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D2710-20 – Standard Test Method Technical Guide
🧪 Scope and Applicable Materials
ASTM D2710-20 provides a robust method for determining the Bromine Index of petroleum hydrocarbons, specifically targeting trace amounts of bromine-reactive unsaturates. This test method is strictly applicable to materials with a Bromine Index below 1000 and a distillation end point under 288 °C (550 °F). The standard explicitly applies to essentially olefin-free hydrocarbons or mixtures substantially free from material lighter than isobutane. Typical applicable materials include straight-run and hydrocracked naphtha, reformer feed, kerosine, and aviation turbine fuel.
| 🟦 Parameter | 📏 Specification |
|---|---|
| Bromine Index Range | Below 1000 |
| Distillation End Point | Under 288 °C (550 °F) |
| Material Composition | Essentially olefin-free, free from C₄⁻ |
| Typical Matrices | Naphtha, Kerosine, Aviation Turbine Fuel |
⚠️ Scope Limitation: This method is not suitable for materials with a Bromine Index exceeding 1000 or for industrial aromatic hydrocarbons. For those, refer to Test Method D1159 (Bromine Number) or D1492 / D5776 (Bromine Index of Aromatics) respectively.
⚙️ Test Procedure and Apparatus
The test procedure involves dissolving a known mass of the sample in a specified solvent and titrating it with a standard bromide-bromate solution. The endpoint is detected using a dead stop electrometric titration apparatus. This high-resistance apparatus indicates the endpoint when the presence of free bromine causes a sudden, highly detectable change in the electrical conductivity of the system. Any apparatus capable of performing titrations to pre-set endpoints can be utilized, ensuring flexibility in laboratory equipment while maintaining method integrity.
💡 Analytical Insight: The “dead stop” method is exceptionally sensitive. The sharp inflection in conductivity at the endpoint allows for precise quantification of low levels of unsaturates, making it ideal for trace analysis in reaction solvents.
📊 Significance and Key Technical Data
This test method is critical for assessing the suitability of light petroleum distillates for use as reaction solvents by quantifying trace unsaturates. The Bromine Index, defined as the milligrams of bromine reacting with 100 g of sample, provides a direct benchmark for material quality. Values are reported in SI units (imperial in parentheses). The method is cooperatively tested for the range of 100 to 1000.
| ⚡ Condition | 📏 Standard Method | 🔍 Application Note |
|---|---|---|
| Bromine Index > 1000 | D1159 / IP 130 | Determines Bromine Number instead of Index |
| Industrial Aromatic Hydrocarbons | D1492 (Coulometric) / D5776 (Electrometric) | Subcommittee is examining ways for more consistent endpoint values |
❓ Frequently Asked Questions
🔍 What is the precise definition of Bromine Index?
Per ASTM D2710, the Bromine Index is the number of milligrams of bromine that will react with 100 g of sample under the specific conditions of the test method.
© 2026 TNLab — This article is a technical interpretation for reference only. The original standard as published by ASTM International takes precedence.