ASTM D820-93(2016)
(Test Method)Standard Test Methods for Chemical Analysis of Soaps Containing Synthetic Detergents
Standard Test Methods for Chemical Analysis of Soaps Containing Synthetic Detergents
ABSTRACT
These test methods detail the standard procedures for the chemical analysis of soaps containing synthetic detergents. The analytical procedures include the determination of the following chemical properties and substances: moisture and other matter volatile at a specified temperature; free alkali or free acid; anhydrous, salt-free soda soap; alcohol-soluble matter; matter insoluble in water; total alkalinity of matter insoluble in alcohol (alkaline salts); sodium silicate; phosphates; phosphates by colorimetric method using molybdenum blue); unsaponified and unsaponifiable matter; free fatty matter; chlorides in alcohol-soluble matter; rosin by McNicoll method; synthetic detergent by difference; and neutral inorganic salts.
SCOPE
1.1 These test methods cover procedures for the chemical analysis of soaps containing synthetic detergents.
1.2 The analytical procedures appear in the following order:
Sections
Moisture and Other Matter Volatile at 105°C (Oven Method)
5 and 6
Free Alkali or Free Acid
7 and 8
Anhydrous, Salt-Free, Soda Soap
9 – 12
Alcohol-Soluble Matter
13 and 14
Matter Insoluble in Water
15 and 15
Total Alkalinity of Matter Insoluble in Alcohol (Alkaline Salts)
16 and 17
Sodium Silicate
18 – 20
Phosphates
21 – 28
Phosphate (Colorimetric Method Using Molybdenum Blue)
29 – 34
Unsaponified and Unsaponifiable Matter
35 – 39
Free Fatty Matter
40
Chlorides in Alcohol-Soluble Matter
41 – 43
Rosin (McNicoll Method)
44 – 47
Synthetic Detergent (by Difference)
48
Neutral, Inorganic Salts
49
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D820 − 93 (Reapproved 2016)
Standard Test Methods for
Chemical Analysis of Soaps Containing Synthetic
Detergents
This standard is issued under the fixed designation D820; 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.
1. Scope D216 Method of Test for Distillation of Natural Gasoline
(Withdrawn 1988)
1.1 These test methods cover procedures for the chemical
D459 Terminology Relating to Soaps and Other Detergents
analysis of soaps containing synthetic detergents.
D875 Method for Calculating of Olefins and Aromatics in
1.2 The analytical procedures appear in the following order:
Petroleum Distillates from Bromine Number and Acid
Absorption (Withdrawn 1984)
Sections
D1193 Specification for Reagent Water
Moisture and Other Matter Volatile at 105°C (Oven Method) 5 and 6
D1768 Test Method for Sodium Alkylbenzene Sulfonate in
Free Alkali or Free Acid 7 and 8
Synthetic Detergents by Ultraviolet Absorption
Anhydrous, Salt-Free, Soda Soap 9 – 12
Alcohol-Soluble Matter 13 and 14
D2357 for Qualitative Classification of Surfactants by Infra-
Matter Insoluble in Water 15 and 15
red Absorption
Total Alkalinity of Matter Insoluble in Alcohol (Alkaline Salts) 16 and 17
Sodium Silicate 18 – 20 D2358 Test Method for Separation of Active Ingredient from
Phosphates 21 – 28
Surfactant and Syndet Compositions
Phosphate (Colorimetric Method Using Molybdenum Blue) 29 – 34
D3049 Test Method for Synthetic Anionic Ingredient by
Unsaponified and Unsaponifiable Matter 35 – 39
Free Fatty Matter 40 Cationic Titration
Chlorides in Alcohol-Soluble Matter 41 – 43
Rosin (McNicoll Method) 44 – 47
3. Terminology
Synthetic Detergent (by Difference) 48
Neutral, Inorganic Salts 49
3.1 Definitions:
1.3 The values stated in SI units are to be regarded as
3.2 The term synthetic detergent in these test methods is
standard. No other units of measurement are included in this
defined in accordance with Terminology D459, as follows:
standard.
3.3 synthetic detergent—a detergent produced by chemical
1.4 This standard does not purport to address all of the
synthesis and comprising an organic composition other than
safety problems, if any, associated with its use. It is the
soap.
responsibility of the user of this standard to establish appro-
3.4 For definitions of other terms used in these test methods,
priate safety and health practices and determine the applica-
refer to Terminology D459.
bility of regulatory limitations prior to use.
