ASTM D128-98(2019)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D128 − 98 (Reapproved 2019)
Standard Test Methods for
Analysis of Lubricating Grease
This standard is issued under the fixed designation D128; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) 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. Scope Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 These test methods for analysis cover greases of the
Barriers to Trade (TBT) Committee.
conventional type, which consist essentially of petroleum oil
and soap. The constituents that can be determined are soap,
2. Referenced Documents
unsaponifiable matter (petroleum oil, and so forth), water, free
alkalinity, free fatty acid, fat, glycerin, and insolubles.
2.1 ASTM Standards:
D95 Test Method for Water in Petroleum Products and
NOTE 1—Any of the test methods described herein are best used by an
Bituminous Materials by Distillation
experienced grease analyst who may also be able to make appropriate
adaptations of the techniques as occasion requires. D156 Test Method for Saybolt Color of Petroleum Products
(Saybolt Chromometer Method)
1.2 A supplementary test method is provided in Appendix
D217 Test Methods for Cone Penetration of Lubricating
X1. This test method is intended primarily for application to
Grease
greases containing thickeners that are essentially insoluble in
D445 Test Method for Kinematic Viscosity of Transparent
n-hexane, and to greases that cannot be analyzed by conven-
and Opaque Liquids (and Calculation of Dynamic Viscos-
tional methods because of the presence of such constituents as
ity)
nonpetroleum fluids or nonsoap-type thickeners, or both. In
D473 Test Method for Sediment in Crude Oils and Fuel Oils
some cases, these constituents can react with strong acid or
by the Extraction Method
alkaline solutions.
D804 Terminology Relating to Pine Chemicals, Including
1.3 These test methods appear in the following order:
Tall Oil and Related Products
Sections
D1078 Test Method for Distillation Range of Volatile Or-
Ash Determination 7–11
ganic Liquids
Insolubles, Soap, Fat, Petroleum Oil, 12–20
and Unsaponifiable Matter D1193 Specification for Reagent Water
Free Alkali and Free Acid 21–23
D1353 Test Method for Nonvolatile Matter in Volatile Sol-
Water 24
vents for Use in Paint, Varnish, Lacquer, and Related
Glycerin (Quantitative) 25–29
Products
1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
3. Terminology
standard.
3.1 Definitions:
1.5 This standard does not purport to address all of the
3.1.1 asphalt, n—a dark brown-to-black cementitious mate-
safety concerns, if any, associated with its use. It is the
rial in which the predominating constituents are bitumens.
responsibility of the user of this standard to establish appro-
3.1.1.1 Discussion—Asphalt can be a natural product or a
priate safety, health, and environmental practices and deter-
material obtained from petroleum processing.
mine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accor-
3.1.2 candle pitch, n—a dark brown-to-black, tarry or solid,
dance with internationally recognized principles on standard-
by-product residue from soap and candle stock manufacture,
ization established in the Decision on Principles for the
refiningofvegetableoils,refiningofwoolgrease,orrefiningof
refuse animal fats.
These test methods are under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and are the direct responsibility
of Subcommittee D02.G0.01 on Chemical and General Laboratory Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 1, 2019. Published August 2019. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ɛ1
approved in 1922. Last previous edition approved in 2014 as D128 – 98 (2014) . Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D0128-98R19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D128 − 98 (2019)
3.1.3 cup grease, n—any lubricating grease having physical 3.1.11 neutralization number, n—of petroleum oil, the quan-
properties, such as consistency and texture, suitable for its use tity of acid or base required to titrate to neutrality and
in spring-loaded or screw-type lubricating cups. expressed as equivalent milligrams of potassium hydroxide per
3.1.3.1 Discussion—Cup greases are predominantly NLGI gram of sample. D804
No. 3 or 4 calcium greases, but grease types other than calcium
3.1.12 NLGI, n—National Lubricating Grease Institute.
are also used.
3.1.13 NLGI number, n—a numerical scale for classifying
3.1.4 degras(woolfat,woolgrease,woolwax),n—afat-like
the consistency range of lubricating greases and based on the
material comprised primarily of sterols, other higher alcohols,
Test Methods D217 worked penetration.
and fatty acids, obtained from the solvent extraction of sheep’s
NLGI Lubricating Grease Guide
wool.
