ASTM D94-07(2017) Standard Test Methods for Saponification Number of Petroleum Products.pdf

1、Designation: D94 07 (Reapproved 2017)Designation: 136S1/98, 136S2/99Standard Test Methods forSaponification Number of Petroleum Products1This standard is issued under the fixed designation D94; the number immediately following the designation indicates the year of originaladoption or, in the case of

2、 revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test me

3、thods cover the determination of theamount of constituents in petroleum products such aslubricants, additives, and transmission fluids that will saponifyunder the conditions of the test.NOTE 1Statements defining this test and its significance when appliedto electrical insulating oils of mineral orig

4、in will be found in Guide D117.Experience has shown that for transformer oils, Test Method D94,modified by use of 0.1 M KOH solution and 0.1 M HCl, is more suitable.1.1.1 Two test methods are described: Method AColorIndicator Titration (Sections 613), and MethodBPotentiometric Titration (Sections 14

5、23).1.2 Because compounds of sulfur, phosphorus, thehalogens, and certain other elements that are sometimes addedto petroleum products also consume alkali and acids, theresults obtained indicate the effect of these extraneous materi-als in addition to the saponifiable material present. Results onpro

6、ducts containing such materials, on used internal-combustion-engine crankcase oils, and on used turbine oilsmust be interpreted with caution.NOTE 2The materials referred to above, which are not normallyconsidered saponifiable matter, include inorganic or certain organic acids,most nonalkali soaps, a

7、nd so forth. The presence of such materialsincreases the saponification number above that of fatty saponifiablematerials for which the test method is primarily intended. The odor ofhydrogen sulfide near the end of the back-titration in the saponificationtest is an indication that certain types of re

8、active sulfur compounds arepresent in the sample. In the case of other reactive sulfur, chlorine, andphosphorus compounds and other interfering materials, no simple indica-tion is given during the test. A gravimetric determination of the actualamount of fatty acids is probably the most reliable meth

9、od for suchcompounds. Test Methods D128 or IP Method 284/86 can be used todetermine fatty acids gravimetrically.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 concerns, if any, associated with its use. It is therespo

10、nsibility 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. For specific hazardstatements, see Sections 6, 7, 8, 10, 15, 16, 17, and 19.1.5 This international standard was developed in accor-dan

11、ce with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Sta

12、ndards:2D117 Guide for Sampling, Test Methods, and Specificationsfor Electrical Insulating Oils of Petroleum OriginD128 Test Methods for Analysis of Lubricating GreaseD1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automati

13、c Sampling of Petroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality Management Systems in Petro-leum Products, Liquid Fuels, and Lubricants TestingLaborato

14、ries2.2 Energy Institute Standards:3IP 136 Method of Test for Saponification Number of Petro-leum ProductsIP 284 Method of Test for Fatty Acids1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and are the direct responsibilityof S

15、ubcommittee D02.06 on Analysis of Liquid Fuels and Lubricants.Current edition approved May 1, 2017. Published July 2017. Originally approvedin 1921. Last previous edition approved in 2007 as D94 07 (2012)1. DOI:10.1520/D0094-07R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org,

16、 orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Institute of Petroleum, 61 New Cavendish St., London, W.I.,England.Available from Energy Institute, 61 New Cavendi

17、sh St., London, WIG7AR, U.K., http:/www.energyinst.org.uk.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established

18、 in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13. Terminology3.1 Definitions:3.1.1 saponification number, nthe number of milligramsof potassium hydroxide cons

19、umed by 1 g of a sample under theconditions of the test.3.1.1.1 DiscussionThe value of the saponification numberin these test methods can be affected by the presence of otheralkali-reactive species, as described in Note 2.3.1.2 saponify, vto hydrolyze a fat with alkali to form analcohol and the salt

20、 of a fatty acid.4. Summary of Test Method4.1 A known mass of the sample is dissolved in a suitablesolvent, such as butanone (methylethylketone), xylenes, orStoddard Solvent, or a combination thereof (WarningExtremely flammable. Vapors can cause flash fire), and isheated with a known amount of alcoh

