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 provides a widely recognized procedure for quality assurance testing of oils modified by sulfonation or sulfation. This ASTM International standard outlines a titration method that quantifies acidity, expressed as free fatty acids or acid number, specifically in samples where ammonium or triethanolamine soaps are absent. The methodology ensures that only the relevant acidity is measured, improving the accuracy and reliability of results for industrial and laboratory applications. All values and calculations in this standard use SI units.

Key Topics

• Determination of Free Fatty Acids: The standard details a titration technique employing a sodium or potassium hydroxide standard solution to quantify acid content in sulfonated and sulfated oil samples, dissolved in an alcohol-ether medium.
• Applicability: The method is valid for oils free from ammonium or triethanolamine soaps and other compounds that might react with phenolphthalein in alcohol, ensuring specificity to free fatty acids.
• Quality Assurance: Focused on the precise measurement of oil acidity for manufacturing and laboratory quality control, supporting consistent product characteristics and regulatory compliance.
• Procedure Overview:
  • Samples are dissolved in an alcohol-ether mix.
  • Phenolphthalein is used as an indicator.
  • Titration is conducted with 0.5 N sodium or potassium hydroxide solution, and the acid number is determined from the titration endpoint.
• Compliance and Safety: While addressing measurement techniques, users must establish their own safety, health, and environmental protocols in accordance with applicable regulations.

Applications

This standard is essential for a range of industries dealing with sulfonated or sulfated oils, particularly where free fatty acid determination is critical to product quality and consistency. Common applications include:

• Leather Industry: Used by leather manufacturers and testers to ensure oils used in processing meet required acidity specifications, impacting material characteristics such as softness and durability.
• Industrial Oils and Lubricants: Supports accurate formulation and quality control for oils utilized in various manufacturing settings where sulfonation or sulfation modifies oil properties.
• Laboratory Analysis: Employed in research and development environments focusing on oil modification and performance characterization.
• Quality Control Labs: Provides a standardized approach for routine monitoring of oil quality in accordance with industry and international guidelines.

By facilitating consistent measurement of acidity as free fatty acids, ASTM D5559-95(2023) helps manufacturers and labs ensure their products maintain high standards, avoid quality defects, and meet regulatory demands.

Related Standards

Professionals using ASTM D5559-95(2023) may also refer to the following related ASTM standards and international guidelines:

• ASTM D974 - Standard Test Method for Acid and Base Number by Color-Indicator Titration
• ASTM D664 - Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration
• ASTM D2074 - 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

These standards collectively support comprehensive oil and fat analysis, ensuring reliable quality assessment and value determination for industrial, commercial, and research uses.

Keywords: ASTM D5559, free fatty acids, acid number, sulfonated oils, sulfated oils, quality assurance, leather industry, oil analysis, titration method.

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
...