Chelating agent Glutamic Acid, N,N-diacetic Acid, Tetrasodium Salt (GLDA-Na4)

Glutamic acid, N,N-diacetic acid, tetrasodium salt (GLDA-Na4) is an advanced, high-performance, bio-based chelating agent. Derived primarily from natural, renewable raw materials (typically fermentation-derived L-glutamic acid), GLDA-Na4 serves as a premier “green” alternative to legacy phosphonates and synthetic aminopolycarboxylates like EDTA and NTA.

It stands out in the industry for having an incredibly high solubility profile, excellent performance across a wide pH range, and a highly favorable environmental footprint.

1. Chemical Profile & Molecular Nature

GLDA-Na4 belongs to the aminopolycarboxylate family. Its structural backbone features a central nitrogen atom bound to multiple carboxylic groups, creating a flexible arrangement capable of wrapping securely around polyvalent metal ions.

Chemical Formula: $\text{C}_9\text{H}_9\text{NO}_8\text{Na}_4$
CAS Number: 51981-21-6
Molecular Weight: $\approx 351.1 \text{ g/mol}$
Bio-based Carbon Content: Typically greater than 85% of its organic carbon is derived from renewable vegetable sources.
Environmental Degradation: Readily biodegradable (>60% mineralized within 28 days under OECD 301B tests). It does not persist in the environment or bioaccumulate in food chains.

2. Key Characteristics & Performance Traits

Extreme Solubility and High Concentration Stability

One of GLDA-Na4’s defining technical advantages is its extraordinary solubility in water. Unlike EDTA, which can be difficult to dissolve at high concentrations or low temperatures, GLDA-Na4 can be formulated into highly concentrated, stable aqueous solutions (up to 50% active matter) across a broad temperature range.

High Calcium Complexing Power over Wide pH

GLDA-Na4 exhibits strong complexing constants for hard-water ions ( $\text{Ca}^{2+}$ , $\text{Mg}^{2+}$ ) and transition metals ( $\text{Fe}^{3+}$ , $\text{Cu}^{2+}$ , $\text{Mn}^{2+}$ ). Notably, its binding efficiency for calcium remains exceptionally high even under strongly acidic conditions (pH 2–4) up to highly alkaline environments (pH 12–13).

Exceptional Synergy with Biocides and Surfactants

In cleaning and disinfecting formulations, GLDA-Na4 weakens the outer cell membranes of bacteria by sequestering the calcium and magnesium ions that structurally stabilize them. This makes it a highly effective booster for biocides and preservatives, often allowing formulators to lower the concentration of harsher active ingredients.

Peroxide Stability & Catalytic Protection

GLDA-Na4 is highly stable in the presence of strong oxidizing agents such as hydrogen peroxide ( $\text{H}_2\text{O}_2$ ) and peracetic acid. By binding trace iron or copper contaminants, it prevents the homolytic cleavage of the peroxide bonds, protecting the bleach bath from rapid, wasteful decomposition.

3. Core Industrial Applications

Industrial & Institutional (I&I) Cleaning: Widely used in automatic dishwashing detergents, liquid laundry concentrates, and vehicle wash systems. It replaces EDTA to prevent film formation and water-spotting.
Textile Wet Processing: Applied in the desizing, scouring, and bleaching phases of natural fibers. It effectively controls metal ions from process water or raw crop debris, protecting fabrics from localized peroxide pinhole damage and ensuring uniform dye uptake.
Oilfield and Industrial Descaling: Used as a highly effective descaling agent to dissolve calcium carbonate ( $\text{CaCO}_3$ ) and sulfate scales in downhole operations or heat exchangers, particularly because it functions safely without corroding delicate metal alloys.
Personal Care & Cosmetics: Acts as a sustainable stabilizer in soaps, shampoos, and lotions to prevent rancidity, discoloration, and precipitation caused by trace metals.

4. Technical Comparison: GLDA-Na4 vs. Competitors

Metric	GLDA-Na4	IDS-Na4	EDTA-Na4
Primary Raw Material	Bio-based (L-Glutamate)	Synthetic (Maleic/Aspartic)	Synthetic (Petrochemical)
Max Formulation Solubility	Extremely High (~50%)	Moderate-High	Low-Moderate (~30%)
Acidic Stability (pH 2-5)	Excellent	Moderate	Poor (Precipitates as free acid)
Alkaline Stability (pH 10-13)	Excellent	Excellent	Excellent
Biodegradability	Ready (>60% in 28d)	Ready (>75% in 28d)	Poor / Non-biodegradable