3.1.14 non-soap thickener (synthetic thickener, inorganic
3.1.5 free alkali, n— in lubricating grease, unreacted basic
thickener, organic thickener), n—in lubricating grease, any of
(alkaline) material present in the product.
several specially treated or synthetic materials, excepting
3.1.5.1 Discussion—Many greases are made with a slight
metallicsoaps,thatcanbethermallyormechanicallydispersed
excess of alkali to ensure complete saponification. Free alkali
in liquid lubricants to form the lubricating grease structure.
is determined by acidification of a solvent-thinned specimen
NLGI Lubricating Grease Guide
and back titration with standardized, alcoholic potassium
hydroxide. It is expressed in terms of the predominating alkali 3.1.15 residuum, n—a liquid or semi-liquid product ob-
and a mass % of the total grease composition (for example,
tained as residue from the distillation of petroleum and
mass % lithium hydroxide). consisting primarily of asphaltic hydrocarbons.
3.1.15.1 Discussion—Also known as asphaltic oil, asphal-
3.1.6 free fatty acid, n—in lubricating grease, unreacted
tum oil, liquid asphalt, black oil, petroleum tailings, and
carboxylic acid(s) present in the product.
residual oil.
3.1.6.1 Discussion—Some greases are made with a slight
excess of carboxylic acid to ensure a non-alkaline product.
3.1.16 rosin oil, n—a viscous, oily liquid obtained as a
Free fatty acid is determined by neutralization of a solvent-
condensate when the residue (rosin) from turpentine produc-
thinned specimen with standardized, alcoholic potassium hy-
tion is subjected to dry, destructive distillation.
droxide.Regardlessoftheactualcompositionofthecarboxylic
3.1.16.1 Discussion—Also used to describe specially com-
acid(s), it is expressed as free oleic acid and as a mass % of the
pounded oils having a rosin base.
total grease composition.
3.1.17 saponification, n—the interaction of fats, fatty acids,
3.1.7 insolubles, n—in lubricating greases analysis, the
or esters generally with an alkali to form the metallic salt,
material remaining after the acid hydrolysis, water extraction,
which is commonly called soap.
and solvent extraction of soap-thickened greases.
3.1.17.1 Discussion—Soap thickeners are most often made
3.1.7.1 Discussion—Consisting of such products as
by in situ saponification in the lubricating grease base oil.
graphite, molybdenum disulfide, insoluble polymers, and so
However, the use of pre-formed soaps is also common;
forth.
dispersion is effected by mechanical means and usually with
3.1.8 lubricating grease, n—a semi-fluid to solid product of
heat. NLGI Lubricating Grease Guide
a dispersion of a thickener in a liquid lubricant.
3.1.18 single base, adj— in lubricating grease, relating to a
3.1.8.1 Discussion—The qualifying term, lubricating,
thickener comprised of soaps of only one metal.
should always be used. The term, grease, used without the
qualifier refers to a different product, namely certain natural or
3.1.19 soap, n—in lubricating grease, a product formed in
processed animal fats, such as tallow, lard, and so forth.
the saponification (neutralization) of fats, fatty acids, or esters
3.1.9 mixed base, adj—in lubricating grease, the description by inorganic bases.
of a thickener system composed of soaps of two metals.
3.1.20 Soxhlet apparatus, n—a device, usually of glass,
3.1.9.1 Discussion—Although mixed-base grease can be
used to extract soluble material from a mixture of soluble and
made with soaps of more than two metals, in practice, such is
insoluble (generally solid) materials, by passing a volatile
rarely, if ever, encountered. All of the soaps need not be
solvent through the sample and recirculating the solvent by
thickeners, although the major soap constituent will be one
refluxing.
capable of forming a lubricating grease structure. Because the
3.1.21 tar, n—a brown or black, bituminous, liquid or
mixed soaps are seldom present in equal amounts. The pre-
semi-solid comprised primarily of bitumens condensed in the
dominant soap is referred to first.
processingofcoal,petroleum,oil-shale,wood,orotherorganic
NLGI Lubricating Grease Guide
materials.
3.1.10 montan wax, n—a wax-like material comprised pri-
3.1.22 thickener, n—in lubricating grease, a substance com-
marily of montanic acid and its ester, higher aliphatic alcohols,
posed of finely divided solid particles dispersed in a liquid
and resins obtained from the solvent extraction of lignite.
lubricant to form the product’s structure.
