ASTM D6423 Determination of pHe of Ethanol, Denatured Fuel Ethanol, and Fuel Ethanol (Ed75-Ed85)
1. Scope
1.1 This test method covers a procedure to determine a measure of the acid strength of high ethanol content fuels. These include ethanol, denatured fuel ethanol, and fuel ethanol (Ed75-Ed85). The test method is applicable to fuels containing nominally 70 volume % ethanol, or higher, as described in Specifications D4806 and D5798.
1.2 Acid strength as measured in this test method is defined as pHe. A pHe value for alcohol solutions is not directly comparable to pH values of water solutions.
1.3 The value of pHe will depend somewhat on the fuel blend, the stirring rate, and the time the electrode is in the fuel.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
D4806 Specification for Denatured Fuel Ethanol for Blending with Gasolines for Use as Automotive Spark-Ignition Engine Fuel
D5798 Specification for Fuel Ethanol (Ed75-Ed85) for Automotive Spark-Ignition Engines
3. Terminology
3.1 Definitions:
3.1.1 ethanol, n - ethyl alcohol, the chemical compound, C2H5OH.
3.1.2 denaturants, n - natural gasoline, gasoline components, unleaded gasoline, or toxic or noxious materials added to fuel ethanol to make it unsuitable for beverage use but not unsuitable for automotive fuel use.
3.1.3 denatured fuel ethanol, n - fuel ethanol made unfit for beverage use by the addition of denaturants.
3.1.4 fuel ethanol (Ed75-Ed85), n - a blend of ethanol and hydrocarbons of which the ethanol portion is nominally 75 to 85 volume % denatured ethanol.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 pHe, n - a measure of the acid strength of alcohol fuels defined by this apparatus and procedure.
