ASTM D1240-14(2018)
(Test Method)Standard Test Methods for Rosin Acids Content of Pine Chemicals, Including Rosin, Tall Oil, and Related Products
Standard Test Methods for Rosin Acids Content of Pine Chemicals, Including Rosin, Tall Oil, and Related Products
SIGNIFICANCE AND USE
4.1 This is a revision of the method for measuring rosin acids content combines the three major ways of determining the rosin acids content of pine chemicals products into a single method.
4.1.1 For materials containing less than 15 % rosin, the modified Glidden procedure has gained acceptance. For materials containing more than 15 % rosin the modified Wolfe Method is preferred. The modified Wolfe and modified Glidden procedures differ only in their details. They have been combined here into a single procedure. This procedure can be run using either a potentiometer or an internal indicator to determine the end point of the titration. Use of a potentiometer is preferred and is the referee method. Use of an internal indicator is the principal alternative method. They will be referred to as the Potentiometric Method and the Internal Indicator Method.
SCOPE
1.1 These test methods cover the determination of rosin acids in tall oil, tall oil fatty acid, tall oil rosin, and other pine chemicals products.
1.2 These test methods may not be applicable to adducts or derivatives of rosin, fatty acid, or other pine chemicals products.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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.
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Standards Content (Sample)
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: D1240 − 14 (Reapproved 2018)
Standard Test Methods for
Rosin Acids Content of Pine Chemicals, Including Rosin,
Tall Oil, and Related Products
This standard is issued under the fixed designation D1240; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 These test methods cover the determination of rosin
acids in tall oil, tall oil fatty acid, tall oil rosin, and other pine
3. Summary of Test Method
chemicals products.
3.1 The rosin acids content is determined by one of two
1.2 These test methods may not be applicable to adducts or
procedures; by selective esterification of fatty acids to form
derivatives of rosin, fatty acid, or other pine chemicals prod-
methylestersfollowedbytitrationoftheunreactedrosinacids,
ucts.
by selective esterification of fatty acids to form butyl esters
1.3 The values stated in SI units are to be regarded as the
followed by titration of the unreacted rosin acids.
standard. The values given in parentheses are for information
4. Significance and Use
only.
4.1 This is a revision of the method for measuring rosin
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the acids content combines the three major ways of determining
the rosin acids content of pine chemicals products into a single
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- method.
4.1.1 For materials containing less than 15% rosin, the
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor- modified Glidden procedure has gained acceptance. For mate-
rials containing more than 15% rosin the modified Wolfe
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the Methodispreferred.ThemodifiedWolfeandmodifiedGlidden
procedures differ only in their details. They have been com-
Development of International Standards, Guides and Recom-
bined here into a single procedure. This procedure can be run
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. using either a potentiometer or an internal indicator to deter-
mine the end point of the titration. Use of a potentiometer is
2. Referenced Documents
preferredandistherefereemethod.Useofaninternalindicator
is the principal alternative method. They will be referred to as
2.1 ASTM Standards:
the Potentiometric Method and the Internal Indicator Method.
D1585Test Methods for Fatty Acids Content of Pine
Chemicals, Including Rosin, Tall Oil, and Related Prod-
5. Reagents
ucts
E70Test Method for pH of Aqueous Solutions With the 5.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
Glass Electrode
E177Practice for Use of the Terms Precision and Bias in all reagents shall conform to the specifications of the Commit-
tee onAnalytical Reagents of theAmerican Chemical Society
ASTM Test Methods
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 D01 on
sufficiently high purity to permit its use without lessening the
Paint and Related Coatings, Materials, and Applications and are the direct
accuracy of the determination.
responsibility of Subcommittee D01.34 on Pine Chemicals and Hydrocarbon
Resins.
Current edition approved June 1, 2018. Published June 2018. Originally
approved in 1952. Last previous edition approved in 2014 as D1240–14. DOI: Reagent Chemicals, American Chemical Society Specifications, American
10.1520/D1240-14R18. 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. Pharmaceutical 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
D1240 − 14 (2018)
5.2 Unless otherwise indicated, references to water shall be in methanol (CH OH) and dilute to 1 L with methanol.
understood to mean deionized or distilled water. Standardize to 60.001 N with potassium acid phthalate
(C H COOKCOOH) in 60 mLof water followed by 40 mLof
6 4
6. Preparation of Sample
methanol; 2.553 g of potassium acid phthalate will be neutral-
ized by 25.00 mL of 0.5 N KOH solution. Protect the
6.1 Homogeneous liquid materials may be used without
standardized solution against evaporation and absorption of
further preparation.
carbon dioxide (CO ) from the air. Restandardize the solution
6.2 Nonhomogeneous liquid materials should be heated
frequently, either potentiometrically or colorimetrically, using
until they are homogeneous, then a portion taken for analysis.
phenolphthalein as the indicator.
