ASTM D7795-15

Standard Test Method for Acidity in Ethanol and Ethanol Blends by Titration

SIGNIFICANCE AND USE
5.1 This test method measures acidity in ethanol or ethanol blends quantitatively. Denatured fuel ethanol may contain additives such as corrosion inhibitors and detergents as well as contaminants from manufacturing that can affect the acidity of finished ethanol fuel. Very dilute aqueous solutions of low molecular mass organic acids, such as acetic acid, are highly corrosive to many metals. It is important to keep such acids at a very low level.  
5.2 Acceptable levels of acidity in ethanol or ethanol blends can vary with different specifications but in general it is below 200 mg/kg (ppm). Knowledge of the acidity can be required to establish whether the product quality meets specification.
SCOPE
1.1 This test method covers the determination of acidity as acetic acid (see Specification D4806) in commonly available grades of denatured ethanol, and ethanol blends with gasoline ranging from E95 to E30. This test method is used for determining low levels of acidity, below 200 mg/kg (ppm mass), with the exclusion of carbon dioxide.  
1.1.1 Procedure A—Developed specifically for measurement of acidity by potentiometric titration. This is the referee method.  
1.1.2 Procedure B—Developed specifically for measurement of acidity by color end point titration.  
1.2 The ethanol and ethanol blends may be analyzed directly by this test method without any sample preparation.  
1.3 Review the current and appropriate Material Safety Data Sheets (MSDS) for detailed information concerning toxicity, first aid procedures, and safety precautions and proper personal protective equipments.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 7 on Hazards.

General Information

• Status: Historical
• Publication Date: 14-Dec-2015
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.06 - Analysis of Liquid Fuels and Lubricants

Standards Content (Sample)

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: D7795 − 15
Standard Test Method for
1
Acidity in Ethanol and Ethanol Blends by Titration
This standard is issued under the fixed designation D7795; 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* D4175Terminology Relating to Petroleum Products, Liquid
Fuels, and Lubricants
1.1 This test method covers the determination of acidity as
D4806Specification for Denatured Fuel Ethanol for Blend-
acetic acid (see Specification D4806) in commonly available
ing with Gasolines for Use asAutomotive Spark-Ignition
grades of denatured ethanol, and ethanol blends with gasoline
Engine Fuel
ranging from E95 to E30. This test method is used for
D6708Practice for StatisticalAssessment and Improvement
determining low levels of acidity, below 200mg⁄kg (ppm
of Expected Agreement Between Two Test Methods that
mass), with the exclusion of carbon dioxide.
Purport to Measure the Same Property of a Material
1.1.1 Procedure A—Developed specifically for measure-
E200Practice for Preparation, Standardization, and Storage
ment of acidity by potentiometric titration. This is the referee
of Standard and Reagent Solutions for ChemicalAnalysis
method.
1.1.2 Procedure B—Developed specifically for measure-
3. Terminology
ment of acidity by color end point titration.
3.1 Definitions:
1.2 The ethanol and ethanol blends may be analyzed di-
3.1.1 acidity, n—the quality, state, or degree of being acid.
rectly by this test method without any sample preparation.
D4175
3.1.1.1 Discussion—The amount of acid titrated with a base
1.3 ReviewthecurrentandappropriateMaterialSafetyData
(NaOH or KOH) in a sample of ethanol or ethanol blend with
Sheets (MSDS) for detailed information concerning toxicity,
gasoline, calculated as acetic acid in mg/kg (ppm mass).
firstaidprocedures,andsafetyprecautionsandproperpersonal
protective equipments.
3.2 Abbreviations:
3.2.1 KHC H O —KHP-Potassium Acid Phthalate
1.4 The values stated in SI units are to be regarded as 8 4 4
standard. No other units of measurement are included in this
4. Summary of Test Method
standard.
4.1 Samples are purged with nitrogen prior to and during
1.5 This standard does not purport to address all of the
titrationfortheeliminationofcarbondioxideandthenaknown
safety concerns, if any, associated with its use. It is the
amount of ethanol or ethanol blend sample is analyzed poten-
responsibility of the user of this standard to establish appro-
tiometrically either using a monotonic or dynamic end point
priate safety and health practices and determine the applica-
titrant addition, as specified in Procedure A, or by color end
bility of regulatory limitations prior to use. Some specific
point titration, as specified in Procedure B, using a base
hazards statements are given in Section 7 on Hazards.
(NaOH) solution. Acid content is calculated as milligrams of
acetic acid per kilogram of sample.
2. Referenced Documents
2 5. Significance and Use
2.1 ASTM Standards:
D770Specification for Isopropyl Alcohol 5.1 This test method measures acidity in ethanol or ethanol
D1193Specification for Reagent Water blends quantitatively. Denatured fuel ethanol may contain
additives such as corrosion inhibitors and detergents as well as
contaminants from manufacturing that can affect the acidity of
finished ethanol fuel. Very dilute aqueous solutions of low
1
This test method is under the jurisdiction of ASTM Committee D02 on
molecular mass organic acids, such as acetic acid, are highly
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.06 on Analysis of Liquid Fuels and Lubricants.
corrosive to many metals. It is important to keep such acids at
Current edition approved Dec. 15, 2015. Published February 2016. Originally
a very low level.
approved in 2012. Last previous edition approved in 2012 as D7795–12. DOI:
10.1520/D7795-15.
5.2 Acceptablelevelsofacidityinethanolorethanolblends
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
can vary with different specifications but in general it is below
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
200mg/kg(ppm).Knowledgeoftheaciditycanberequiredto
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. establish whether the product quality meets specification.
*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
1