21、olic potassium hydroxide(KOH). The excess alkali is titrated with standard acid, and thesaponification number is calculated.4.2 The titration end point can be detected either colori-metrically (Method A) or potentiometrically (Method B).5. Significance and Use5.1 Petroleum products can contain addit

22、ives that react withalkali to form metal soaps. Fats are examples of such additives.Also, certain used engine oils, especially from turbine orinternal combustion engines, can contain chemicals that willsimilarly react with alkali. The saponification number ex-presses the amount of base that will rea

23、ct with 1 g of samplewhen heated in a specific manner.This then gives an estimationof the amount of acid present in the sample, that is, any freeacid originally present plus any combined (for example, inesters) that have been converted to metal soaps during theheating procedure.5.2 Saponification nu

24、mbers are also used in setting productspecifications for lubricants and additives.METHOD ACOLOR INDICATOR TITRATION6. Apparatus6.1 Erlenmeyer Flask and Condenser An Erlenmeyerflask, 250 mL or 300 mL capacity, alkali-resistant (see Note 3)and (WarningCauses severe burns; a recognized carcino-gen; str

25、ong oxidizercontact with other material can causefire; hygroscopic ), to which is attached a straight ormushroom-type reflux condenser. The straight-type condenseris fitted to the flask with a ground-glass joint; the mushroom-type condenser must fit loosely to permit venting of the flask.Water reflu

26、x condensers can also be used instead of aircondensers.NOTE 3Do not use scratched or etched Erlenmeyer flasks becauseKOH will react with them. The glassware shall be chemically clean. It isrecommended that flasks be cleaned with chromic acid cleaning solution(Alternatively, Nochromix or similar prod

27、ucts can be used.)6.2 Hot PlateA suitable hot plate heated by either elec-tricity or steam. (WarningThermal hazard; in addition toother precautions, avoid contact with exposed skin.)7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is

28、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.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use

29、without lessening theaccuracy of the determination.NOTE 4Commercially available reagents may be used in place oflaboratory preparations, provided they meet the specifications outlined.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as defin

30、edby Type I, II, or III in Specification D1193.7.3 Alcohol595 % ethanol (WarningFlammable.DenaturedCannot be made nontoxic) (see Note 5) and(WarningFlammable) or 95 % ethanol to which has beenadded 10 % by volume of methanol (see Note 5 and Note 6)orabsolute alcohol.NOTE 5It has been found that 99 %

31、 2-propanol (isopropyl alcohol)can be substituted for the purified ethanol with entirely satisfactory results.This substitution is not permissible, however, in referee tests.NOTE 6This composition is available under the name of “U.S.Department of Treasury Specially Denatured Formula 30 (Regulation N

32、o.3-1938).”5Formula 3A plus 5 % methanol is an equivalent.7.4 Aqueous Hydrochloric Acid Standard Solution(0.5 M)Standardize to detect molarity changes of 0.0005 bytitrating with standard alcoholic KOH solution (see 7.8 andNote 7).NOTE 7Where saponification numbers below one are expected, betterpreci

33、sion can be obtained by substituting 0.1 M KOH solution and HCl forthe 0.5 M reagents in Sections 7, 8, 10, 17, and 19.7.5 Butanone (Methyl Ethyl Ketone), technical grade. Storein dark or brown bottles. (WarningSee 4.1.)7.6 Naphtha, (WarningExtremely flammable. Harmful ifinhaled. Vapors can cause fl

34、ash fire.) ASTM PrecipitationGrade (or Petroleum Spirit-60/80 or hexanes) (WarningCombustible. Vapor harmful.) Petroleum spirit shall conformto the current IP 136.7.7 Phenolphthalein Solution, NeutralizedDissolve 1.0 g6 0.1 g of phenolphthalein in 100 mL of alcohol (see 7.3).Neutralize to faint pink

35、 color with dilute (0.1 M) alcoholicKOH solution.7.8 Alcoholic Potassium Hydroxide Standard Solution (0.5M)Prepare approximately 0.5 M solution by dissolving KOHin the alcohol specified in 7.3. Allow the solution to settle in adark place. Filter the solution, and allow to stand for 24 hbefore using.

