1. Chemical Overview
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Name: Diethylhydroxylamine (DEHA)
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CAS No.: 3710-84-7
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Formula: (C₂H₅)₂NOH
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Appearance: Colorless to pale yellow liquid
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Solubility: Miscible with water and most organic solvents
2. Key Performance Characteristics
(1) Oxygen Scavenging (Primary Use)
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Mechanism: Reacts rapidly with dissolved oxygen (O₂) to form harmless byproducts (water, nitrogen, and organic acids).
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Reaction:
(C₂H₅)₂NOH+O₂→H₂O+N₂+Organic Acids
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Advantages:
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Faster than hydrazine (N₂H₄) and safer (non-carcinogenic).
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Works at low temperatures (effective from 25°C to 200°C).
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Lowers corrosion rates in boilers and feedwater systems.
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(2) Metal Passivation
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Forms protective magnetite (Fe₃O₄) layer on steel surfaces, reducing corrosion.
(3) Boiler System Benefits
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Reduces iron/copper deposition in turbines and condensers.
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Minimizes carryover (foaming) due to low volatility.
3. Primary Applications
(1) Boiler Feedwater Treatment
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Dosage: 0.1–2.0 ppm (per ppm of dissolved O₂).
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Replaces hydrazine in modern high-pressure boilers (due to safety regulations).
(2) Industrial Cooling Systems
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Prevents oxygen-induced corrosion in closed-loop cooling systems.
(3) Oil & Gas Industry
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Used in steam flooding (enhanced oil recovery) to protect pipelines.
(4) Power Plants
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Protects steam generators and condensate lines in nuclear/fossil-fuel plants.
4. Advantages Over Alternatives
| Property | DEHA | Hydrazine (N₂H₄) | Sodium Sulfite (Na₂SO₃) |
|---|---|---|---|
| Oxygen Removal Speed | Fast (minutes) | Slow (hours) | Fast (seconds) |
| Toxicity | Low (non-carcinogenic) | High (carcinogenic) | Low |
| Temperature Range | 25–200°C | >100°C (optimal) | <100°C (effective) |
| Byproducts | Non-corrosive | Ammonia (risky) | Sulfate (scaling risk) |
5. Safety & Handling
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Storage: Keep in sealed containers away from oxidizers.
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Handling: Use gloves/goggles (may irritate skin/eyes).
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Environmental Impact:
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Biodegradable; breaks down into water, nitrogen, and CO₂.
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Complies with EPA and REACH regulations.
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6. Typical Formulations
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Often blended with amine-based corrosion inhibitors (e.g., morpholine, cyclohexylamine) for enhanced protection.
DEHA is a highly efficient, safe oxygen scavenger for boiler feedwater and cooling systems, offering fast O₂ removal, low toxicity, and excellent metal passivation. Its replacement of hydrazine in many industries highlights its regulatory and performance advantages.
Recommended for:
✔ High-pressure boilers
✔ Closed-loop cooling systems
✔ Oilfield steam injection
For optimal dosing, conduct dissolved oxygen testing and adjust based on system conditions.