The common product specifications for Benzotriazole (BTA) are designed to ensure its effectiveness as a copper corrosion inhibitor and its suitability for various applications, from industrial water treatment to more sensitive areas like antifreeze and metalworking fluids.
Like other chemicals, BTA is typically available in different grades, primarily Industrial Grade and High-Purity Grade.
1. Industrial Grade BTA
This is the most common form used in industrial water treatment and other general applications. The key specifications focus on purity, physical form, and key impurity limits.
Here is a typical specification table for industrial-grade BTA:
| Specification Parameter | Typical Value / Range | Importance & Reason |
|---|---|---|
| Assay (Purity) | ≥ 98.0% | The primary indicator of active component content. Higher purity generally means better and more consistent performance. |
| Melting Point | 94 – 98 °C | A critical physical property. A sharp melting point within this range confirms the identity and purity of the compound. Values outside this range suggest significant impurities. |
| Appearance | White to light yellow crystalline powder or flakes | A visual check. A pure white color indicates high purity, while a yellow or brown tint can indicate oxidation or the presence of impurities. |
| Moisture Content | ≤ 0.5% | Ensures the product is dry, preventing caking and ensuring accurate dosing. It also reflects good manufacturing and packaging practices. |
| Ash Content | ≤ 0.1% | Indicates the amount of non-combustible inorganic residue. Low ash content suggests minimal catalytic metal impurities that could affect performance. |
| Transmittance | ≥ 90% (at 425nm & 500nm) | A solution color test. A higher transmittance percentage indicates a lighter color and better purity. This is especially important for applications where color matters. |
2. High-Purity / Refined Grade BTA
This grade is used in more demanding applications where color, odor, and ultra-high purity are critical.
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Applications: Automotive and aerospace antifreeze/coolants, metalworking fluids, electroplating baths, and photographic chemicals.
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Key Differentiators:
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Purity: Often ≥ 99.5%.
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Appearance: Almost always pure white crystals.
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Transmittance: Typically ≥ 95% or higher.
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Chloride (Cl⁻) Content: Specified to be very low (e.g., < 10 ppm), as chlorides can be corrosive.
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Heavy Metals: Strict limits on metals like Iron (Fe), Lead (Pb), etc.
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Key Points for Users:
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Physical Form Matters: BTA is typically a solid. Its low solubility in cold water is a key handling characteristic. For easier dosing, the sodium salt (BTA•Na), which is highly water-soluble, is often used.
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Always Request the SDS and Technical Data Sheet (TDS): The manufacturer’s TDS will provide the exact specifications for the product you are purchasing.
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Match the Grade to the Application:
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Use Industrial Grade for standard industrial water treatment (cooling towers, closed loops).
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Use High-Purity Grade for consumer-facing products like antifreeze or in high-tech manufacturing processes.
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In summary, when procuring BTA, the most critical specifications to check are its purity (Assay), melting point, appearance, and moisture content. These parameters collectively ensure you are receiving a high-quality, effective, and stable product.