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D1614-09 – Standard Test Method Technical Guide
ASTM D1614-09 (Reapproved 2023) provides a standardized method for determining alkalinity in acetone, reported as ammonia (NH₃). This test is essential for evaluating acetone quality in laboratories and industrial settings.
🔍 Test Method Overview and Procedure
The test method involves taking a specimen of acetone and adding it to a volume of water that has been pre-neutralized to the methyl red indicator endpoint. If the mixture shows alkalinity, it is titrated with 0.05 N sulfuric acid (H₂SO₄) until the endpoint is reached. The alkalinity is then calculated and expressed as weight percent NH₃.
All values observed or calculated must be rounded to the nearest unit in the last right-hand digit, following Practice E29. The standard exclusively uses SI units.
💡 Technical Tip: The methyl red indicator should be prepared fresh monthly by dissolving 0.1 g in 100 mL of methanol, ethanol, or isopropanol to maintain endpoint sensitivity.
⚗️ Reagents and Apparatus
The standard specifies the following equipment and reagents:
| 🔬 Item | 📏 Detailed Specification |
|---|---|
| Buret | 10 mL capacity, with 0.05 mL subdivisions |
| Erlenmeyer Flask | 250 mL capacity |
| Methyl Red Indicator Solution | 1 g/L; dissolve 0.1 g in 100 mL of alcohol solvent |
| Sulfuric Acid (H₂SO₄) | 0.05 N, standardized per Practice E200 |
| Water | Reagent water, Type IV or higher (ASTM D1193) |
All reagents should be ACS reagent grade unless otherwise specified. The water must be of high purity to avoid interference.
📊 Significance and Interpretation of Results
This test method is used for specification acceptance of acetone. The result, expressed as weight percent NH₃, helps determine if the acetone meets required alkalinity limits. Accurate titration and adherence to the procedure are critical for reliable results.
The calculation is based on the volume of H₂SO₄ used, and the result should comply with the rounding requirements of the standard.
⚠️ Safety Warning: Acetone is flammable and may cause irritation. Use in a fume hood and wear appropriate PPE. Consult the SDS for comprehensive safety data.
❓ Frequently Asked Questions
🔍 What was the original approval year of D1614?
Originally approved in 1958, the latest revision was in 2009 and reapproved in 2023.
💡 What is the meaning of alkalinity in this context?
Alkalinity refers to the presence of basic compounds in acetone, calculated as NH₃.
⚡ Can other grades of reagents be used?
Yes, provided they are of sufficient purity to not compromise accuracy.
📌 How is the endpoint detected?
Using methyl red indicator, which changes color at the neutralization point (pH 4.4–6.2).