ASTM D7795 Standard Test Method for Acidity in Ethanol and Ethanol Blends by Titration
1. 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 Test Method A - Developed specifically for measurement of acidity by potentiometric titration. This is the referee method.
1.1.2 Test Method 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
2.1 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
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
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.
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 KHC8H4O4 - KHP-Potassium Acid Phthalate
