1.2 CondenserThe condenser required consists of aglass tube, 915 mm (36 in.) in length, and 8 mm (516 in.) inoutside diameter. The lower end of the tube shall be flared andground to fit the mouth of the Erlenmeyer flask.4.1.3 Glass Beads, perforated glass beads, made of chemi-cally resistant glass,
9、 approximately 4 mm (532 in.) in diameter.Before using, the glass beads shall be boiled thoroughly inseveral portions of water or until the wash water reacts neutralto methyl orange indicator.5. Reagents5.1 Ethyl Ether.5.2 Methyl Orange Indicator Solution (1 g/L)Dissolve 0.1g of methyl orange in 100
10、 mL of water.5.3 Sodium Chloride (NaCl), solid.5.4 Sodium Hydroxide, Standard Solution (1 N)Accurately prepare and standardize a 1 N sodium hydroxide(NaOH) solution. Express the strength or concentration of thesolution as milligrams of KOH per millilitre; 1 mL of 1 NNaOH solution is equivalent to 56
11、.1 mg of KOH.5.5 Sodium Hydroxide, Standard Solution (0.5 N)Accurately prepare and standardize a 0.5 N NaOH solution.Express the strength of the solution as milligrams of KOH permillilitre; 1 mL of 0.5 N NaOH solution is equivalent to 28.05mg of KOH.5.6 Sulfuric Acid, Standard (0.5 N)Accurately prep
12、areand standardize a 0.5 N sulfuric acid (H2SO4) solution. Expressthe strength of the solution as milligrams of KOH per millilitre;1mLof0.5N H2SO4is equivalent to 28.05 mg of KOH.5.7 Sulfuric Acid (1+19)Carefully mix one volume ofconcentrated sulfuric acid (H2SO4, sp gr 1.84) into 19 volumesof water
13、 while stirring.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.08 on Fats and Oils. This testmethod was developed in cooperation with the American Leather Chemists Assn.(Method H 421957).Current edition approved April
14、1, 2012. Published April 2012. Originallyapproved in 1993. Last previous edition approved in 2006 as D5350 95(2006).DOI: 10.1520/D5350-95R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volu
15、me information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Procedure6.1 The procedure consists of two determinations: namely,(1) the alkalinity of the sample, de
16、signated as A, and (2) theincrease in acidity after boiling the sample with sulfuric acid,designated as F.6.1.1 Alkalinity, ADissolve 10 g of the sample in 100 mLof water in the 300-mL glass-stoppered Erlenmeyer flask,warming to obtain solution, if necessary. After cooling, add 30g of NaCl, 25 mL of
17、 ether, and five drops of methyl orangeindicator solution; then add 0.5 N H2SO4with frequent butgentle shaking until the mixture is slightly acid. Shake thecontents of the flask vigorously, and complete the titration byadding first 0.5 N NaOH solution several drops at a time untilthe solution is alk
18、aline and then the acid one or two drops at atime until the end point is reached. Shake the solutionvigorously after each addition of reagent. Drain burets for 3min before taking readings. Calculate the alkalinity, A,asfollows:A 5 B 3 D! 2 C 3 E!#/W (1)where:A = total alkalinity, mg of KOH/g,B = mil
19、lilitres of H2SO4required for titration of thesample,C = millilitres of NaOH solution required for titration ofthe sample,D = strength of H2SO4, mg of KOH/mL,E = strength of NaOH solution, mg of KOH/mL, andW = weight of sample, g.6.1.2 Increase in Acidity upon Boiling, FWeigh 10 g ofthe sample into
20、the Erlenmeyer flask and boil under the aircondenser with H2SO4(1+19) for 112 h or until both the oil andwater layers are perfectly clear, using glass beads to preventbumping. The volume of H2SO4added shall be sufficient toneutralize the total alkalinity, A, of the sample plus 25 mL inexcess. Regula
21、te the heating so that the solution boils rathervigorously but with very little evaporation taking place. At theend of the heating period allow the contents to cool, wash thecondenser with a spray of water from a wash bottle, anddisconnect the condenser.Add 30 g of NaCl, 25 mL of ether, 50mL of wate
22、r, and five drops of indicator solution and titrate thesolution with 1 N NaOH solution to the same end point as inthe total alkalinity titration, 6.1.1. During the titration stopperthe flask frequently and shake the contents of the flaskthoroughly. Drain the burets for 3 min before readings aretaken
23、.NOTE 1Reserve the titrated solution for the subsequent determinationof total desulfated fatty matter (Section 29 to 32 of Test Methods D500).6.1.2.1 Make a blank determination simultaneously with thesample, using the same amount and strength of the H2SO4,approximately the same weight of glass beads
24、, and heating andtitrating under the same conditions as the sample.6.1.2.2 Calculate the increase in acidity upon boiling, F,asfollows:F 5 S 2 B!N/W (2)where:F = increase in acidity (Note 2) upon boiling, mg ofKOH/g,S = millilitres of NaOH solution required for titration ofthe sample,B = millilitres
25、 of NaOH solution required for titration ofthe blank,N = strength of NaOH solution, mg of KOH/mL, andW = weight of sample, g.NOTE 2The increase in acidity, F, may be negative, in which caseretain the sign obtained from the equation in Section 7.7. Calculation7.1 Calculate the percentage of organical
26、ly, combined sul-furic anhydride as follows:Organically combined sulfuric anhydride, % 5 0.1426A 1 F! (3)where:0.1426 = one tenth of the molecular ratio of SO3:KOH,A = total alkalinity, mg of KOH/g, andF = increase in acidity upon boiling, mg of KOH/g.= Retain the sign of F as obtained in 6.1.2.8. P
27、recision and Bias8.1 Although this test method is widely used, precision andbias information is not available at this time.9. Keywords9.1 leather; sulfated oils; sulfuric anhydride; titrationFIG. 1 Apparatus for Determination of Organically CombinedSulfuric Anhydride, Test Method AD5350 95 (2012)2AS
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31、 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 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D5350 95 (2012)3
