ASTM D464-95(1999)
(Test Method)Standard Test Methods for Saponification Number of Naval Store Products Including Tall Oil and Other Related Products
Standard Test Methods for Saponification Number of Naval Store Products Including Tall Oil and Other Related Products
SCOPE
1.1 These test methods cover the determination of the saponification number of tall oil and products obtained by the fractionation of tall oil such as rosin, fatty acids and distilled tall oil as defined in Terminology D804. These test methods are also applicable to gum and wood rosin. Two test methods are covered as follows:
1.1.1 Test method using a potentiometric method, and
1.1.2 Test method using an internal indicator method.
1.2 The potentiometric method is suitable for use with both light- and dark-colored test samples. It should be considered the referee method. The internal indicator method is suitable for use only with light- and medium-colored test samples. It should be considered the alternate method.
1.3 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.
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Designation: D 464 – 95 (Reapproved 1999)
Standard Test Methods for
Saponification Number of Naval Store Products Including
Tall Oil and Other Related Products
This standard is issued under the fixed designation D 464; 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 3. Significance and Use
1.1 These test methods cover the determination of the 3.1 These test methods are designed to broaden the scope of
saponification number of tall oil and products obtained by the the previous edition of the test method by the inclusion of tall
fractionation of tall oil such as rosin, fatty acids and distilled oil and tall oil derived products as test materials. Test Methods
tall oil as defined in Terminology D 804. These test methods D 803 currently includes a method for the determination of
are also applicable to gum and wood rosin. Two test methods saponification number. The details of that procedure will be
are covered as follows: deleted when test methods D 803 are revised. Test Methods
1.1.1 Test method using a potentiometric method, and D 803 will reference these test methods.
1.1.2 Test method using an internal indicator method. 3.2 The saponification number is an important property of
1.2 The potentiometric method is suitable for use with both talloilandtheproductsobtainedbythefractionationoftalloil.
light- and dark-colored test samples. It should be considered It is the test method widely used to determine the total acid
the referee method. The internal indicator method is suitable content, both free and combined, of these products.
for use only with light- and medium-colored test samples. It 3.3 The potentiometric test method should be used when the
should be considered the alternate method. most reproducible results are required.
1.3 This standard does not purport to address all of the
4. Preparation of Sample
safety concerns, if any, associated with its use. It is the
4.1 If the sample for analysis is rosin, it shall consist of
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- small pieces of rosin chipped from a freshly exposed part of a
lump or lumps, and thereafter crushed to facilitate weighing
bility of regulatory limitations prior to use.
and dissolution. Prepare the sample the same day on which the
2. Referenced Documents
test is begun in order to avoid changes in properties due to
2.1 ASTM Standards: surface oxidation. Changes are very pronounced on ground
D 803 Test Methods for Testing Tall Oil rosin that has a large surface area exposed to air. Existing rosin
D 804 Terminology Relating to Naval Stores, IncludingTall dust and powdered rosin must not be used.
Oil and Other Related Products 4.2 If the sample is a nonhomogeneous liquid, heat the
E70 Test Method for pH of Aqueous Solutions with the entire sample in a closed container fitted with a capillary vent
Glass Electrode or the equivalent. Some kind of agitation, even if done
occasionally by hand, saves much time. Heat by immersion in
open steam or hot water bath to avoid overheating. When
ThesetestmethodsareunderthejurisdictionofASTMCommitteeD-1onPaint
dealing with crystallized rosin, a higher temperature of ap-
and Related Coatings, Materials, and Applications and are the direct responsibility
proximately 160°C may be needed. Remove samples for
of Subcommittee D01.34 on Naval Stores.
testing only when the entire sample is homogeneous and has
Current edition approved Sept. 15, 1995. Published November 1995. Originally
published as D 464 – 37 T. Last previous edition D 464 – 92.
been well stirred.
Annual Book of ASTM Standards, Vol 06.03.
Annual Book of ASTM Standards, Vol 15.05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 464 – 95 (1999)
5. Purity of Reagents and Water 7.5 Acid, Standard (0.5 N)—Standardize a 0.5 N solution of
HCl to 60.001 N by any accepted procedure.
5.1 Unless otherwise indicated, it is intended that all re-
7.6 Borax Buffer, Standard Solution (0.01 M, pH 9.18 at
agents shall conform to the specifications established by the
25°C)—Dissolve 3.81 6 0.01 g of disodium tetraborate
Committee on Analytical Reagents of the American Chemical
4 (Na B 07·10 H O) in water and dilute to 1 L in a volumetric
2 4 2
Society, wheresuchspecificationsareavailable.Referencesto
flask. Use the special grade of borax prepared specifically for
water shall be understood to mean distilled or deionized water.
use as a pH standard.As an alternative, commercially available
buffer with a pH between 9 and 11 may be used.
POTENTIOMETRIC TEST METHOD (Referee Method)
8. Procedure
6. Apparatus
8.1 Transfer 2.95 to 3.05 g of the sample, weighed to the
6.1 Erlenmeyer Flask, 250-mL, of chemically resistant
nearest 0.001 g, to the Erlenmeyer flask. If necessary, 10 mLof
glass with standard-taper glass joint.
isopropyl alcohol-toluene solution (1:1) can be added to the
6.2 Hot Plates.
flask to predissolve the sample. Using a constant delivery pipet
6.3 Water-Cooled Reflux Condenser, with standard-taper
or volumetric pipet add 50.0 mL of the alkali solution. Add
joint to fit the Erlenmeyer flask.
several PTFE boiling stones or glass beads and connect the
6.4 Buret, with 0.1 mL divisions.
flask to the condenser.
6.5 Stirrer, variable-speed, with a polytetrafluoroethylene
8.2 Place the flask on a hot plate and maintain the solution
(PTFE) coated magnetic stir bar.
at reflux for 1 h.At the end of the reflux time, while the sample
6.6 Delivery or Volumetric Pipet, 50-mL constant.
is still warm, transfer the contents of the Erlenmeyer flask into
6.7 PTFE Boiling Stones, or glass beads.
a 400-mL tall-form beaker rinsing with 100 mL of isopropyl
6.8 Beaker, 400-mL tall-form.
alcohol in three washings. Place samples on a heated surface
6.9 Glass Electrode pH Meter, conforming to the require-
until they can be titrated. In order to avoid highly variable
ments of Test Method E70. Use either standard or alkali-
results, make sure that the temperature of the samples is
resistant electrodes for this test. Alternatively, an automatic
approximately 60 to 70°C when titrated.
potentiometric titrator may be used.
8.3 Titratewith0.5Nacid,recordingtheburetandpHmeter
readings. Sufficient acid may be added initially to bring the pH
7. Reagents
of the solution to about 12. Allow sufficient time for the
7.1 Ethyl Alcohol (95 %) denatured by Formula No. 3A or
electrode system to reach equilibrium. Add acid in 1.0-mL
No. 30 of the U.S. Bureau of Internal Revenue.
portions until the change in pH per addition exceeds 0.3 pH
7.2 Isopropyl Alcohol, Reagent grade.
units. Reduce the additions of acid to 0.1 mL or smaller until
7.3 Toluene, Reagent grade.
the end point has been passed, as indicated by a significant
7.4 Alkali Solution, Standard Alcoholic (0.5 N)—Dissolve
decrease in pH units per 0.1 mL of acid added. Continue the
33 g of potassium hydroxide (KOH), preferably in pellet fo
...
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