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D2073-92 – Standard Test Method Technical Guide
🧪 Significance and Scope of D2073-92
ASTM D2073-92, jointly developed by ASTM and the American Oil Chemists’ Society (AOCS), provides referee test methods for the potentiometric determination of amine values in fatty amines, diamines, and amidoamines. These values are critical for characterizing the purity and reactivity of these materials used in coatings, surfactants, and chemical intermediates.
The standard covers the determination of total, primary, secondary, and tertiary amine values in fatty amines and diamines. For fatty amidoamines, only the total amine value is applicable per the scope limitations of the standard.
⚠️ Scope Limitation: Test methods for primary, secondary, and tertiary amine values are not applicable to fatty amidoamines. Users should carefully select the appropriate methodology based on the sample matrix.
📏 Key Terminology and Definitions
The standard defines amine values as the number of milligrams of potassium hydroxide (KOH) equivalent to the basicity found in one gram of specimen. These values are fundamental for quality control and material specification.
| 🟦 Term | 📐 Definition (mg KOH/g) |
|---|---|
| Total Amine Value | Basicity in 1 g of specimen |
| Primary Amine Value | Primary amine basicity in 1 g of specimen |
| Secondary Amine Value | Secondary amine basicity in 1 g of specimen |
| Tertiary Amine Value | Tertiary amine basicity in 1 g of specimen |
⚙️ Essential Apparatus and Reagents
Execution of the referee potentiometric method requires specific laboratory equipment and high-purity reagents to ensure accuracy and reproducibility consistent with a referee method.
| ⚡ Apparatus | 🎯 Specification Requirement |
|---|---|
| Air Condenser | Minimum length of 650 mm |
| Erlenmeyer Flask | 250 mL capacity, wide-mouth, borosilicate glass, alkali-resistant |
| pH Meter | Glass electrode, conforming to Test Method E 70 |
| Microburet | 10 mL capacity, graduated to 0.02 mL |
| Magnetic Stirrer | Inert plastic-coated stirring bar |
Key reagents include reagent grade chemicals conforming to ACS specifications, and reagent water conforming to Type II of Specification D 1193. Glacial acetic acid (CH₃COOH) is a critical non-aqueous solvent for the potentiometric titration.
🚨 Safety Hazard: Glacial acetic acid is corrosive and flammable. Specific hazard warnings are detailed in Notes 1 and 6.1 of the standard. Appropriate engineering controls and personal protective equipment must be used.
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D2073-92?
D2073-92 provides referee potentiometric test methods for determining the total, primary, secondary, and tertiary amine values of fatty amines, diamines, and the total amine value of fatty amidoamines. It is used for quality assurance and raw material characterization.
💡 How are amine values calculated in this standard?
Amine values are expressed as the number of milligrams of potassium hydroxide (KOH) equivalent to the basicity present in one gram of the specimen. The potentiometric titration differentiates the titration curve inflections to quantify the different amine types.
⚡ Can these test methods be applied to fatty amidoamines?
No. While the total amine value test method is applicable to fatty amidoamines, the individual test methods for primary, secondary, and tertiary amine values are explicitly noted as not applicable to fatty amidoamines per Section 1.1 of the scope.
📌 What type of water and reagents are required?
The standard requires reagent grade chemicals conforming to the specifications of the American Chemical Society. Water used must conform to Type II of ASTM Specification D1193 for Reagent Water to avoid contamination and ensure consistent titration results.