4. Purity of Reagents and Materials
2. Referenced Documents
4.1 Purity of Reagents—Reagent grade chemicals shall be
2.1 ASTM Standards:
used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society,
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
These test methods are under the jurisdiction of ASTM Committee D12 on
Soaps and Other Detergentsand are the direct responsibility of Subcommittee
D12.12 on Analysis and Specifications of Soaps, Synthetics, Detergents and their
Components. The last approved version of this historical standard is referenced on
Current edition approved July 1, 2016. Published August 2016. Originally www.astm.org.
approved in 1945. Last previous edition approved in 2009 as D820 – 93(2009). Reagent Chemicals, American Chemical Society Specifications, American
DOI: 10.1520/D0820-93R16. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D820 − 93 (2016)
sufficiently high purity to permit its use without lessening the 9.2 Stokes Flask, 100-mL, round-bottom (with the bottom
accuracy of the determination. blown out), sealed onto a 150-mL Erlenmeyer flask. A diagram
of the Stokes flask is shown in Fig. 1.
4.2 Unless otherwise indicated, references to water shall be
understood to mean reagent water conforming to Specification 9.3 Siphon, consisting of a two-hole rubber stopper fitted
D1193. with small-diameter glass tubing as shown in Fig. 2.
MOISTURE AND OTHER MATTER VOLATILE AT
10. Reagents
105°C (OVEN METHOD)
10.1 Ethyl Alcohol, Neutral (95 %) —Freshly boiled, re-
agent grade, ethyl alcohol, 95 % or higher, neutral to
5. Apparatus
phenolphthalein, and containing only volatile denaturants, 95
5.1 Dish—A porcelain or glass dish about 6 to 8 cm in
mL, plus 5 mL of water.
diameter and about 2 to 4 cm in depth will be required.
10.2 Methyl Orange Indicator Solution (1 g/litre)—Dissolve
0.1 g of methyl orange in water and dilute to 100 mL.
6. Procedure
10.3 Petroleum Ether—The solvent used shall be of the
6.1 Weigh 5 6 0.01 g of the sample in the dish, and dry to
pentane type, containing a minimum amount of isopentane,
constant weight in an air oven at a temperature of 105 6 2°C.
isohexane, and hexane, and boiling in the range 35 to 60°C.
Constant weight is attained when heating for successive 1-h
A
Distillation test:
periods shows a loss (or gain) of not more than 0.1 %.
Initial boiling point 35 to 38°C
Dry flask end point 52 to 60°C
NOTE 1—Because of its established use in the trade, the term weight is
Distilling under 54°C, min 95 %
employed in these methods in place of the technically correct term mass.
Distilling under 40°C, max 60 %
Specific gravity at 15.5/15.5°C (60/60°F) 0.630 to 0.660
FREE ALKALI OR FREE ACID
Color water-white
Doctor test sweet
Evaporation residue, 100 mL, max 0.0011 g
7. Reagents
B
Copper-strip corrosion test noncorrosive
C
7.1 Ethyl Alcohol, Neutral (95 %) —Freshly boiled, reagent
Unsaturated compounds trace only permitted
Residue in distilling flask neutral to methyl orange
grade, ethyl alcohol, 95 % or higher, neutral to
D
Blotter-strip odor test odorless within 12 min
phenolphthalein, and containing only volatile denaturants, 95
E
Aromatic compounds no nitrobenzene odor
mL, plus 5 mL of water.
Saponification value less than 1.0 mg KOH/100 mL
7.2 Phenolphthalein Indicator Solution (10 g/litre)—
A
The distillation test shall be made in accordance with Method D216. As a check
Dissolve 1 g of phenolphthalein in 50 mL of neutral ethyl
on the evaporation residue, 250 mL of the petroleum ether and 0.25 g of stearin or
alcohol (95 %) and mix with 50 mL of water (see 7.1). other hard fat (previously brought to constant weight by heating) when dried as in
the actual determination (10.4) shall not show an increase in weight exceeding
0.003 g.