36、4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacope

37、iaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5Available from the U.S. Bureau of Alcohol, Tobacco, and Firearms, DistilledSpirits and Tobacco Branch, 1200 Pennsylvania Avenue, NW, Washington, DC20226.D94 07 (2017)27.8.1 Alternatively, prepare 0.5 M or 0.1 M alcoh

38、olic KOHby mixing a commercially available KOH ampule (which iscarbonate free) with 95 % alcohol. Using this type solutiongives consistent blanks and does not give multiple breaks (seeNote 8).NOTE 8Because of the relatively large coefficient of cubic expansionof organic liquids such as 2-propanol (i

39、sopropyl alcohol), the standardalcoholic solution has to be standardized at temperatures close to thoseemployed in the titrations of samples.7.8.2 The KOH solutions shall be standardized by titratingwith standard potassium hydrogen phthalate solution (see 7.9and Note 8).7.9 Potassium Hydrogen Phthal

40、ate(C8H5KO4) 0.1 MStandard Solution Weigh 2.0422 g 6 0.0002 g of potassiumhydrogen phthalate that has been dried at 110 C 6 5Ctoaconstant weight into a 100 mL volumetric flask. Dissolve inreagent water. Some heating may be necessary to dissolve thesolid. Dilute to 100 mL with distilled or deionized

41、water, afterthe solution has cooled.7.10 Stoddard Solvent, technical grade. (WarningExtremely flammable. Harmful if inhaled.)7.11 Xylene, reagent grade. (WarningExtremely flam-mable. Harmful if inhaled.)8. Blank Determinations8.1 Perform a blank determination concurrently with eachset (see Note 9) (

42、one or more) of samples as follows: measureaccurately from a buret or volumetric pipet (see Note 10) intothe Erlenmeyer flask 25 mL 6 0.03 mL of alcoholic KOHsolution and 25 mL 6 1 mL of butanone (methylethyl-ketone)or one of the alternative solvents. Connect the condenser to theflask, and heat for

43、the same amount of time as that used for thesample after refluxing begins. (WarningThe reflux con-denser should be clamped securely to prevent it from tippingover onto the hot plate with possible breakage of glassware.See also Note 11. ) Immediately add 50 mL of ASTM precipi-tation naphtha (WarningS

44、ee 7.6, also Note 12 and Note 13)by cautiously pouring the naphtha down the condenser (dis-connect condenser if mushroom-type is used), and titrate theblank while hot, without reheating, with 0.5 M hydrochloricacid (HCl) using three drops of neutralized phenolphthaleinindicator solution.NOTE 9Run bl

45、ank determinations in duplicate on samples requiringthe highest accuracy. The precision data are based on duplicate blankdeterminations. A single blank is sufficient for routine work.NOTE 10If a volumetric pipet is used to measure the alcoholic KOHsolution, wait 30 s after delivery to allow for comp

46、lete drainage.NOTE 11Although standard procedure requires 30 min of reflux, somefats are readily saponified and complete saponification takes place within10 min. On the other hand, difficult saponifiable materials require morethan 2 h. Neither the shortened period nor the longer period should be use

47、dexcept by mutual consent of the interested parties.NOTE 12Pouring 50 mL of naphtha down the condenser at the end ofthe saponification not only rinses the condenser but also cools the reactionmixture.NOTE 13In the case of insulating oils, the addition of ASTMprecipitation naphtha or petroleum spirit

48、 is not necessary.8.2 After the indicator color has been discharged, add,dropwise, more indicator solution. If this addition of indicatorrestores the color, continue the titration, making further drop-wise additions of indicator, if necessary, until the end point isreached (Note 14). The end point i

49、s reached when the indicatorcolor is completely discharged and does not immediatelyreappear upon further dropwise addition of the indicatorsolution. Record as V1in 11.1.NOTE 14Avoid emulsification of titration mixture, but ensure phasecontact by swirling the flask vigorously as the end point is approached.9. Sample9.1 Using Practice D4057 (manual sampling) or PracticeD4177 (automatic sampling) as a guideline for obtaining arepresentative sample, make sure that the portion of the sampleto be tested appears homogenous. Choose