ASTM D1093-23

Standard Test Method for Acidity of Hydrocarbon Liquids and Their Distillation Residues

SIGNIFICANCE AND USE
5.1 Some petroleum products are treated with mineral acid as part of the refining procedure. Obviously, any residual mineral acid in a petroleum product is undesirable. The absence of a positive indication in the test for acidity of the distillation residue or aqueous extract of a hydrocarbon liquid is an assurance of the care used in refining the fuel or solvent.
SCOPE
1.1 This test method covers the qualitative determination of the acidity of hydrocarbon liquids and their distillation residues. (Warning—Many hydrocarbon liquids are extremely flammable. Harmful if inhaled. Hydrocarbon liquid vapors can cause a flash fire.)  
1.2 If desired to determine the basicity of a hydrocarbon liquid, proceed in accordance with 9.2 or 9.3, but substitute 3 drops of phenolphthalein indicator solution for the methyl orange indicator. A pink or red color in the aqueous solution when phenolphthalein is used indicates basicity.  
1.3 The results obtained by this test method are qualitative expressions. However, for the preparation of reagents and in the procedure, acceptable SI units are to be regarded as the standard.  
1.4 This standard does not purport to address all of the safety problems, 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.

General Information

• Status: Published
• Publication Date: 30-Jun-2023
• ICS: 75.080 - Petroleum products in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.06 - Analysis of Liquid Fuels and Lubricants

Relations

• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D86-23a - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D86-23ae1 - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D91-02(2017) - Standard Test Method for Precipitation Number of Lubricating Oils
• Effective Date: 01-Jul-2017
• Refers: ASTM D86-16 - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Jul-2016
• Refers: ASTM D91-02(2012) - Standard Test Method for Precipitation Number of Lubricating Oils
• Effective Date: 01-Nov-2012
• Refers: ASTM D91-02(2012)e1 - Standard Test Method for Precipitation Number of Lubricating Oils
• Effective Date: 01-Nov-2012
• Refers: ASTM D86-11b - Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure
• Effective Date: 01-Dec-2011
• Refers: ASTM D1078-11 - Standard Test Method for Distillation Range of Volatile Organic Liquids
• Effective Date: 15-Nov-2011
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D86-09 - Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure
• Effective Date: 15-Apr-2009
• Refers: ASTM D86-08a - Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure
• Effective Date: 15-Dec-2008
• Refers: ASTM D86-08 - Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure
• Effective Date: 15-Nov-2008
• Refers: ASTM D850-03(2008)e1 - Standard Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials
• Effective Date: 01-Jun-2008

Overview

ASTM D1093-23 is the internationally recognized standard test method for the qualitative determination of the acidity of hydrocarbon liquids and their distillation residues. Published by ASTM International, this standard is crucial for the petroleum and petrochemical industries, ensuring the quality and safety of fuels, solvents, and related products. The method provides an important quality control check, confirming the absence of undesirable residual mineral acids-a result of certain refining processes-by detecting acidic properties in hydrocarbon samples or their residues.

Key Topics

• Qualitative Acidity Testing
  ASTM D1093-23 outlines a procedure for identifying whether hydrocarbon liquids or their distillation residues exhibit acidic characteristics. The method uses a methyl orange indicator to detect the presence of acid in an aqueous extract.

• Detection of Basicity
  The method offers an option to determine basicity by using phenolphthalein indicator, which indicates alkalinity in the tested sample.

• Safety Considerations
  Hydrocarbon liquids are often highly flammable and harmful if inhaled. Proper laboratory safety, health, and environmental practices must be observed when conducting the test.

• Scope and Limitations
  The procedure provides qualitative-not quantitative-results, serving as a pass/fail indicator rather than a direct measurement of acid content.

• Standardization and SI Units
  The preparation of reagents and procedures must adhere to SI units and internationally accepted practices in line with WTO TBT Committee principles.

Applications

• Quality Control in Refining
  The absence of acidity in hydrocarbon liquids and their residues verifies the effectiveness of purification steps utilized in oil refining and petrochemical production, ensuring that no residual mineral acid remains that could corrode equipment or impair fuel performance.

• Fuel and Solvent Assessment
  Fuel producers and solvent manufacturers use this method to confirm the quality and reliability of products before distribution, reducing the risk of equipment damage and adverse chemical reactions during storage or use.

