ASTM D5559-95(2023)

Standard Test Method for Determination of Acidity as Free Fatty Acids/Acid Number in the Absence of Ammonium or Triethanolamine Soaps in Sulfonated and Sulfated Oils

SIGNIFICANCE AND USE
2.1 This test method is intended for use in the determination of the acidity as free fatty acids in the absence of ammonium or triethanolamine soaps in sulfonated and sulfated oils for the purpose of quality assurance.
SCOPE
1.1 This test method covers the determination of the acidity as free fatty acids existing in a sample of sulfonated or sulfated oil, or both, by titrating the sample dissolved in a solvent. It is not applicable in the presence of ammonium or triethanolamine soaps or salts or other compounds that do not react neutral to phenolphthalein when dissolved in alcohol.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.

General Information

• Status: Published
• Publication Date: 30-Nov-2023
• ICS: 71.080.40 - Organic acids
• Technical Committee: D31 - Leather
• Drafting Committee: D31.08 - Fats and Oils

Relations

• Replaces: ASTM D5559-95(2017) - Standard Test Method for Determination of Acidity as Free Fatty Acids/Acid Number in the Absence of Ammonium or Triethanolamine Soaps in Sulfonated and Sulfated Oils
• Effective Date: 01-Dec-2023

Overview

ASTM D5559-95(2023): Standard Test Method for Determination of Acidity as Free Fatty Acids/Acid Number in the Absence of Ammonium or Triethanolamine Soaps in Sulfonated and Sulfated Oils is an important international standard maintained by ASTM International. This test method specifies procedures for measuring the acidity in sulfonated and sulfated oils, focusing on cases where ammonium or triethanolamine soaps are absent. The determination of acidity, specifically as free fatty acids, is critical for the quality assurance of oils used in various industrial applications, including leather manufacturing and specialty chemical production.

Key Topics

• Scope: The standard covers the determination of free fatty acids by titration using sodium or potassium hydroxide, in a sample of sulfonated or sulfated oils.
• Exclusions: The method is not suitable if ammonium or triethanolamine soaps or salts are present, or if the sample contains substances that do not exhibit a neutral reaction with phenolphthalein in alcohol.
• Reference Units: All measurements are to be made and reported in SI units.
• Procedure: Oils are dissolved in an alcohol-ether mixture and titrated using a phenolphthalein indicator.
• Calculation: Acidity is expressed as the acid number or as percent free fatty acids, calculated based on titrant volume and concentration relative to sample weight.
• Quality Assurance: The method supports monitoring and ensuring product consistency in industrial processes.
• Compliance: Developed in alignment with international standardization principles set by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

Applications

• Leather Industry: Used for routine analysis of sulfonated and sulfated oils that are key components in leather processing, ensuring oils meet strict quality requirements for product consistency.
• Chemical Manufacturing: Ensures sulfonated and sulfated oils used as surfactants, lubricants, or chemical intermediates maintain controlled acidity, preventing unwanted reactions in downstream applications.
• Product Development and Research: Provides reliable methodology for researchers and product developers working with specialty oils to monitor and control free fatty acid content.
• Quality Control Laboratories: Supports quality control and assurance teams in verifying that oils comply with internal specifications and industry standards.
• Regulatory Compliance: Allows manufacturers and laboratories to document adherence to globally recognized test methods, supporting import and export activities.

Related Standards

• ASTM D974: Test Method for Acid and Base Number by Color-Indicator Titration, commonly used for petroleum products and lubricants.
• ASTM D2074: Standard Test Method for Total, Primary, Secondary, and Tertiary Amine Values of Fatty Amines by Titration.
• ISO 660: Animal and vegetable fats and oils - Determination of acid value and acidity.
• ASTM D31 Standards: Related to fat and oil analysis, particularly for the leather and related industries.

Keywords: ASTM D5559, acidity determination, free fatty acids, acid number, sulfonated oils, sulfated oils, phenolphthalein titration, leather industry, quality assurance, oil analysis, international standard.

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: D5559 − 95 (Reapproved 2023)
Standard Test Method for
Determination of Acidity as Free Fatty Acids/Acid Number in
the Absence of Ammonium or Triethanolamine Soaps in
Sulfonated and Sulfated Oils
This standard is issued under the fixed designation D5559; 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 3.3 Sodium Hydroxide, Standard Solution (0.5 N)—
Prepare and standardize a 0.5 N solution of sodium hydroxide
1.1 This test method covers the determination of the acidity
(NaOH). Potassium hydroxide (KOH) may be substituted for
as free fatty acids existing in a sample of sulfonated or sulfated
NaOH.
oil, or both, by titrating the sample dissolved in a solvent. It is
not applicable in the presence of ammonium or triethanolamine
4. Procedure
soaps or salts or other compounds that do not react neutral to
4.1 The procedure consists of titrating a solution of the
phenolphthalein when dissolved in alcohol.
sample in a mixture of alcohol and ether in the presence of
1.2 The values stated in SI units are to be regarded as
phenolphthalein indicator. Dissolve 10 g of the sample in an
standard. No other units of measurement are included in this
alcohol-ether mixture, add five drops of phenolphthalein indi-
standard.
cator solution, and titrate the solution with 0.5 N NaOH or
1.3 This standard does not purport to address all of the
KOH solution until the pink color persists after vigorous
safety concerns, if any, associated with its use. It is the
shaking.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 5. Calculation
mine the applicability of regulatory limitations prior to use.
5.1 Calculate the acidity as free fatty acids, as follows:
1.4 This international standard was developed in accor-
K 5 ~C × E!/W (1)
dance with internationally recognized principles on standard-
or
ization established in the Decision on Principles for the
% free fatty acids 5 0.503 × K (2)
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
where:
Barriers to Trade (TBT) Committee.
K = acid number, mg of KOH/g,
C = mL of NaOH or KOH solution required for titration of
2. Significance and Use
the sample,
2.1 This test method is intended for use in the determination
E = strength of NaOH or KOH solution, mg of KOH/mL,
of the acidity as free fatty acids in the absence of ammonium
and
or triethanolamine soaps in sulfonated and sulfated
...