What is DEHA?

DEHA (Diethylhydroxylamine) is an organic compound with the chemical formula (C₂H₅)₂NOH. It is widely used as an oxygen scavenger, corrosion inhibitor, and reducing agent in industrial applications, particularly in water treatment and boiler systems. Below is a detailed breakdown of its properties, uses, and safety considerations:

1. Key Properties of DEHA

Property Description

Chemical Formula (C₂H₅)₂NOH

Molecular Weight 89.14 g/mol

Appearance Colorless to pale yellow liquid

Odor Ammonia-like

Solubility Miscible with water and most organic solvents

Boiling Point ~125–130°C

Density ~0.867 g/cm³ (at 20°C)

pH (1% solution) ~10–11 (alkaline)

2. Primary Applications

(1) Water Treatment (Major Use)

Oxygen Scavenger:

Reacts rapidly with dissolved oxygen (O₂) in boiler feedwater to prevent corrosion:

(Further decomposes)

Advantages over hydrazine (N₂H₄):

Less toxic (non-carcinogenic).

Faster reaction at low temperatures (effective even <100°C).

Metal Passivation:

Forms protective films on iron/copper surfaces, reducing corrosion rates.

(2) Industrial Processes

Polymerization Inhibitor: Prevents unwanted radical reactions in plastics (e.g., PVC production).

Photographic Developer: Used in some photographic solutions as a reducing agent.

(3) Other Uses

Fuel Additive: Stabilizes fuels by preventing oxidation.

Cosmetics/Pharma: Rarely used as a stabilizer in formulations (strict purity required).

3. Technical Advantages

High Efficiency: 1 kg DEHA removes ~0.5 kg O₂ (similar to hydrazine).

Thermal Stability: Effective in boiler systems up to 300°C.

Low Sludging: Unlike sulfite-based scavengers, it produces minimal solids.

Compatibility: Works well with amine-based corrosion inhibitors (e.g., morpholine).

4. Safety & Handling

Parameter Details

Toxicity (LD50) ~1,500–2,000 mg/kg (rat, oral) – moderately hazardous

Storage Keep in sealed containers, away from oxidizers and acids (risk of exothermic reactions).

Exposure Limits OSHA PEL: Not established; handle with ventilation (vapors irritate eyes/lungs).

Environmental Biodegradable (~60% in 28 days), but high COD – treat wastewater before discharge.

5. Comparison with Alternatives

Feature DEHA Hydrazine (N₂H₄) Sodium Sulfite (Na₂SO₃)

Toxicity Low High (carcinogenic) Low

Reaction Speed Fast (even <100°C) Slow (needs >100°C) Fast

Byproducts Non-scaling Ammonia (NH₃) Sulfate (SO₄²⁻) sludge

Cost Moderate High Low

6. Where to Buy

Industrial Suppliers:

BASF, Arkema, Nouryon (formerly AkzoNobel).

Chinese manufacturers (e.g., Jiangsu World Chemical).

Grades Available:

Technical grade (90–95%) for water treatment.

High-purity (>99%) for pharmaceuticals.

Conclusion

DEHA is a safer, efficient alternative to hydrazine for oxygen control in boilers and industrial systems. Its low toxicity, fast action, and compatibility make it ideal for modern water treatment, though cost may be higher than sulfite-based options. Always conduct a compatibility test before full-scale use.

For specific dosing guidelines, consult water chemistry experts based on your system’s O₂ levels and metallurgy (e.g., carbon steel vs. copper alloys).