3.1.22.1 Discussion—The thickener can be fibers (such as
various metallic soaps) or plates or spheres (such as certain
Available from National Lubricating Grease Institute, 4635 Wyandotte St.,
Kansas City, MO 64112-1596; http://www.nlgi.org. non-soapthickeners),whichareinsolubleor,atmost,onlyvery
D128 − 98 (2019)
TABLE 1 Physical Requirements of n-hexane
slightly soluble in the liquid lubricant. The general require-
ments are that the solid particles be extremely small, uniformly Test Requirement ASTM
A
Designation
dispersed, and capable of forming a relatively stable, gel-like
Initial boiling point, min, °C 66.1 D1078
structure with the liquid lubricant. D217
Dry point, max, °C 68.9 D1078
3.1.23 thimble, n—in Soxhlet apparatus, a closed-end po- Nonvolatile matter, max, g/100 mL 0.001 D1353
Color, Saybolt, min + 30 D156
rous cylinder used to hold the material to be extracted, usually
A
Reaction with alkalies .
made of thick matted filter paper but sometimes made of
A
Boil 125 mL of n-hexane with 10 mL of 0.5 N alcoholic KOH solution and 50 mL
ceramic.
of neutral 50 % alcohol for 1 ⁄2 h on a hot plate. Use a glass tube about 7 mm in
inside diameter and 750 mm in length as a reflux condenser. After cooling, titrate
3.1.24 total fluid constituent, n—in lubricating grease
the solutions with 0.5 N HCl using phenolphthalein as the indicator. Not less than
analysis, the n-hexane-soluble material extracted from the
9.8 mL of 0.5 N HCl shall be required for neutralization. The amount of alkali
lubricating grease sample. consumed in this test shall be deducted as a blank correction in the fat
determination on Solution E.
3.1.24.1 Discussion—Typical materials include petroleum
oil, non-petroleum fluid, soluble fats, and soluble additives.
3.1.25 total n-hexane-insoluble material, n—in lubricating
grease analysis, that portion of grease (excluding free alkali)
5.2 Purity of Water—Unless otherwise indicated, references
that is essentially insoluble in n-hexane.
towatershallbeunderstoodtomeanreagentwaterconforming
3.1.25.1 Discussion—Typical materials include thickeners,
to Specification D1193, Type III.
fillers, inorganic salts, asphaltenes, or any combinations of
5.3 Acetone—American Chemical Society Reagent Grade
these(alsoincludesinsolublematerialsfoundintheanalysisof
Acetone.(Warning—Extremelyflammable.Vaporsmaycause
contaminated grease). Free alkali content is generally insignifi-
flash fires.)
cant.
5.4 Alcohol (50 %)—The alcohol shall be prepared from
3.1.26 unsaponifiable matter, n—in lubricating grease, or-
8,9
commercial 95 % ethanol or denatured alcohol (Warning—
ganic materials, either added or found with fatty materials,
Flammable.Denatured.Cannotbemadenontoxic)bydistilling
which do not react during saponification.
fromNaOHandneutralizingexactlywithNaOHorKOHusing
phenolphthalein as the indicator. (Warning—In addition to
4. Significance and Use
other precautions, avoid skin contact or ingestion.) Dilute with
4.1 These test methods can be used to identify and estimate
an equal volume of water.
the amount of some of the constituents of lubricating greases.
5.5 Ammonium Carbonate—(NH ) CO.(Warning—
4 2 3
These test methods are applicable to many, but not all, greases.
Harmful if swallowed.) (Warning—Harmful if swallowed.)
4.2 Composition should not be considered as having any
5.6 Butter Yellow Indicator (0.02 g⁄mL)—Toluene solution
direct bearing on service performance unless such correlation
(Warning—Flammable. Vapor harmful) of
is established.
p-dimethylaminoazobenzene. (Warning—Suspected carcino-
NOTE 2—Details on other test methods for grease analysis can be found
gen. In addition to other precautions, avoid inhalation or skin
4,5,6
in other reference material.
contact.)
5.7 t-Butyl Alcohol, melting point 24 °C to 25.5 °C
5. Reagents
(Warning—Flammable liquid; causes eye burns).
5.1 Purity of Reagents—Reagent grade chemicals shall be
5.8 Carbon Disulfide (CS ). (Warning—Extremely flam-
used in all tests. Unless otherwise indicated, it is intended that
mable. Poison. Vapor may cause flash fire. Vapor harmful.
all reagents shall conform to the specifications of the Commit-
Capable of self-ignition at 100 °C or above. Harmful or fatal if
tee onAnalytical Reagents of theAmerican Chemical Society,
swallowed. May be absorbed through the skin.)
