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D611-23 – Standard Test Method Technical Guide
📚 Overview and Scope
ASTM D611-23, originally approved in 1941, provides standard test methods for determining the aniline point and mixed aniline point of petroleum products and hydrocarbon solvents. The aniline point is defined as the minimum equilibrium solution temperature for equal volumes of aniline and sample. The standard covers five test methods: Test Method A for transparent samples with an initial boiling point above room temperature and where the aniline point is below the bubble point and above the solidification point of the mixture; Test Method B, a thin-film method for dark samples; Test Methods C and D for samples that may vaporize appreciably at the aniline point, with Test Method D particularly suitable for small quantities; and Test Method E using an automatic apparatus for the range covered by Methods A and B. Additionally, the mixed aniline point is determined for samples with aniline points below the temperature at which aniline crystallizes from the mixture. All values are in SI units. The standard includes a warning about mercury hazards and emphasizes user responsibility for safety practices.
⚙️ Test Methods and Procedures
Each test method is designed for specific sample characteristics. Selection depends on transparency, volatility, and sample availability. All methods require careful control of temperature to ensure accurate determination of the aniline point.
| 🔍 Method | 📏 Description | 🎯 Suitable For |
|---|---|---|
| A | Standard method using equal volumes of aniline and sample | Transparent samples with initial boiling point above room temperature; aniline point below bubble point and above solidification point |
| B | Thin-film method | Samples too dark for testing by Method A |
| C and D | Methods for volatile samples with precautions against vaporization | Samples that may vaporize appreciably at the aniline point; Method D for small quantities |
| E | Automatic apparatus procedure | Range covered by Methods A and B |
📊 Key Terminology and Referenced Standards
Essential terms are defined in Terminology D4175, with the aniline point being the primary parameter. The following referenced standards are integral for equipment and ancillary testing:
| 🟦 Standard | 📜 Title |
|---|---|
| D1500 | Test Method for ASTM Color of Petroleum Products (ASTM Color Scale) |
| D4175 | Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants |
| E1 | Specification for ASTM Liquid-in-Glass Thermometers |
⚠️ Mercury Warning: Mercury is designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Use caution when handling mercury and mercury-containing products. Consult the applicable Safety Data Sheet (SDS) for additional information. Sales may be prohibited by local or national law.
💡 Method Selection Tip: For transparent samples, use Test Method A. For dark samples, employ Test Method B. If sample volatility is a concern, choose Test Method C or D. Test Method D is particularly suited for limited sample quantities.
❓ Frequently Asked Questions
🔍 What is the definition of aniline point?
The aniline point is the minimum equilibrium solution temperature for equal volumes of aniline and sample.
💡 Which test method should be used for dark petroleum products?
Test Method B, the thin-film method, is suitable for samples too dark for testing by Test Method A.
⚡ What are the key safety concerns in this standard?
The standard warns about mercury hazards and recommends consulting the SDS for safe handling practices.
📌 How is the mixed aniline point determined?
The mixed aniline point is determined for petroleum products and hydrocarbon solvents that have aniline points below the temperature at which aniline crystallizes from the aniline-sample mixture.