• Regulatory Compliance
  Compliance with ASTM D1093-23 supports adherence to regulatory requirements for petroleum products, demonstrating due diligence and robust process control to auditors, clients, and government authorities.

• Sampling Procedures
  The standard provides guidance for both manual and automatic sampling methods, ensuring that the tested sample is representative of the batch.

Related Standards

• ASTM D86: Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• ASTM D91: Test Method for Precipitation Number of Lubricating Oils
• ASTM D850: Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials
• ASTM D1078: Test Method for Distillation Range of Volatile Organic Liquids
• ASTM D4057: Practice for Manual Sampling of Petroleum and Petroleum Products
• ASTM D4177: Practice for Automatic Sampling of Petroleum and Petroleum Products
• ASTM D1193: Specification for Reagent Water
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants

Practical Value

Implementing ASTM D1093-23 in quality assurance routines safeguards the integrity of fuels, lubricants, and solvents, ensuring they are free from acidic impurities that can result from incomplete removal of refining agents. This improves equipment reliability, product safety, and customer satisfaction across petroleum and chemical industries, and demonstrates a commitment to internationally recognized quality standards.

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: D1093 − 23
Standard Test Method for
Acidity of Hydrocarbon Liquids and Their Distillation
Residues
This standard is issued under the fixed designation D1093; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* Liquid Fuels at Atmospheric Pressure
D91 Test Method for Precipitation Number of Lubricating
1.1 This test method covers the qualitative determination of
Oils
the acidity of hydrocarbon liquids and their distillation resi-
D850 Test Method for Distillation of Industrial Aromatic
dues. (Warning—Many hydrocarbon liquids are extremely
Hydrocarbons and Related Materials
flammable. Harmful if inhaled. Hydrocarbon liquid vapors can
D1078 Test Method for Distillation Range of Volatile Or-
cause a flash fire.)
ganic Liquids
1.2 If desired to determine the basicity of a hydrocarbon
D1193 Specification for Reagent Water
liquid, proceed in accordance with 9.2 or 9.3, but substitute 3
D4057 Practice for Manual Sampling of Petroleum and
drops of phenolphthalein indicator solution for the methyl
Petroleum Products
orange indicator. A pink or red color in the aqueous solution
D4175 Terminology Relating to Petroleum Products, Liquid
when phenolphthalein is used indicates basicity.
Fuels, and Lubricants
1.3 The results obtained by this test method are qualitative D4177 Practice for Automatic Sampling of Petroleum and
Petroleum Products
expressions. However, for the preparation of reagents and in
the procedure, acceptable SI units are to be regarded as the
3. Terminology
standard.
3.1 Definitions:
1.4 This standard does not purport to address all of the
3.1.1 For definitions of terms used in this test method, refer
safety problems, if any, associated with its use. It is the
to Terminology D4175.
responsibility of the user of this standard to establish appro-
3.2 Definitions of Terms Specific to This Standard:
priate safety, health, and environmental practices and deter-
3.2.1 acidity, n—the quality, state or degree of being acid.
mine the applicability of regulatory limitations prior to use.
3.2.1.1 Discussion—In this test method, the criterion for
1.5 This international standard was developed in accor-
acidity is a pink or red color when methyl orange indicator is
dance with internationally recognized principles on standard-
used.
ization established in the Decision on Principles for the
3.2.2 basicity, n—the quality, state or degree of being basic.
Development of International Standards, Guides and Recom-
3.2.2.1 Discussion—In this test method, the criterion for
mendations issued by the World Trade Organization Technical
basicity is a pink or red color when phenolphthalein indicator
Barriers to Trade (TBT) Committee.
is used.
2. Referenced Documents
3.2.3 distillation residue, n—that portion of the sample
remaining after distillation using specified procedures.
2.1 ASTM Standards:
D86 Test Method for Distillation of Petroleum Products and
4. Summary of Test Method
4.1 The sample of distillation residue or hydrocarbon liquid
1 is shaken with water and the aqueous layer tested for acidity to
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of methyl orange indicator.
Subcommittee D02.06 on Analysis of Liquid Fuels and Lubricants.
4.2 The aqueous layer can also be tested for basicity using
Current edition approved July 1, 2023. Published July 2023. Originally approved
in 1950. Last previous edition approved in 2017 as D1093 – 11 (2017). DOI: phenolphthalein indicator.