8. Procedure B
The copper-strip corrosion test shall be made by inserting a small polished
copper strip into the petroleum ether in the distilling flask. There should be no
8.1 Weigh 5 to 10 6 0.01 g of the sample into a 300-mL
appreciable darkening of the copper.
C
Erlenmeyer flask. Add 200 mL of neutral ethyl alcohol (95 %).
Unsaturated compounds shall be determined by the method for determining
olefins described in Method D875.
Equip the flask with an air-cooled reflux condenser, and digest
the sample on a steam bath until the soap is dissolved (see Note
2). Remove the condenser, add 0.5 mL of the phenolphthalein
indicator solution, and titrate immediately with standard acid
J. T. Baker Analyzed Reagent 9268, or its equivalent, is suitable for this
or alkali. Calculate as NaOH, if alkaline, or as oleic acid, if
purpose.
acid.
NOTE 2—In the analysis of soaps known to contain little or no alkaline
salts, it is unnecessary to filter the hot alcoholic soap solution. However,
the filtration should be carried out in all cases where alkaline salts such as
silicates, phosphates, borates, and similar salts are present, since these are
known to affect the free alkali determination. Free alkali figures in soap or
surfactant mixtures containing borax are unreliable, due to solubility of
borax in hot alcohol.
ANHYDROUS, SALT-FREE, SODA SOAP
9. Apparatus
9.1 Extraction Cylinder, 250-mL, graduated, glass-
stoppered, about 39 mm (1 ⁄2 in.) in diameter and about 35.5
cm (14 in.) in length.
Fischer Scientific A962, or its equivalent, is suitable for this purpose. FIG. 1 Stokes Flask
D820 − 93 (2016)
Stokes flask. Cool the cylinder or flask under tap water to a
temperature not to exceed 25°C. Add 50 mL of petroleum ether
and allow to stand for ⁄2 h without shaking. Remove the
greater part of the fatty acids by drawing off the petroleum
ether layer as closely as possible, by means of a glass siphon,
into a 500-mL separatory funnel. Repeat the extractions five
more times with petroleum ether, using 50-mL portions, and
shaking the cylinder thoroughly each time.
NOTE 3—If an emulsion appears at this point, it may be broken by the
addition of 10 g of anhydrous Na SO .
2 4
11.3 Combine the petroleum ether extracts and wash with
small portions of distilled water until the water washings are no
longer acid to methyl orange indicator solution. Dry the
combined, washed, petroleum ether extracts with anhydrous
Na SO , and filter through paper into the original tared 250-mL
FIG. 2 Siphon
2 4
beaker. Wash the separatory funnel with two small portions of
petroleum ether, filtering and adding the washings to the
D
Odor test: Immerse 1 in. of a strip of white unglazed blotting paper, approxi-
beaker.
mately 1 by 4 by 0.166 in. in size, in the petroleum ether for 30 s, remove the strip,
and allow to dry at room temperature in still air for 12 min.
11.4 Evaporate the petroleum ether extract on the steam
E
Aromatic compounds: Add 5 drops of petroleum ether to 40 drops of sulfuric acid
(H SO , sp gr 1.84) and 10 drops of nitric acid (HNO , sp gr 1.42) in a test tube, bath until about 1 mL remains. Then swirl manually until the
2 4 3
warm for 10 min, allow to cool for 30 min, transfer to a shallow dish, and dilute with
last trace of solvent evaporates and the odor of petroleum ether
water.
is no longer perceptible. Cool in a desiccator and weigh as total
10.4 Phenolphthalein Indicator Solution (10 g/litre)—
fatty matter, which is defined as fatty and rosin acids plus
Dissolve 1 g of phenolphthalein in 50 mL of neutral ethyl
unsaponified and unsaponifiable fatty matter.
alcohol (95 %) and then mix with 50 mL of water (see 10.1).
11.5 Dissolve the total fatty matter in 50 mL of neutral ethyl
10.5 Sodium Hydroxide, Standard Solution (0.1 N)
alcohol (95 % v) with warming. Add phenolphthalein indicator
—Prepare and standardize a 0.1 N sodium hydroxide (NaOH)
and titrate with 0.1 NaOH solution to a pink end point.
solution.
12. Calculations
10.6 Sodium Sulfate (Na SO ), anhydrous.
2 4
12.1 Calculate the percentage of anhydrous, salt-free, soda
10.7 Sulfuric Acid, Standard (0.5 N)—Prepare and standard-
soap as follows:
ize a 0.5 N sulfuric acid (H SO ) solution.