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
5.9 EthylEther.(Warning—Extremelyflammable.Harmful
sufficiently high purity to permit its use without lessening the
if inhaled. May cause eye injury. Effects may be delayed. May
accuracy of the determination.
form explosive peroxides. Vapors may cause flash fire. Mod-
erately toxic. Irritating to skin.)
9,10
5.10 n-hexane, high-purity grade, conforming to the
Stanton, G. M., “Examination of Grease by Infrared Spectroscopy,” NLGI
requirements of Table 1.(Warning—Extremely flammable.
Spokesman, Vol 38, No. 5, August 1974, pp. 153–165.
Stanton, G. M., “Grease Analysis, a Modern Multitechnique Approach,”
Preprint NLGI Annual Meeting, Oct 26–29, 1975.
6 8
Bonomo, F. S., and Schmidt, J. J. E., “Development of Schematic Analytical The sole source of supply of denatured grain alcohol known to the committee
Procedures for Synthetic Lubricants and TheirAdditives,” WADC Technical Report at this time is Formulas 1, 23-A, 30, and 35-A, as described in Publication No. 368,
54-464, Part IV, July 1957 (U.S. Government No. AD-130922). “Formulas for DenaturedAlcohol,” U.S. Treasury Dept., Internal Revenue Service.
7 9
Reagent Chemicals, American Chemical Society Specifications, American If you are aware of alternative suppliers, please provide this information to
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not ASTM International Headquarters. Your comments will receive careful consider-
listed by the American Chemical Society, see Annual Standards for Laboratory ation at a meeting of the responsible technical committee, which you may attend.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia The sole source of supply of n-hexane, high-purity grade, known to the
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, committee at this time is Phillips Petroleum Co., Special Products Div., Bartlesville,
MD. OK.
D128 − 98 (2019)
Harmful if inhaled. May produce nerve cell damage. Vapors leumoil,andunsaponifiablematter)shallbefromabout8to30
may cause flash fire.) g, depending on the consistency of the grease, which is chiefly
determined by the percentage of soap present. A 10 to 20-g
5.11 Hydrochloric Acid (37 %) —Concentrated acid (HCl).
sample is usually a convenient amount for No. 3 cup grease,
(Warning—Poison. Corrosive. May be fatal if swallowed.
while softer greases require a larger sample. The original
Liquid and vapor cause severe burns. Harmful if inhaled.)
sample shall be stirred or mixed until uniform.
5.12 Hydrochloric Acid, Standard Solution (0.5 N)—
6.2 Samplesneednotbeweighedmorecloselythanto0.1 g.
Prepare and standardize a 0.5 N solution of HCl.
5.13 Hydrochloric Acid (10 %), a solution containing 10 %
ASH DETERMINATION
by weight of concentrated HCl in water, with a permissible
7. General
variation of 0.5 %.
7.1 The percentage of ash shall not be included in the total
5.14 Hydrochloric Acid(1+3) —Mix one volume of con-
of the analysis.
centrated HCl (37 %) with three volumes of water.
NOTE 3—The determination of the total ash should not in general be
5.15 Methyl Red Indicator Solution. (Warning—
regarded as of any great importance. It is, however, sometimes required.
Flammable. Avoid skin contact or ingestion.)
This determination is often unsatisfactory because of interaction between
Na CO derived from the soap and inorganic insolubles. There is always
5.16 Nitric Acid(1+4) —Mix one volume of concentrated 2 3
likelihood of reaction with the porcelain crucible itself on account of the
nitric acid (70 %) (Warning—Poison. Corrosive. Strong oxi-
longcontinuedheatingnecessarytoburnoffallcarbon.Moreover,ifmuch
dizer. Contact with organic material may cause fire. May be
Na CO or K CO is present, the ash is fusible and often encloses carbon,
2 3 2 3
harmful if swallowed. Liquid and vapor cause severe burns)
making complete removal of the latter very difficult. Results will always
with four volumes of water. be low in the presence of easily reducible oxides of volatile metals. There
is also uncertainty as to when CaCO has been completely ignited to CaO.
