ASTM D5350-95(2019)

Standard Test Method for Determination of Organically Combined Sulfuric Anhydride by Titration, Test Method A

SIGNIFICANCE AND USE
3.1 This test method is intended for the determination of organically combined sulfuric anhydride in sulfated oils.
SCOPE
1.1 This test method covers the determination of the organically combined sulfuric anhydride existing in a sample of sulfated oil by boiling the sample with sulfuric acid and determining the acidity of the reaction mixture. This test method is applicable only to oils that split off their combined SO3 upon boiling with mineral acids and that do not contain compounds that cannot be accurately titrated in water solution with methyl orange as the indicator. This test method was derived from Test Methods D500, Sections 15 through 19.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered 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: 31-Mar-2019
• ICS: 71.080.01 - Organic chemicals in general
• Technical Committee: D31 - Leather
• Drafting Committee: D31.08 - Fats and Oils

Relations

• Replaces: ASTM D5350-95(2012) - Standard Test Method for Determination of Organically Combined Sulfuric Anhydride by Titration, Test Method A
• Effective Date: 01-Apr-2019
• Refers: ASTM D500-95(2009) - Standard Test Methods of Chemical Analysis of Sulfonated and Sulfated Oils
• Effective Date: 01-Oct-2009
• Refers: ASTM D500-95(2003) - Standard Test Methods of Chemical Analysis of Sulfonated and Sulfated Oils
• Effective Date: 15-Apr-1995
• Refers: ASTM D500-95 - Standard Test Methods of Chemical Analysis of Sulfonated and Sulfated Oils
• Effective Date: 01-Jan-1995
• Referred By: ASTM D5553-95(2019) - Standard Test Method for Determination of the Unsaponifiable Nonvolatile Matter in Sulfated Oils
• Effective Date: 01-Apr-2019
• Referred By: ASTM D5562-95(2018) - Standard Test Method for Determination of the Acidity as Free Fatty Acids/Acid Number in the Presence of Ammonium or Triethanolamine Soaps
• Effective Date: 01-Apr-2019
• Referred By: ASTM D5564-95(2018) - Standard Test Method for Determination of the Total Ammonia Contained in Sulfonated or Sulfated Oils
• Effective Date: 01-Apr-2019
• Referred By: ASTM D5353-95(2019) - Standard Test Method for Determination of Total Desulfated Fatty Matter
• Effective Date: 01-Apr-2019

Overview

ASTM D5350-95(2019) - Standard Test Method for Determination of Organically Combined Sulfuric Anhydride by Titration, Test Method A is an internationally recognized procedure developed by ASTM International for the quantitative analysis of organically combined sulfuric anhydride (SO₃) in sulfated oils. This standard method is particularly applicable to sulfated oils used in leather processing and other industrial applications. It provides a reliable approach for determining organically combined SO₃ by boiling the sample with sulfuric acid, then titrating the resultant mixture to assess acidity. Its utility is limited to oils that will reliably split off their combined SO₃ when boiled with mineral acids and that do not contain compounds which may interfere with accurate titration using methyl orange indicator.

Key Topics

• Purpose and Scope

  • Measurement of organically combined sulfuric anhydride in sulfated oils
  • Applicable only to suitable oils for reliable titration and splitting of SO₃

• Method Overview

  • Sample Preparation: The oil sample is boiled with sulfuric acid to release organically combined SO₃.
  • Titration: The acidity of the resulting mixture is measured, using methyl orange as the indicator, and titrated with standardized sodium hydroxide solutions.
  • Calculations: The increase in acidity is determined, enabling calculation of the percentage of organically combined sulfuric anhydride.

• Required Apparatus and Reagents

  • Borosilicate glass Erlenmeyer flask (300 mL), air condenser, and chemically resistant glass beads
  • Standard solutions: Sodium hydroxide (NaOH), sulfuric acid (H₂SO₄), methyl orange, ethyl ether, and solid sodium chloride (NaCl)

• Documentation and International Relevance

  • Developed in accordance with the WTO Technical Barriers to Trade (TBT) principles

Applications

ASTM D5350-95(2019) is essential in industries where control and quality assurance of sulfated oils are critical, especially:

• Leather Manufacturing: The method ensures that sulfated oils used in tanning and finishing have the correct levels of organically combined sulfuric anhydride, which impacts processing and finished product quality.
• Chemical and Materials Testing Laboratories: Utilized as a reference method for routine quality control and research related to oil sulfation levels.
• Compliance and Regulatory Testing: Facilitates conformity to international trade requirements and industry best practices.

The test method helps in:

• Assessing chemical treatments in oil processing
• Verifying supplier specifications
• Supporting research and development for improved oil formulations

Related Standards

• ASTM D500 - Test Methods of Chemical Analysis of Sulfonated and Sulfated Oils: ASTM D5350 was derived from certain sections of this broader analytical standard and remains closely related in application.
• International Standards on Sulfated Oils and Leather Chemicals: Relevant where materials are traded internationally or where regulatory compliance is necessary.
• Guidelines from the World Trade Organization (WTO) TBT Committee: Ensures harmonization with international standardization principles.