10.1520/D1093-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 5. Significance and Use
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.1 Some petroleum products are treated with mineral acid
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. as part of the refining procedure. Obviously, any residual
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1093 − 23
mineral acid in a petroleum product is undesirable. The 9. Procedure
absence of a positive indication in the test for acidity of the
9.1 All distillation flasks and glassware used in this test
distillation residue or aqueous extract of a hydrocarbon liquid
shall be clean and dry There shall be no contaminant present
is an assurance of the care used in refining the fuel or solvent.
that could affect the acidic or basic nature of the material under
test.
6. Apparatus
9.2 Distillation Residue—After measuring the percent resi-
6.1 Centrifuge Tube, cone-shaped, 100 mL capacity; cali-
due collected from the distillation by Test Method D86, Test
bration not necessary.
Method D850, or Test Method D1078 as required, extract the
residue with water as described below. Use either the graduated
6.2 Centrifuge, capable of swinging two centrifuge tubes at
cylinder containing the residue from the distillation procedure
1500 r ⁄min.
directly or another appropriately sized container, such as a test
NOTE 1—Apparatus 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: D1093 − 11 (Reapproved 2017) D1093 − 23
Standard Test Method for
Acidity of Hydrocarbon Liquids and Their Distillation
Residues
This standard is issued under the fixed designation D1093; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
1.1 This test method covers the qualitative determination of the acidity of hydrocarbon liquids and their distillation residues.
(Warning—Many hydrocarbon liquids are extremely flammable. Harmful if inhaled. Hydrocarbon liquid vapors can cause a flash
fire.)
1.2 If desired to determine the basicity of a hydrocarbon liquid, proceed in accordance with 9.2 or 9.3, but substitute 3 drops of
phenolphthalein indicator solution for the methyl orange indicator. A pink or red color in the aqueous solution when
phenolphthalein is used indicates basicity.
1.3 The results obtained by this test method are qualitative expressions. However, for the preparation of reagents and in the
procedure, acceptable SI units are to be regarded as the standard.
1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and healthsafety, 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.
2. Referenced Documents
2.1 ASTM Standards:
D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
D91 Test Method for Precipitation Number of Lubricating Oils
D850 Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials
D1078 Test Method for Distillation Range of Volatile Organic Liquids
D1193 Specification for Reagent Water
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.06 on Analysis of Liquid Fuels and Lubricants.
Current edition approved May 1, 2017July 1, 2023. Published June 2017July 2023. Originally approved in 1950. Last previous edition approved in 20112017 as
D1093 – 11.D1093 – 11 (2017). DOI: 10.1520/D1093-11R17.10.1520/D1093-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1093 − 23
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
3.2 Definitions:Definitions of Terms Specific to This Standard:
3.2.1 acidity, n—the quality, state or degree of being acid.
3.2.1.1 Discussion—
In this test method, the criterion for acidity is a pink or red color when methyl orange indicator is used.
3.2.2 basicity, n—the quality, state or degree of being basic.
3.2.2.1 Discussion—
In this test method, the criterion for basicity is a pink or red color when phenolphthalein indicator is used.
3.2.3 distillation residue, n—that portion of the sample remaining after distillation using specified procedures.
4. Summary of Test Method
4.1 The sample of distillation residue or hydrocarbon liquid is shaken with water and the aqueous layer tested for acidity to methyl
orange indicator.
4.2 The aqueous layer can also be tested for basicity using phenolphthalein indicator.
5. Significance and Use
5.1 Some petroleum products are treated with mineral acid as part of the refining procedure. Obviously, any residual mineral acid
in a petroleum product is undesirable. The absence of a positive indication in the test for acidity of the distillation residue or
aqueous extract of a hydrocarbon liquid is an assurance of the care used in refining the fuel or solvent.
6. Apparatus
6.1 Centrifuge Tube, cone-shaped, 100 mL capacity; calibration not necessary.
6.2 Centrifuge, capable of swinging two centrifuge tubes at 1500 r ⁄min.
NOTE 1—Apparatus used for Test Method D91 is satisfactory.
7. Reagents
7.1 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
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.
7.1.1 Comme
...