5.17 Phenolphthalein Indicator Solution—The phenol-
Ash determinations made on the same sample in different laboratories are
phthalein solution shall be prepared by dissolving 1.0 g phe-
likely to vary widely.
nolphthalein (Warning—In addition to other precautions,
8. Rapid Routine Test Method
avoidskincontactoringestion)in50 mLofalcoholdistilledas
8.1 Place a 2 g to 5 g sample of the grease in a weighed
described in 5.4, adding 5 mL of water and neutralizing with
porcelain crucible and weigh the sample to the nearest 0.1 g. If
NaOH or KOH.
lead or zinc soap is known to be absent, a platinum crucible is
5.18 Potassium Hydrogen Sulfate (KHSO ). (Warning—
more convenient. Slowly burn off the combustible matter, and
Poison. Harmful or fatal if swallowed. Causes severe eye and
finally ignite the residue until the ash is free of carbonaceous
skin irritation or injury. Dust or mist may be harmful.)
matter. Cool the crucible and contents in a desiccator and
5.19 Potassium Hydroxide (KOH), Alcoholic (0.5 N)—
weigh, reporting the result as percentage of ash.
Prepareandstandardizea0.5 Nsolutionofalcoholicpotassium
9. Alternative Test Method
hydroxide. (Warning—Poison. Causes eye and skin damage.)
9.1 Burn the sample in accordance with 8.1 until the ash is
5.20 Potassium Periodate (KIO ). (Warning—May be irri-
nearly free from carbon. Cool the crucible and contents,
tating to skin and eyes. May react vigorously with reducing
dissolve the soluble portions in a little water, and add a slight
agents.)
excess of H SO (1 + 4), (Warning—Poison. Corrosive.
2 4
5.21 Sodium Carbonate—(Na CO ). (Warning—Harmful
2 3
Strong oxidizer. Contact with organic material may cause fire.
if swallowed. May cause skin irritation.)
May be fatal if swallowed. Liquid and vapor cause severe
5.22 Sodium Hydroxide (240 g⁄L)—Dissolve 240 g of so-
burns. Harmful if inhaled. Contact with water liberates large
dium hydroxide (NaOH) (Warning—Poison. Causes eye and
amounts of heat) running the acid in carefully from a pipet
skin damage) in water and dilute to 1 L.
inserted under a small watch glass covering the crucible.Warm
the crucible and contents on a steam bath until effervescence
5.23 Sodium Hydroxide Solution, Standard (0.05 N)—
has ceased. Rinse the watch glass with water into the crucible.
Prepare and standardize a 0.05 N NaOH solution.
The solution, when tested with methyl red (Warning—
5.24 Sulfuric Acid (1+4) —Carefully mix one volume of
Flammable. Avoid skin contact or ingestion) for free acidity,
concentrated sulfuric acid (H SO 95 %) with four volumes of
2 4
shall show free acid present. Evaporate the contents of the
water. (Warning—Poison. Corrosive. Strong oxidizer. Contact
crucible to dryness and ignite the whole at a low red heat,
with organic material may cause fire. May be fatal if swal-
adding a few small pieces of dry (NH ) CO (Warning—
4 2 3
lowed. Liquid and vapor cause severe burns. Harmful if
Harmful if swallowed) to drive off the excess SO . After
inhaled. Contact with water liberates large amounts of heat.)
cooling and weighing, report the result as percentage of ash as
5.25 Sulfuric Acid (3 + 20) —Carefully mix 3 mL of con-
sulfates.
centrated sulfuric acid (95 %) with 20 mL of water.
NOTE 4—This test method gives more concordant results than the
5.26 Toluene. (Warning— Flammable. Vapor harmful.)
routine method (Section 8), but it requires more time and manipulation.
6. Sample 10. Qualitative Examination
6.1 The sample size for the soap determination (Test Meth- 10.1 Aneasilyfusibleash,dissolvingcompletelyinwaterto
ods I and II for determination of insolubles, soap, fat, petro- give a strongly alkaline solution, indicates a grease containing
D128 − 98 (2019)
FIG. 1 Scheme of Grease Analysis
sodium, potassium, or both. Lithium is indicated by a white 11. Quantitative Examination
infusible ash, readily soluble in water, giving a strongly
11.1 For the quantitative examination of ash, use any
alkaline solution.Awhite infusible ash, practically insoluble in
standard analytical procedure, basing the choice of methods on
water but imparting to it an alkaline reaction, may indicate
the information gained from the qualitative tests. If only one
calcium, with or without magnesium or aluminum. Zinc is
base is present, a quantitative determination is, in general,
shown by the yellow color of the ash while hot, and lead may
unnecessary.