Summary

Adoption of ASTM D5350-95(2019) enables reliable determination of organically combined sulfuric anhydride in sulfated oils through a proven titration method. The standard is widely accepted in the global leather and chemical industries and supports robust quality control, regulatory compliance, and international trade. Organizations relying on consistent oil quality or compliance with technical barriers to trade should implement this method as part of their laboratory protocols.

Keywords: ASTM D5350, sulfated oils, sulfuric anhydride, titration, leather chemicals, laboratory test methods, chemical analysis, international standard, quality control.

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: D5350 − 95 (Reapproved 2019)
Standard Test Method for
Determination of Organically Combined Sulfuric Anhydride
by Titration, Test Method A
This standard is issued under the fixed designation D5350; 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. Significance and Use
3.1 This test method is intended for the determination of
1.1 This test method covers the determination of the organi-
organically combined sulfuric anhydride in sulfated oils.
cally combined sulfuric anhydride existing in a sample of
sulfated oil by boiling the sample with sulfuric acid and
4. Apparatus
determining the acidity of the reaction mixture. This test
4.1 The apparatus required consists of a glass flask provided
method is applicable only to oils that split off their combined
with a glass stopper and an air condenser. The connection
SO upon boiling with mineral acids and that do not contain
between the flask and the condenser shall be a ground joint.
compounds that cannot be accurately titrated in water solution
Perforated glass beads shall be used to prevent bumping.
with methyl orange as the indicator. This test method was
4.1.1 Flask, an Erlenmeyer flask (Fig. 1) made of borosili-
derived from Test Methods D500, Sections 15 through 19.
cate glass, having a capacity of approximately 300 mL and
1.2 The values stated in SI units are to be regarded as provided with a glass stopper.
standard. The values given in parentheses after SI units are 4.1.2 Condenser—The condenser required consists of a
glass tube, 915 mm (36 in.) in length, and 8 mm ( ⁄16 in.) in
provided for information only and are not considered standard.
outside diameter. The lower end of the tube shall be flared and
1.3 This standard does not purport to address all of the
ground to fit the mouth of the Erlenmeyer flask.
safety concerns, if any, associated with its use. It is the
4.1.3 Glass Beads, perforated glass beads, made of chemi-
responsibility of the user of this standard to establish appro-
cally resistant glass, approximately 4 mm ( ⁄32 in.) in diameter.
priate safety, health, and environmental practices and deter-
Before using, the glass beads shall be boiled thoroughly in
mine the applicability of regulatory limitations prior to use.
several portions of water or until the wash water reacts neutral
1.4 This international standard was developed in accor-
to methyl orange indicator.
dance with internationally recognized principles on standard-
5. Reagents
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5.1 Ethyl Ether.
mendations issued by the World Trade Organization Technical
5.2 MethylOrangeIndicatorSolution(1g/L)—Dissolve 0.1
Barriers to Trade (TBT) Committee.
g of methyl orange in 100 mL of water.
5.3 Sodium Chloride (NaCl), solid.
2. Referenced Documents
5.4 Sodium Hydroxide, Standard Solution (1 N)—
2.1 ASTM Standards:
Accurately prepare and standardize a 1 N sodium hydroxide
D500 Test Methods of ChemicalAnalysis of Sulfonated and
(NaOH) solution. Express the strength or concentration of the
Sulfated Oils
solution as milligrams of KOH per millilitre; 1 mL of 1 N
NaOH solution is equivalent to 56.1 mg of KOH.
5.5 Sodium Hydroxide, Standard Solution (0.5 N)—
This test method is under the jurisdiction ofASTM Committee D31 on Leather
Accurately prepare and standardize a 0.5 N NaOH solution.
and is the direct responsibility of Subcommittee D31.08 on Fats and Oils. This test
Express the strength of the solution as milligrams of KOH per
method was developed in cooperation with the American Leather Chemists Assn.
(Method H 42–1957).
millilitre; 1 mL of 0.5 N NaOH solution is equivalent to 28.05
Current edition approved April 1, 2019. Published April 2019. Originally
mg of KOH.
approved in 1993. Last previous edition approved in 2012 as D5350 – 95(2012).
DOI: 10.1520/D5350-95R19.
5.6 SulfuricAcid,Standard(0.5N)—Accuratelyprepareand
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
standardize a 0.5N sulfuric acid (H SO ) solution. Express the
2 4
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
strength of the solution as milligrams of KOH per millilitre; 1
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. mL of 0.5 N H SO is equivalent to 28.05 mg of KOH.
2 4
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D5350 − 95 (2019)
6.1.2 Increase in Acidity upon Boiling, F—Weigh 10 g of
the sample into the Erlenmeyer flask and boil under the air
condenserwithH SO (1+19)for1 ⁄2horuntilboththeoiland
2 4
water layers are perfectly clear,
...