2 4
A 5 G 2 F (1)
10.8 Sulfuric Acid (sp gr 1.84)—Concentrated sulfuric acid
(H SO ).
2 4
G 5 @~~VN3 0.022!1E!/W# 3 100
10.9 Sulfur Acid (1+1)—Gradually pour 10 g of concen-
where:
trated sulfuric acid (H SO ) (sp gr 1.84) onto 10 g of cracked
2 4
A = weight percent of anhydrous, salt-free, soda soap,
ice made from distilled water, gently swirling the mixing
G = weight percent of soda soap plus unsaponified and
vessel; or gradually pour the acid down the sides of the mixing
unsaponifiable fatty matter,
vessel into an equal weight of water, swirling gently, while
F = weight percent of unsaponified and unsaponifiable
submersing the vessel in an ice bath.
fatty matter (Section 39),
V = millilitres of NaOH solution used in titration (11.5),
11. Procedure
N = normality of NaOH solution,
11.1 Weigh 2 6 0.001 g of the sample into a tared 250-mL
E = grams of extract (11.4), and
beaker. Add 25 mL of water and 25 mL of neutral ethyl alcohol
W = grams of sample (11.1), and
(95 %), and warm on the steam bath until solution is complete.
0.022 = net gain in milliequivalent weight from the conver-
Cool, add 5 drops of methyl orange indicator solution, and
sion of the fatty acid to the sodium salt by replace-
titrate with 0.5 N H SO to a pink color. Add 5 mL of H SO
ment of a proton with a sodium ion.
2 4 2 4
(1+1) in excess.
ALCOHOL-SOLUBLE MATTER
11.2 Transfer the contents of the beaker to a 250-mL
extraction cylinder or a Stokes flask, equipped with a siphon.
13. Reagents
Wash the beaker alternately with equal parts of hot water and
13.1 Ethyl Alcohol, Neutral (95 %) —Freshly boiled, re-
hot ethyl alcohol (95 %), adding the washings to the extraction
agent grade, ethyl alcohol, 95 % or higher, neutral to
cylinder or Stokes flask. Keep the total volume for extraction
phenolphthalein, and containing only volatile denaturants, 95
under 160 mL in the extraction cylinder, or within the
mL plus 5 mL of water.
constricted portion of the Stokes flask. Wash the beaker with a
small amount of petroleum ether to remove any traces of fatty 13.2 Ethyl Alcohol, Neutral (absolute) —Freshly boiled
acids and fatty matter and add to the extraction cylinder or absolute ethyl alcohol, neutral to phenolphthalein.
D820 − 93 (2016)
14. Procedure Na CO , % weight5 106 VN/20 W (2)
2 3
14.1 Weigh 2 6 0.001 g of the sample into a 250-mL
where:
beaker. Add 100 mL of neutral ethyl alcohol (95 %), cover the
V = millilitres of standard acid used,
beaker, and heat on the steam bath with frequent stirring and
N = normality of standard acid, and
maceration of the sample until completely disintegrated. Let
W = weight of sample (14.1), g
settle and filter the supernatant liquid through a tared Gooch
SODIUM SILICATE
crucible with a glass wool pad, with suction into a tared
300-mL Erlenmeyer flask, retaining as much of the residue as
18. Reagents
possible in the beaker. Repeat this extraction three times with
25-mL portions of hot neutral ethyl alcohol (95 %), each time 18.1 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
chloric acid (HCl).
retaining as much of the residue as possible in the beaker.
Finally, evaporate any remaining alcohol an
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D820 − 93 (Reapproved 2009) D820 − 93 (Reapproved 2016)
Standard Test Methods for
Chemical Analysis of Soaps Containing Synthetic
Detergents
This standard is issued under the fixed designation D820; 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.