6.3 Solid samples are subject to surface oxidation which
10.1.1 Forfattyacidscontaininglowconcentrationsofrosin
may affect the results. Prepare the sample for analysis by
acids, 0.1 N alcoholic potassium hydroxide may give superior
chippingsmallpiecesfromafreshlyexposedsurfaceofalump
results.
or lumps and crush to a coarse powder to facilitate weighing
10.2 Ethanol (95 %)—Denatured alcohol conforming to
and solution. Prepare fresh on the same day, prior to weighing,
Formula No. 3A or No. 30 of the U.S. Bureau of Internal
in order to avoid changes due to surface oxidation of crushed
Revenue, neutralized by the addition of KOH.
rosin on exposure to the air.
10.3 Methanol (99.5%).
ROSIN ACIDS CONTENT BY THE
10.4 Methyl Sulfuric Acid Solution—Slowly pour 100 g of
POTENTIOMETRIC METHOD
concentrated sulfuric acid (H SO sp gr 1.82 to 1.84), while
2 4
(Referee Method)
stirring constantly, into 400 g of methanol. Extreme caution
should be taken while preparing the methyl sulfuric acid.
7. Scope
Adding sulfuric acid too rapidly may cause the methanol to
7.1 Thistestmethodcoversthedeterminationofrosinacids
flash out of its container. Store the methyl sulfuric acid in a
content of tall oil rosin, tall oil fatty acid, and other pine
glass-stoppered bottle.
chemicals products, where the most reproducible results are
10.5 Toluene.
desired. By using the potentiometric inflection end points, the
error due to colorimetric end points is avoided.
11. Procedure
11.1 Choose the amount of sample so that the second
8. Summary of Test Method
titrationwillconsumebetween10and30mLofKOHsolution.
8.1 Asampleisrefluxedwithmethylsulfuricacidtoesterify
For rosin acids, this will be about5gof material. For fatty
the fatty acids. The rosin acids and sulfuric acid are then
acidscontaininglessthan15%rosin,thiswillbeabout40gof
titrated potentiometrically, and the rosin acids content calcu-
material. For fatty acids containing less than 3% rosin acids
lated from the difference between the two inflection points
titrating with 0.1 N KOH may give superior results. Table 1
obtained.
gives suggested amounts of material to use. Weigh the sample
to the nearest 0.001 g in a 250-mL or 500-mL (<15 % rosin
9. Apparatus
samples) flask.
9.1 pH Meter—An indicating potentiometer having a limit
11.2 Dissolve the sample in 100 mL of methanol in a
of error not greater than 60.1 pH over a range from pH 1 to
250-mLflask (or 150 mLmethanol for 500-mLflask with 40 g
pH13, using an alkali-resistant glass electrode and a saturated
sample). If the sample has a high rosin content it may be
calomel half-cell. The pH meter shall conform to the require-
helpfulfirsttodissolveitin25mLoftoluenebeforeaddingthe
ments of Test Method E70. Alternatively, an automatic poten-
methanol. For material believed to contain more than 15%
tiometric titrator may be used.
rosin acid, that is, high in rosin, add 5 mL of methyl sulfuric
9.2 Stirrer, magnetic, equipped with
acid, connect the flask assembly, and reflux the solution for 2
poly(tetrafluoroethylene)-coated stir bar.
to20min.(Solidsamplesmustbeinsolutionbeforebeginning
9.3 Buret, 50-mL capacity, with 0.
...
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: D1240 − 14 (Reapproved 2018)
Standard Test Methods for
Rosin Acids Content of Pine Chemicals, Including Rosin,
Tall Oil, and Related Products
This standard is issued under the fixed designation D1240; 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 E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 These test methods cover the determination of rosin
acids in tall oil, tall oil fatty acid, tall oil rosin, and other pine
3. Summary of Test Method
chemicals products.
