Sodium Butyl Benzotriazole (BBT.Na) is a copper corrosion inhibitor used in cooling tower water treatment. It’s part of the benzotriazole family, which is known for protecting yellow metals (like copper and brass) from corrosion, especially in mixed-metal systems.
What Is Sodium Butyl Benzotriazole?
Why Use Sodium Butyl Benzotriazole?
- Chemical class: A benzotriazole derivative, modified with a butyl group to enhance performance
- Copper & Brass Corrosion Protection
- Adsorbs onto the surface of copper alloys, forming a thin, invisible molecular film
- This film acts as a barrier to oxygen, chlorides, and other corrosive agents
- Reduces the risk of:
- Pitting
- Galvanic corrosion between copper and steel
- Stability in Harsh Conditions
- More stable than traditional benzotriazole (BZT) in:
- Oxidizing environments
- High-chloride or high-TDS water
- Alkaline pH ranges (7–9+)
- Synergy With Other Inhibitors
- Often combined with:
- PBTC or phosphonates (for steel corrosion)
- Polyacrylates (for dispersion)
- Zinc or molybdate
- Compatible with oxidizing biocides, though higher biocide levels may degrade the protective film over time
| Parameter | Value / Range |
| Target dosage | 1–5 ppm active BBT |
| pH stability | Effective between 6.5–9.5 |
| Metal protection | Primarily copper/brass |
| Solubility | High (due to sodium salt form) |
- Stronger film and longer protection than regular BZT or TTA
- Works in reclaim/reuse and high-chloride waters
- Reduces risk of galvanic corrosion in mixed metal systems (copper + steel)
- Minimizes copper leaching into discharge — helps meet discharge permit limits