1. Scope
1.1 These test methods cover procedures for the chemical analysis of soaps containing synthetic detergents.
1.2 The analytical procedures appear in the following order:
Sections
Moisture and Other Matter Volatile at 105°C (Oven Method) 5 and 6
Free Alkali or Free Acid 7 and 8
Anhydrous, Salt-Free, Soda Soap 9 – 12
Alcohol-Soluble Matter 13 and 14
Matter Insoluble in Water 15 and 15
Total Alkalinity of Matter Insoluble in Alcohol (Alkaline Salts) 16 and 17
Sodium Silicate 18 – 20
Phosphates 21 – 28
Phosphate (Colorimetric Method Using Molybdenum Blue) 29 – 34
Unsaponified and Unsaponifiable Matter 35 – 39
Free Fatty Matter 40
Chlorides in Alcohol-Soluble Matter 41 – 43
Rosin (McNicoll Method) 44 – 47
Synthetic Detergent (by Difference) 48
Neutral, Inorganic Salts 49
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D216 Method of Test for Distillation of Natural Gasoline (Withdrawn 1988)
D459 Terminology Relating to Soaps and Other Detergents
D875 Method for Calculating of Olefins and Aromatics in Petroleum Distillates from Bromine Number and Acid Absorption
(Withdrawn 1984)
D1193 Specification for Reagent Water
D1768 Test Method for Sodium Alkylbenzene Sulfonate in Synthetic Detergents by Ultraviolet Absorption
D2357 for Qualitative Classification of Surfactants by Infrared Absorption
D2358 Test Method for Separation of Active Ingredient from Surfactant and Syndet Compositions
D3049 Test Method for Synthetic Anionic Ingredient by Cationic Titration
3. Terminology
3.1 Definitions:
3.2 The term synthetic detergent in these test methods is defined in accordance with Terminology D459, as follows:
These test methods are under the jurisdiction of ASTM Committee D12 on Soaps and Other Detergentsand are the direct responsibility of Subcommittee D12.12 on
Analysis and Specifications of Soaps, Synthetics, Detergents and their Components.
Current edition approved Oct. 1, 2009July 1, 2016. Published December 2009August 2016. Originally approved in 1945. Last previous edition approved in 20032009 as
D820 – 93(2003).(2009). DOI: 10.1520/D0820-93R09.10.1520/D0820-93R16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D820 − 93 (2016)
3.3 synthetic detergent—a detergent produced by chemical synthesis and comprising an organic composition other than soap.
3.4 For definitions of other terms used in these test methods, refer to Terminology D459.
4. Purity of Reagents and Materials
4.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
4.2 Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to Specification
D1193.
MOISTURE AND OTHER MATTER VOLATILE AT 105°C (OVEN METHOD)
5. Apparatus
5.1 Dish—A porcelain or glass dish about 6 to 8 cm in diameter and about 2 to 4 cm in depth will be required.
6. Procedure
6.1 Weigh 5 6 0.01 g of the sample in the dish, and dry to constant weight in an air oven at a temperature of 105 6 2°C.
Constant weight is attained when heating for successive 1-h periods shows a loss (or gain) of not more than 0.1 %.
NOTE 1—Because of its established use in the trade, the term weight is employed in these methods in place of the technically correct term mass.
FREE ALKALI OR FREE ACID
7. Reagents
7.1 Ethyl Alcohol, Neutral (95 %) —Freshly boiled, reagent grade, ethyl alcohol, 95 % or higher, neutral to phenolphthalein, and
containing only volatile denaturants, 95 mL, plus 5 mL of water.
7.2 Phenolphthalein Indicator Solution (10 g/litre)—Dissolve 1 g of phenolphthalein in 50 mL of neutral ethyl alcohol (95 %)
and mix with 50 mL of water (see 7.1).
8. Procedure
8.1 Weigh 5 to 10 6 0.01 g of the sample into a 300-mL Erlenmeyer flask. Add 200 mL of neutral ethyl alcohol (95 %). Equip
the flask with an air-cooled reflux condenser, and digest the sample on a steam bath until the soap is dissolved (see Note 2). Remove
the condenser, add 0.5 mL of the phenolphthalein indicator solution, and titrate immediately with standard acid or alkali. Calculate
as NaOH, if alkaline, or as oleic acid, if acid.
NOTE 2—In the analysis of soaps known to contain little or no alkaline salts, it is unnecessary to filter the hot alcoholic soap solution. However, the
filtration should be carried out in all cases where alkaline salts such as silicates, phosphates, borates, and similar salts are present, since these are known
to affect the free alkali determination. Free alkali figures in soap or surfactant mixtures containing borax are unreliable, due to solubility of borax in hot
alcohol.