3.1 The rosin acids content is determined by one of two
1.2 These test methods may not be applicable to adducts or
procedures; by selective esterification of fatty acids to form
derivatives of rosin, fatty acid, or other pine chemicals prod-
methyl esters followed by titration of the unreacted rosin acids,
ucts.
by selective esterification of fatty acids to form butyl esters
1.3 The values stated in SI units are to be regarded as the
followed by titration of the unreacted rosin acids.
standard. The values given in parentheses are for information
4. Significance and Use
only.
1.4 This standard does not purport to address all of the 4.1 This is a revision of the method for measuring rosin
acids content combines the three major ways of determining
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- the rosin acids content of pine chemicals products into a single
method.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 4.1.1 For materials containing less than 15 % rosin, the
modified Glidden procedure has gained acceptance. For mate-
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard- rials containing more than 15 % rosin the modified Wolfe
Method is preferred. The modified Wolfe and modified Glidden
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- procedures differ only in their details. They have been com-
mendations issued by the World Trade Organization Technical bined here into a single procedure. This procedure can be run
using either a potentiometer or an internal indicator to deter-
Barriers to Trade (TBT) Committee.
mine the end point of the titration. Use of a potentiometer is
2. Referenced Documents
preferred and is the referee method. Use of an internal indicator
is the principal alternative method. They will be referred to as
2.1 ASTM Standards:
the Potentiometric Method and the Internal Indicator Method.
D1585 Test Methods for Fatty Acids Content of Pine
Chemicals, Including Rosin, Tall Oil, and Related Prod-
5. Reagents
ucts
5.1 Purity of Reagents—Reagent grade chemicals shall be
E70 Test Method for pH of Aqueous Solutions With the
Glass Electrode used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
E177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods 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 D01 on
sufficiently high purity to permit its use without lessening the
Paint and Related Coatings, Materials, and Applications and are the direct
accuracy of the determination.
responsibility of Subcommittee D01.34 on Pine Chemicals and Hydrocarbon
Resins.
Current edition approved June 1, 2018. Published June 2018. Originally
approved in 1952. Last previous edition approved in 2014 as D1240 – 14. DOI: Reagent Chemicals, American Chemical Society Specifications, American
10.1520/D1240-14R18. 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. Pharmaceutical 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
D1240 − 14 (2018)
5.2 Unless otherwise indicated, references to water shall be in methanol (CH OH) and dilute to 1 L with methanol.
understood to mean deionized or distilled water. Standardize to 60.001 N with potassium acid phthalate
(C H COOKCOOH) in 60 mL of water followed by 40 mL of
6 4
6. Preparation of Sample
methanol; 2.553 g of potassium acid phthalate will be neutral-
ized by 25.00 mL of 0.5 N KOH solution. Protect the
6.1 Homogeneous liquid materials may be used without
standardized solution against evaporation and absorption of
further preparation.
carbon dioxide (CO ) from the air. Restandardize the solution
6.2 Nonhomogeneous liquid materials should be heated
frequently, either potentiometrically or colorimetrically, using
until they are homogeneous, then a portion taken for analysis.
phenolphthalein as the indicator.
6.3 Solid samples are subject to surface oxidation which
10.1.1 For fatty acids containing low concentrations of rosin
may affect the results. Prepare the sample for analysis by
acids, 0.1 N alcoholic potassium hydroxide may give superior
chipping small pieces from a freshly exposed surface of a lump
results.
or lumps and crush to a coarse powder to facilitate weighing
10.2 Ethanol (95 %)—Denatured alcohol conforming to
and solution. Prepare fresh on the same day, prior to weighing,
Formula No. 3A or No. 30 of the U.S. Bureau of Internal
in order to avoid changes due to surface oxidation of crushed
Revenue, neutralized by the addition of KOH.
rosin on exposure to the air.
10.3 Methanol (99.5 %).
ROSIN ACIDS CONTENT BY THE
10.4 Methyl Sulfuric Acid Solution—Slowly pour 100 g of
POTENTIOMETRIC METHOD
concentrated sulfuric acid (H SO sp gr 1.82 to 1.84), while
2 4
(Referee Method)
stirring constantly, into 400 g of methanol. Extreme caution
should be taken while preparing the methyl sulfuric acid.