be indicated by the presence of metallic globules or by the
yellow color of the ash when cold. INSOLUBLES, SOAP, FAT, PETROLEUM OIL, AND
UNSAPONIFIABLE MATTER
10.2 Dissolve the ash in HNO (1+4)(Warning—Poison.
Corrosive. Strong oxidizer. Contact with organic material may
12. Choice of Test Method
cause fire. May be harmful if swallowed. Liquid and vapor
cause severe burns) or HCl (1 + 3) (Warning—Poison. Cor- 12.1 Examine greases containing residuum, asphaltic oils
rosive. May be fatal if swallowed. Liquid and vapor cause and asphalt, tars, and so forth, using Test Method II, as these
severe burns. Harmful if inhaled.) Confirm the presence of the ingredients usually cause stubborn emulsions if a vigorous
several bases by suitable chemical tests, following any stan- agitation process is applied at the start. Analyze all other
dard scheme of qualitative analysis. greases using Test Method I. (See Fig. 1.)
D128 − 98 (2019)
Test Method I 10 min to 15 min are usually sufficient. Disregard any inor-
ganicsaltsthatmayprecipitate.Coolthecontentsofthebeaker
13. Insolubles to room temperature.
13.1 Ifinsolublesarepresent(seeNote5),weighthesample
14.4 Transfer the contents of the flask or beaker to a
(seesection6)inasmallbeaker,add50 mLofHCl(10 %),and
separatory funnel, using n-hexane and water as washing
warm the beaker on a steam bath, stirring until all soap lumps
liquids. Allow this solution (or the combined filtrate and
have disappeared and the upper layer is clear. If undissolved
washings, except the alcohol washings, from the determination
mineral matter or other insoluble is present, filter both layers
of insolubles, Section 13, transferred to a separator), to clear
while warm through a Gooch crucible provided with a suitable
and draw the aqueous layer, A, which contains all the bases as
mat, wash the beaker and crucible with warm (60 °C to 63 °C)
well as glycerin, into another separator. Wash the n-hexane
water (see Note 6) and n-hexane, (Warning—Extremely
layer, B, three times with 25 mL portions of water to remove
flammable. Harmful if inhaled. May produce nerve cell dam-
HCl, adding the washings to A. Wash the aqueous solution, A,
age. Vapors may cause flash fire.) Finally, wash the crucible
twice with 20 mL portions of n-hexane, C, and then set
with alcohol (Warning—Flammable. Denatured. Cannot be
Solution A aside for examination for glycerin (Section 16).
made nontoxic.) collecting the alcohol washings separately,
WashSolution Concewith15 mLofwater,whichmaythenbe
and discarding them. Dry the crucible and contents at 120 °C
discarded, and add C to B. If Solutions B and C are compara-
and weigh, reporting the result as percentage of insoluble
tively light-colored, an approximate determination of free fatty
matter (graphite, molybdenum disulfide, and so forth).
acids and fatty acids from soap can now be made by titrating
NOTE 5—If no insolubles are present, omit the procedure given in the solution in the separator with 0.5 N alcoholic KOH
Section 13.
solution (Warning—Poison. Causes eye and skin damage)
NOTE 6—Throughout the test method where the word warm is used, it
using phenolphthalein (Warning—In addition to other
is to be understood that a temperature of 60 °C to 63 °C is to be used.
precautions, avoid skin contact or ingestion) as the indicator,
and using 200 as the average neutralization value of the fatty
14. Soap
acid (that is, 1.0 g of fatty acid requires 200 mg of absolute
14.1 If insolubles are absent, decompose a sample of the
KOH for neutralization). If Solutions B and C are dark, add a
grease, either by the two-phase procedure as described in 14.2
few drops of phenolphthalein solution and sufficient 0.5 N
or by the single-phase procedure as described in 14.3. In either
alcoholic KOH solution to make the alcoholic layer distinctly
case, if the contents of the flask or beaker remain liquid, follow
alkaline after vigorous shaking.
the procedure described in 14.4. If contents congeal, or if, in
NOTE 7—Capital letters reference solutions given in Fig. 1.
the case of the two-phase decomposition, solid particles form,
follow the procedure described in 14.5.
14.5 Heat the contents of the flask or beaker to approxi-
mately 63 °C and transfer to a separ
...