ANHYDROUS, SALT-FREE, SODA SOAP
9. Apparatus
9.1 Extraction Cylinder, 250-mL, graduated, glass-stoppered, about 39 mm (1 ⁄2 in.) in diameter and about 35.5 cm (14 in.) in
length.
9.2 Stokes Flask, 100-mL, round-bottom (with the bottom blown out), sealed onto a 150-mL Erlenmeyer flask. A diagram of
the Stokes flask is shown in Fig. 1.
9.3 Siphon, consisting of a two-hole rubber stopper fitted with small-diameter glass tubing as shown in Fig. 2.
10. Reagents
10.1 Ethyl Alcohol, Neutral (95 %) —Freshly boiled, reagent grade, ethyl alcohol, 95 % or higher, neutral to phenolphthalein,
and containing only volatile denaturants, 95 mL, plus 5 mL of water.
10.2 Methyl Orange Indicator Solution (1 g/litre)—Dissolve 0.1 g of methyl orange in water and dilute to 100 mL.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
Fischer Scientific A962, or its equivalent, is suitable for this purpose.
D820 − 93 (2016)
FIG. 1 Stokes Flask
FIG. 2 Siphon
10.3 Petroleum Ether—The solvent used shall be of the pentane type, containing a minimum amount of isopentane, isohexane,
and hexane, and boiling in the range 35 to 60°C.
A
Distillation test:
Initial boiling point 35 to 38°C
Dry flask end point 52 to 60°C
Distilling under 54°C, min 95 %
Distilling under 40°C, max 60 %
Specific gravity at 15.5/15.5°C (60/60°F) 0.630 to 0.660
Color water-white
Doctor test sweet
Evaporation residue, 100 mL, max 0.0011 g
B
Copper-strip corrosion test noncorrosive
C
Unsaturated compounds trace only permitted
Residue in distilling flask neutral to methyl orange
D
Blotter-strip odor test odorless within 12 min
E
Aromatic compounds no nitrobenzene odor
Saponification value less than 1.0 mg KOH/100 mL
A
The distillation test shall be made in accordance with Method D216. As a check on the evaporation residue, 250 mL of the petroleum ether and 0.25 g of stearin or other
hard fat (previously brought to constant weight by heating) when dried as in the actual determination (10.4) shall not show an increase in weight exceeding 0.003 g.
B
The copper-strip corrosion test shall be made by inserting a small polished copper strip into the petroleum ether in the distilling flask. There should be no appreciable
darkening of the copper.
C
Unsaturated compounds shall be determined by the method for determining olefins described in Method D875.
D
Odor test: Immerse 1 in. of a strip of white unglazed blotting paper, approximately 1 by 4 by 0.166 in. in size, in the petroleum ether for 30 s, remove the strip, and allow
to dry at room temperature in still air for 12 min.
E
Aromatic compounds: Add 5 drops of petroleum ether to 40 drops of sulfuric acid (H SO , sp gr 1.84) and 10 drops of nitric acid (HNO , sp gr 1.42) in a test tube, warm
2 4 3
for 10 min, allow to cool for 30 min, transfer to a shallow dish, and dilute with water.
10.4 Phenolphthalein Indicator Solution (10 g/litre)—Dissolve 1 g of phenolphthalein in 50 mL of neutral ethyl alcohol (95 %)
and then mix with 50 mL of water (see 10.1).
J. T. Baker Analyzed Reagent 9268, or its equivalent, is suitable for this purpose.
D820 − 93 (2016)
10.5 Sodium Hydroxide, Standard Solution (0.1 N) —Prepare and standardize a 0.1 N sodium hydroxide (NaOH) solution.
10.6 Sodium Sulfate (Na SO ), anhydrous.
2 4
10.7 Sulfuric Acid, Standard (0.5 N)—Prepare and standardize a 0.5 N sulfuric acid (H SO ) solution.
2 4
10.8 Sulfuric Acid (sp gr 1.84)—Concentrated sulfuric acid (H SO ).
2 4
10.9 Sulfur Acid (1+1)—Gradually pour 10 g of concentrated sulfuric acid (H SO ) (sp gr 1.84) onto 10 g of cracked ice made
2 4
from distilled water, gently swirling the mixing vessel; or gradually pour the acid down the sides of the mixing vessel into an equal
weight of water, swirling gently, while submersing the vessel in an ice bath.