7. Scope
Adding sulfuric acid too rapidly may cause the methanol to
7.1 This test method covers the determination of rosin acids
flash out of its container. Store the methyl sulfuric acid in a
content of tall oil rosin, tall oil fatty acid, and other pine
glass-stoppered bottle.
chemicals products, where the most reproducible results are
10.5 Toluene.
desired. By using the potentiometric inflection end points, the
error due to colorimetric end points is avoided.
11. Procedure
8. Summary of Test Method 11.1 Choose the amount of sample so that the second
titration will consume between 10 and 30 mL of KOH solution.
8.1 A sample is refluxed with methyl sulfuric acid to esterify
For rosin acids, this will be about 5 g of material. For fatty
the fatty acids. The rosin acids and sulfuric acid are then
acids containing less than 15 % rosin, this will be about 40 g of
titrated potentiometrically, and the rosin acids content calcu-
material. For fatty acids containing less than 3 % rosin acids
lated from the difference between the two inflection points
titrating with 0.1 N KOH may give superior results. Table 1
obtained.
gives suggested amounts of material to use. Weigh the sample
to the nearest 0.001 g in a 250-mL or 500-mL (<15 % rosin
9. Apparatus
samples) flask.
9.1 pH Meter—An indicating potentiometer having a limit
11.2 Dissolve the sample in 100 mL of methanol in a
of error not greater than 60.1 pH over a range from pH 1 to
250-mL flask (or 150 mL methanol for 500-mL flask with 40 g
pH 13, using an alkali-resistant glass electrode and a saturated
sample). If the sample has a high rosin content it may be
calomel half-cell. The pH meter shall conform to the require-
helpful first to dissolve it in 25 mL of toluene before adding the
ments of Test Method E70. Alternatively, an automatic poten-
methanol. For material believed to contain more than 15 %
tiometric titrator may be used.
rosin acid, that is, high in rosin, add 5 mL of methyl sulfuric
9.2 Stirrer, magnetic, equipped with
acid, connect the flask assembly, and reflux the solution for 2
poly(tetrafluoroethylene)-coated stir bar.
to 20 min. (Solid samples must be in solution before beginning
9.3 Buret, 50-mL capacity, with 0.1-mL divisions. The
reflux.) For materials believed to contain concentrations of
so-called automatic buret is preferable as its use
...
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: D1240 − 14 D1240 − 14 (Reapproved 2018)
Standard Test Methods for
Rosin Acids Content of Pine Chemicals, Including Rosin,
Tall Oil, and Related Products
This standard is issued under the fixed designation D1240; 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 the determination of rosin acids in tall oil, tall oil fatty acid, tall oil rosin, and other pine chemicals
products.
1.2 These test methods may not be applicable to adducts or derivatives of rosin, fatty acid, or other pine chemicals products.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 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.
2. Referenced Documents
2.1 ASTM Standards:
D1585 Test Methods for Fatty Acids Content of Pine Chemicals, Including Rosin, Tall Oil, and Related Products
E70 Test Method for pH of Aqueous Solutions With the Glass Electrode
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Summary of Test Method
3.1 The rosin acids content is determined by one of two procedures; by selective esterification of fatty acids to form methyl
esters followed by titration of the unreacted rosin acids, by selective esterification of fatty acids to form butyl esters followed by
titration of the unreacted rosin acids.
4. Significance and Use
4.1 This is a revision of the method for measuring rosin acids content combines the three major ways of determining the rosin
acids content of pine chemicals products into a single method.
4.1.1 For materials containing less than 15 % rosin, the modified Glidden procedure has gained acceptance. For materials
containing more than 15 % rosin the modified Wolfe Method is preferred. The modified Wolfe and modified Glidden procedures
differ only in their details. They have been combined here into a single procedure. This procedure can be run using either a
potentiometer or an internal indicator to determine the end point of the titration. Use of a potentiometer is preferred and is the
referee method. Use of an internal indicator is the principal alternative method. They will be referred to as the Potentiometric
Method and the Internal Indicator Method.
5. Reagents
5.1 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
These test methods are under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and are the direct responsibility of
Subcommittee D01.34 on Pine Chemicals and Hydrocarbon Resins.
Current edition approved July 1, 2014June 1, 2018. Published August 2014June 2018. Originally approved in 1952. Last previous edition approved in 20122014 as
D1240 – 12.D1240 – 14. DOI: 10.1520/D1240-14.10.1520/D1240-14R18.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1240 − 14 (2018)
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.
