GLDA·Na₄ (Tetrasodium Glutamate Diacetate) is a biodegradable, non-toxic chelating agent derived from L-glutamic acid. It is widely used in detergents, personal care, oilfield chemicals, and water treatment due to its excellent metal-chelating ability and environmental safety.
Key Temperature Stability Data:
| Condition | Stability Performance | Notes |
|---|---|---|
| Solid Form (Powder) | Stable up to 200°C (392°F) | Decomposes slowly above this temperature. |
| Aqueous Solution | Stable at ≤100°C (212°F) for long-term use | Short-term exposure to 120°C (248°F) is acceptable (e.g., in cleaning applications). |
| High-Temperature Applications (e.g., oilfield scaling inhibition) | Effective at 80–150°C (176–302°F) with some degradation over time | Best used with stabilizers (e.g., pH buffers) in extreme conditions. |
Factors Affecting Thermal Stability
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pH Influence
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Most stable in neutral to alkaline conditions (pH 7–12).
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Acidic environments (pH <4) accelerate degradation.
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Oxygen & Oxidizers
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Exposure to oxidizing agents (e.g., H₂O₂, chlorine) reduces stability at high temperatures.
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Metal Ions
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Forms stable complexes with Ca²⁺, Mg²⁺, Fe³⁺ even at elevated temperatures (useful in boiler/cooling water treatment).
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Comparison with Other Chelators
| Chelating Agent | Max Temp. Resistance (°C/°F) | Biodegradable? |
|---|---|---|
| GLDA·Na₄ | 200°C (392°F) (solid) / 120°C (248°F) (solution) | ✅ Yes |
| EDTA·Na₄ | 150°C (302°F) | ❌ No |
| NTA·Na₃ | 100°C (212°F) | ❌ No |
| HEDP | 200°C (392°F) | ❌ No |
Advantage of GLDA·Na₄: Combines high-temperature resistance with eco-friendliness, making it suitable for green chemistry applications.
Practical Applications & Recommendations
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Detergents & Cleaning Agents
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Safe for hot-water cleaning (up to 80°C).
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Compatible with peroxide-based bleaches if pH >8.
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Oilfield Scale Inhibition
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Effective in wells ≤150°C when combined with polymers (e.g., PPCA).
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Boiler/Cooling Water Treatment
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Use at ≤100°C for long-term stability; higher temps require frequent replenishment.
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Personal Care (Shampoos, Creams)
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Stable under steam sterilization (121°C for 20 min).
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Storage & Handling
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Store solids in a cool, dry place (avoid >40°C/104°F).
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Solutions should be kept at pH 9–11 to prolong shelf life.
Conclusion: GLDA·Na₄ offers moderate to high thermal stability for most industrial applications while maintaining biodegradability. For extreme conditions (e.g., >150°C), consider blending with thermally stable inhibitors like PASP or PESA.