11. Procedure
11.1 Weigh 2 6 0.001 g of the sample into a tared 250-mL beaker. Add 25 mL of water and 25 mL of neutral ethyl alcohol
(95 %), and warm on the steam bath until solution is complete. Cool, add 5 drops of methyl orange indicator solution, and titrate
with 0.5 N H SO to a pink color. Add 5 mL of H SO (1+1) in excess.
2 4 2 4
11.2 Transfer the contents of the beaker to a 250-mL extraction cylinder or a Stokes flask, equipped with a siphon. Wash the
beaker alternately with equal parts of hot water and hot ethyl alcohol (95 %), adding the washings to the extraction cylinder or
Stokes flask. Keep the total volume for extraction under 160 mL in the extraction cylinder, or within the constricted portion of the
Stokes flask. Wash the beaker with a small amount of petroleum ether to remove any traces of fatty acids and fatty matter and add
to the extraction cylinder or Stokes flask. Cool the cylinder or flask under tap water to a temperature not to exceed 25°C. Add 50
mL of petroleum ether and allow to stand for ⁄2 h without shaking. Remove the greater part of the fatty acids by drawing off the
petroleum ether layer as closely as possible, by means of a glass siphon, into a 500-mL separatory funnel. Repeat the extractions
five more times with petroleum ether, using 50-mL portions, and shaking the cylinder thoroughly each time.
NOTE 3—If an emulsion appears at this point, it may be broken by the addition of 10 g of anhydrous Na SO .
2 4
11.3 Combine the petroleum ether extracts and wash with small portions of distilled water until the water washings are no longer
acid to methyl orange indicator solution. Dry the combined, washed, petroleum ether extracts with anhydrous Na SO , and filter
2 4
through paper into the original tared 250-mL beaker. Wash the separatory funnel with two small portions of petroleum ether,
filtering and adding the washings to the beaker.
11.4 Evaporate the petroleum ether extract on the steam bath until about 1 mL remains. Then swirl manually until the last trace
of solvent evaporates and the odor of petroleum ether is no longer perceptible. Cool in a desiccator and weigh as total fatty matter,
which is defined as fatty and rosin acids plus unsaponified and unsaponifiable fatty matter.
11.5 Dissolve the total fatty matter in 50 mL of neutral ethyl alcohol (95 % v) with warming. Add phenolphthalein indicator
and titrate with 0.1 NaOH solution to a pink end point.
12. Calculations
12.1 Calculate the percentage of anhydrous, salt-free, soda soap as follows:
A 5 G 2 F (1)
G 5 VN 30.022 1E /W 3100
@~~ ! ! #
where:
A = weight percent of anhydrous, salt-free, soda soap,
G = weight percent of soda soap plus unsaponified and unsaponifiable fatty matter,
F = weight percent of unsaponified and unsaponifiable fatty matter (Section 39),
V = millilitres of NaOH solution used in titration (11.5),
N = normality of NaOH solution,
E = grams of extract (11.4), and
W = grams of sample (11.1), and
0.022 = net gain in milliequivalent weight from the conversion of the fatty acid to the sodium salt by replacement of a proton
with a sodium ion.
ALCOHOL-SOLUBLE MATTER
13. Reagents
13.1 Ethyl Alcohol, Neutral (95 %) —Freshly boiled, reagent grade, ethyl alcohol, 95 % or higher, neutral to phenolphthalein,
and containing only volatile denaturants, 95 mL plus 5 mL of water.
13.2 Ethyl Alcohol, Neutral (absolute) —Freshly boiled absolute ethyl alcohol, neutral to phenolphthalein.
D820 − 93 (2016)
14. Procedure
14.1 Weigh 2 6 0.001 g of the sample into a 250-mL beaker. Add 100 mL of neutral ethyl alcohol (95 %), cover the beaker,
and heat on the steam bath with frequent stirring and maceration of the sample until completely disintegrated. Let settle and filter
the supernatant liquid through a tared Gooch crucible with a glass wool pad, with suction into a tared 300-mL Erlenmeyer flask,
retaining as much of the residue as possible in the beaker. Repeat this extraction three times with 25-mL portions of hot neutral
ethyl alcohol (95 %
...
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