5.2 Unless otherwise indicated, references to water shall be understood to mean deionized or distilled water.
6. Preparation of Sample
6.1 Homogeneous liquid materials may be used without further preparation.
6.2 Nonhomogeneous liquid materials should be heated until they are homogeneous, then a portion taken for analysis.
6.3 Solid samples are subject to surface oxidation which may affect the results. Prepare the sample for analysis by chipping
small pieces from a freshly exposed surface of a lump or lumps and crush to a coarse powder to facilitate weighing and solution.
Prepare fresh on the same day, prior to weighing, in order to avoid changes due to surface oxidation of crushed rosin on exposure
to the air.
ROSIN ACIDS CONTENT BY THE POTENTIOMETRIC METHOD
(Referee Method)
7. Scope
7.1 This test method covers the determination of rosin acids content of tall oil rosin, tall oil fatty acid, and other pine chemicals
products, where the most reproducible results are desired. By using the potentiometric inflection end points, the error due to
colorimetric end points is avoided.
7. Scope
7.1 This test method covers the determination of rosin acids content of tall oil rosin, tall oil fatty acid, and other pine chemicals
products, where the most reproducible results are desired. By using the potentiometric inflection end points, the error due to
colorimetric end points is avoided.
8. Summary of Test Method
8.1 A sample is refluxed with methyl sulfuric acid to esterify the fatty acids. The rosin acids and sulfuric acid are then titrated
potentiometrically, and the rosin acids content calculated from the difference between the two inflection points obtained.
9. Apparatus
9.1 pH Meter—An indicating potentiometer having a limit of error not greater than 60.1 pH over a range from pH 1 to pH 13,
using an alkali-resistant glass electrode and a saturated calomel half-cell. The pH meter shall conform to the requirements of Test
Method E70. Alternatively, an automatic potentiometric titrator may be used.
9.2 Stirrer, magnetic, equipped with poly(tetrafluoroethylene)-coated stir bar.
9.3 Buret, 50-mL capacity, with 0.1-mL divisions. The so-called automatic buret is preferable as its use minimizes errors due
to evaporation. The automatic buret should be guarded with soda-lime tubes against the absorption of CO from the air.
9.4 Erlenmeyer Flask, 250 mL, 500 mL, or larger of a chemically resistant glass with a standard-taper 24/40 joint.
9.5 Condenser, water-cooled, equipped with a joint fitting the flask described in accordance with 9.4.
10. Reagents
10.1 Alcoholic Alkali, Standard Solution (0.5 N)—Dissolve 33 g of potassium hydroxide (KOH), preferably in pellet form, in
methanol (CH OH) and dilute to 1 L with methanol. Standardize to 60.001 N with potassium acid phthalate (C H COOKCOOH)
3 6 4
in 60 mL of water followed by 40 mL of methanol; 2.553 g of potassium acid phthalate will be neutralized by 25.00 mL of 0.5
N KOH solution. Protect the standardized solution against evaporation and absorption of carbon dioxide (CO ) from the air.
Restandardize the solution frequently, either potentiometrically or colorimetrically, using phenolphthalein as the indicator.
10.1.1 For fatty acids containing low concentrations of rosin acids, 0.1 N alcoholic potassium hydroxide may give superior
results.
10.2 Ethanol (95 %)—Denatured alcohol conforming to Formula No. 3A or No. 30 of the U.S. Bureau of Internal Revenue,
neutralized by the addition of KOH.
10.3 Methanol (99.5 %).
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. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.
D1240 − 14 (2018)
10.4 Methyl Sulfuric Acid Solution—Slowly pour 100 g of concentrated sulfuric acid (H SO sp gr 1.82 to 1.84), while stirring
2 4
constantly, into 400 g of methanol. Extreme caution should be taken while preparing the methyl sulfuric acid. Adding sulfuric acid
too rapidly may cause the methanol to flash out of its container. Store the methyl sulfuric acid in a glass-stoppered bottle.
10.5 Toluene.
11. Procedure
11.1 Choose the amount of sample so that the second titration will consume between 10 and 30 mL of KOH solution. For rosin
acids, this will be about 5 g of material. For fatty acids containing less than 15 % rosin, this will be about 40 g of material. For
fatty acids containing less than 3 % rosin acids titrating with 0.1 N KOH may give superior results. Table 1 gives suggested
amounts of materi
...
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