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D7795 − 15
6. Interferences
...

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: D7795 − 12 D7795 − 15
Standard Test Method for
1
Acidity in Ethanol and Ethanol Blends by Titration
This standard is issued under the fixed designation D7795; 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 Scope*
1.1 This test method covers the determination of acidity as acetic acid (see Specification D4806) in commonly available grades
of denatured ethanol, and ethanol blends with gasoline ranging from E95 to E30. This test method is used for determining low
levels of acidity, below 200200 mg ⁄ mg/kg kg (ppm mass), with the exclusion of carbon dioxide.
1.1.1 Test Method Procedure A—Developed specifically for measurement of acidity by potentiometric titration. This is the
referee method.
1.1.2 Test Method Procedure B—Developed specifically for measurement of acidity by color end point titration.
1.2 The ethanol and ethanol blends may be analyzed directly by this test method without any sample preparation.
1.3 Review the current and appropriate Material Safety Data Sheets (MSDS) for detailed information concerning toxicity, first
aid procedures, and safety precautions and proper personal protective equipments.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 and health practices and determine the applicability of regulatory
limitations prior to use. Some specific hazards statements are given in Section 7 on Hazards.
2. Referenced Documents
2
2.1 ASTM Standards:
D770 Specification for Isopropyl Alcohol
D1193 Specification for Reagent Water
D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants
D4806 Specification for Denatured Fuel Ethanol for Blending with Gasolines for Use as Automotive Spark-Ignition Engine Fuel
D6300D6708 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and
LubricantsStatistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to
Measure the Same Property of a Material
E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
3. Terminology
3.1 Definitions:
3.1.1 acidity, n—the quality, state, or degree of being acid. D4175
1
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 Dec. 1, 2012Dec. 15, 2015. Published February 2013February 2016. Originally approved in 2012. Last previous edition approved in 2012 as
D7795 – 12. DOI: 10.1520/D7795-12.10.1520/D7795-15.
2
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.
3.1.1.1 Discussion—
The amount of acid titrated with a base (NaOH or KOH) in a sample of ethanol or ethanol blend with gasoline, calculated as acetic
acid in mg/kg (ppm mass).
3.2 Abbreviations:
3.2.1 KHC H O —KHP-Potassium Acid Phthalate
8 4 4
*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
1

---------------------- Page: 1 ----------------------
D7795 − 15
4. Summary of Test Method
4.1 Samples are purged with nitrogen prior to and during titration for the elimination of carbon dioxide and then a known
amount of ethanol or ethanol blend sample is analyzed potentiometrically either using a monotonic or dynamic end point titrant
addition, as specified in Test Method Procedure A, or by color end point titration, as specified in Test Method Procedure B, using
a base (NaOH) solution. Acid content is calculated as milligrams of acetic acid per kilogram of sample.
5. Significance and Use
5.1 This test method measures acidity in ethanol or ethanol blends quantitatively. Denatured fuel ethanol may contain additives
such as corrosion inhibitors and dete
...