ASTM D5768-95

Standard Test Method for Determination of Iodine Value of Tall Oil Fatty Acids

SCOPE
1.1 This test method covers the Wijs procedure for determination of unsaturation (iodine value) of tall oil fatty acids.  
1.2 Iodine value is a measure of the unsaturation of oils and fatty acids and is expressed in terms of the number of centigrams of iodine per gram of sample (weight percent of absorbed iodine).  
1.3 When this test method is used to determine the iodine value of fatty acids having conjugated systems, the result is not a measure of total unsaturated, but rather is an empirical value that affords a comparison of unsaturation. Total unsaturation of conjugated systems may be measured in accordance with Test Method D1541.  
1.4 The test method described here is not reliable for tall oil fatty acids containing an appreciable quantity of rosin.  
1.5 This standard does not purport to address all of the safety concerns, 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

• Status: Historical
• Publication Date: 31-Dec-1994
• ICS: 87.060.20 - Binders
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.34 - Pine Chemicals and Hydrocarbon Resins

Relations

• Replaced By: ASTM D5768-02 - Standard Test Method for Determination of Iodine Value of Tall Oil Fatty Acids
• Effective Date: 10-Dec-2002

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 5768 – 95
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Determination of Iodine Value of Tall Oil Fatty Acids
This standard is issued under the fixed designation D 5768; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope iodine value obtained is empirical since the reagent does not
react stoichiometrically with conjugated unsaturation. Where
1.1 This test method covers the Wijs procedure for deter-
no conjugation is present, the iodine value obtained is a
mination of unsaturation (iodine value) of tall oil fatty acids.
measure of the total unsaturation. By using proper specimen
1.2 Iodine value is a measure of the unsaturation of oils and
weights, the empirical values obtained are useful for compara-
fatty acids and is expressed in terms of the number of
tive purposes.
centigrams of iodine per gram of sample (weight percent of
3.4 This test method was developed in order to replace the
absorbed iodine).
hazardous solvent, carbon tetrachloride, used in Test Method
1.3 When this test method is used to determine the iodine
D 1959 with the less hazardous and more available solvent,
value of fatty acids having conjugated systems, the result is not
isooctane. Other solvents, such as cyclohexane, may also be
a measure of total unsaturated, but rather is an empirical value
satisfactory replacements for carbon tetrachloride. As data on
that affords a comparison of unsaturation. Total unsaturation of
the satisfactory use of other solvents becomes available, this
conjugated systems may be measured in accordance with Test
test method will be amended to include those solvents.
Method D 1541.
3.5 This test method should have applicability to fatty acids
1.4 The test method described here is not reliable for tall oil
and oils other than tall oil fatty acid but that possibility has not
fatty acids containing an appreciable quantity of rosin.
been investigated.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Apparatus
responsibility of the user of this standard to establish appro-
4.1 Bottles—Glass-stoppered bottles or Erlenmeyer flasks
priate safety and health practices and determine the applica-
of 250-mL capacity.
bility of regulatory limitations prior to use.
4.2 Pipets—20 and 25-mL capacity.
2. Referenced Documents
5. Reagents
2.1 ASTM Standards:
2 5.1 Purity of Reagents—Reagent grade chemicals shall be
D 1193 Specification for Reagent Water
used in all tests unless otherwise specified. Unless otherwise
D 1541 Test Method for Total Iodine Value of Drying Oils
3 indicated, it is intended that all reagents shall conform to the
and Their Derivatives
Specifications of the Committee on Analytical Reagents of the
D 1959 Test Method for Iodine Value of Drying Oils and
3 American Chemical Society, where such specifications are
Fatty Acids
available. Other grades may be used provided it is first
3. Significance and Use ascertained that the reagent is of sufficiently high purity to
permit its use without lessening the accuracy of the determi-
3.1 The iodine value of a fatty acid product is a measure of
nation.
the unsaturated fatty acid content of that product and conse-
5.2 Purity of Water—Unless otherwise indicated, references
quently a measure of the ease of oxidation or drying capacity
to water shall be understood to mean reagent water conforming
of that fatty acid product.
to Type I of Specification D 1193.
3.2 This test method measures the unsaturation as iodine
5.3 Acetic Acid (Glacial) 17.4 M—Verify the absence of
value by addition of an iodine/chlorine reagent. The amount of
substances reducing permanganate as follows: Dilute 2 mL of
reagent absorbed is determined by back titrating the excess
the acid with 10 mL of water and add 0.1 mL of 0.1 N
reagent and comparing it to a blank determination.
potassium permanganate (KMnO ) solution. The pink color
3.3 In samples containing conjugated double bonds, the 4
Reagent Chemicals, American Chemical Society Specifications, American
This test method is under the jurisdiction of ASTM Committee D-1 on Paint
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
and Related Coatings, Materials, and Applications and is the direct responsibility of
listed by the American Chemical Society, see Analar Standards for Laboratory
Subcommittee D01.34 on Naval Stores.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Current edition approved Sept. 15, 1995. Published November 1995.
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
Annual Book of ASTM Standards, Vol 11.01.
MD.
Annual Book of ASTM Standards, Vol 06.03.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5768
TABLE 1 Specimen Weights
should not be entirely discharged at the end of 2 h.
5.4 Isooctane. Normal Fatty Acids, 100 to Conjugated Fatty Acids, 115 to
Iodine Value
150 % Excess of Reagent, g 135 % Excess of Reagent, g
5.5 Chlorine (99.8 % Cl)—Precaution: See Note 1. Com-
Less than 3 10
mercial grades of chlorine available in cylinders may be used,
3 8.46 to 10.57
provided the gas is dried by passing through concentrated
5 5.08 to 6.35
sulfuric acid (H SO , sp gr 1.84) before passing it into the
10 2.54 to 3.17
2 4
20 0.85 to 1.59
iodine solution. Alternatively, the chlorine may be prepared by
40 0.64 to 0.79
allowing concentrated hydrochloric acid (HCl, sp gr 1.19) to
60 0.42 to 0.53
drop onto potassium permanganate (KMnO ) or onto a mixture
80 0.32 to 0.40 0.34 to 0.37
90 0.28 to 0.35 0.30 to 0.33
of KMnO and manganese dioxide (MnO ). Dry the gas thus
4 2
100 0.25 to 0.32 0.27 to 0.30
generated by passing it through concentrated H SO .
2 4
110 0.23 to 0.29 0.24 to 0.27
120 0.21 to 0.26 0.22 to 0.25
NOTE 1—Precaution: Extremely hazardous. For specific hazard infor-
130 0.20 to 0.24 0.21 to 0.23
mation and guidance, see supplier’s Material Safety Data sheets.
140 0.18 to 0.23 0.19 to 0.21
150 0.17 to 0.21 0.18 to 0.20
5.6 Potassium Iodide Solution (150 g/L)—Dissolve 150 g of
160 0.16 to 0.20 0.17 to 0.18
potassium iodide (KI) in water and dilut
...