Disodium EDTA (EDTA-2Na) and Tetrasodium EDTA (EDTA-4Na) are both EDTA salts used as chelating agents, but they differ significantly in pH, solubility, and optimal applications. EDTA-2Na is mildly acidic (pH 4–5) and is preferred for cosmetics, personal care, food, and pharmaceutical formulations. EDTA-4Na is strongly alkaline (pH 10.5–11.5) and is better suited for industrial cleaning, water treatment, and textile processing. Choosing the right salt depends on formulation pH, solubility requirements, and application.
What Is Disodium EDTA?
Disodium EDTA is the disodium salt of ethylenediaminetetraacetic acid (EDTA), commonly supplied as a white crystalline powder with CAS number 6381-92-6. It contains two sodium ions and functions primarily as a chelating agent that binds metal ions such as calcium, magnesium, iron, and copper.
The compound is also known as EDTA-2Na, disodium edetate, or EDTA disodium salt. The common commercial form is Disodium EDTA dihydrate, with a molecular formula of C₁₀H₁₄N₂Na₂O₈·2H₂O and a molecular weight of approximately 372.24 g/mol.
Unlike free EDTA acid, which contains no sodium ions, this salt form contains two sodium ions. This changes its physical and formulation properties and makes it more useful in aqueous formulations. However, the main function remains the same: chelating metal ions.
Other common names for this compound include:
- EDTA-2Na
- EDTA disodium salt
- Disodium edetate
- EDTA-Na₂
- Na₂EDTA
- Disodium EDTA dihydrate
What Are the Chemical Properties and Specifications of Disodium EDTA?
Disodium EDTA dihydrate has a CAS number of 6381-92-6, a molecular weight of 372.24 g/mol, and a typical purity of ≥99%. It appears as a white crystalline powder, with a 1% solution pH of 4.0–5.0 and a chelate value of 260–290.
The chemical properties of this compound determine how it performs in industrial formulations. Below are the key specifications that buyers should evaluate when sourcing this product:
| Property | Disodium EDTA Dihydrate Specification |
|---|---|
| Common name | Disodium EDTA |
| Chemical name | Disodium ethylenediaminetetraacetate dihydrate |
| Other names | EDTA-2Na, Disodium Edetate, EDTA Disodium Salt |
| CAS No. | 6381-92-6 |
| Molecular formula | C₁₀H₁₄N₂Na₂O₈·2H₂O |
| Molecular weight | Approximately 372.24 g/mol |
| Appearance | White crystalline powder |
| Typical assay | ≥99.0% |
| pH (1% solution) | 4.0–5.0 |
| Chelate value | 260–290 |
| Chloride (Cl) | ≤0.01% |
| Sulfate (SO₄) | ≤0.05% |
| Iron (Fe) | ≤0.001% |
| Heavy metals (Pb) | ≤0.001% |
When purchasing Disodium EDTA, buyers should confirm the exact hydrate form because molecular weight and specifications can differ between EDTA salt forms. The powder form makes the compound suitable for dry blending, powder formulations, aqueous solution preparation, chemical manufacturing, laboratory applications, and industrial formulation.
For bulk procurement, packaging should protect the product from moisture and contamination. HOO CHEMTEC supplies Disodium EDTA in 25 kg moisture-proof bags, with custom packaging options available for specific customer requirements.
How Does Disodium EDTA Work as a Chelating Agent?
Disodium EDTA works by binding metal ions through multiple donor groups in its molecular structure, forming stable metal-EDTA complexes. This process reduces the concentration of free metal ions, preventing them from interfering with chemical formulations or catalyzing unwanted reactions.
EDTA contains multiple donor groups that can coordinate with a metal ion, creating a stable metal-EDTA complex. A simplified process looks like this:
Disodium EDTA → metal ion binding → stable metal-EDTA complex → reduced free-metal-ion activity
Disodium EDTA can interact with metal ions such as:
- Calcium (Ca²⁺)
- Magnesium (Mg²⁺)
- Iron ions (Fe²⁺, Fe³⁺)
- Copper (Cu²⁺)
- Other multivalent metal ions
Why Does Metal Ion Control Matter?
Free metal ions can interfere with chemical formulations in several ways. Calcium and magnesium contribute to water hardness, which can reduce the effectiveness of surfactants and cleaning agents. Iron and copper can catalyze unwanted oxidation reactions, causing discoloration, rancidity, and formula breakdown in cosmetic and food products.
When this chelating agent binds these ions, it reduces their availability for unwanted reactions. This can help:
- Control metal-ion interference
- Improve formulation stability
- Reduce the effect of water hardness
- Protect product appearance
- Improve the consistency of chemical processes
- Support cleaning and treatment formulations
The exact strength of the metal-EDTA complex depends on the metal ion, pH, temperature, and chemical environment.
What Are the Main Uses and Applications of Disodium EDTA?
Disodium EDTA is used across six primary industries: water treatment, cosmetics and personal care, detergents and cleaning products, food processing, pharmaceuticals, and laboratory analysis. Each application requires specific grades and purity levels, from industrial to food-grade and pharmaceutical-grade standards.
Disodium EDTA in Water Treatment
Disodium EDTA helps control metal ions in water and industrial process systems. Hard water contains calcium and magnesium ions that can react with other chemicals and contribute to deposits under suitable process conditions.
By binding these metal ions, the compound reduces their free concentration and helps control metal-ion-related problems. More precisely, Disodium EDTA can sequester calcium and magnesium ions and therefore reduce the effect of hardness ions in certain formulations and process systems.
Potential applications include:
- Industrial process water treatment
- Hard-water treatment
- Metal-ion control in process streams
- Industrial cleaning formulations
- Boiler water treatment chemicals
- Cooling system chemical formulations
However, Disodium EDTA should not be described as a universal replacement for conventional scale inhibitors. Its primary function is metal-ion sequestration. The correct treatment chemical depends on water chemistry, operating conditions, dosage, and the target scale.
Disodium EDTA in Cosmetics and Personal Care
Cosmetic formulations can contain trace metal ions from raw materials, water, pigments, and processing equipment. These metal ions can accelerate oxidation or affect product color and stability.
By binding these trace metal ions, Disodium EDTA helps reduce metal-catalyzed oxidation and improve formulation stability. It is therefore used in formulations such as:
- Shampoos
- Liquid soaps
- Creams and lotions
- Cleansing products
- Other personal care formulations
The main role is not to act as a surfactant or preservative. Instead, it functions primarily as a chelating agent that controls trace metal ions — helping to prevent discoloration and formula breakdown.
Disodium EDTA in Detergents and Cleaning Products
Water hardness can reduce the performance of cleaning formulations. Calcium and magnesium ions can interact with surfactants and other formulation components, affecting cleaning performance and formulation stability.
Disodium EDTA can bind these metal ions and reduce their interference. Typical applications include liquid detergents, cleaning products, personal care cleansers, and industrial cleaning formulations.
For strongly alkaline cleaning products, formulators should compare Disodium EDTA with Tetrasodium EDTA because the two salts have different pH characteristics.
Disodium EDTA in Food Processing
Disodium EDTA is permitted as a food additive in specific applications and functions primarily as a sequestrant by binding trace metal ions. This can help protect certain foods from metal-catalyzed oxidation and quality changes.
Approved as a food additive (E385) in many countries, applications can include:
- Canned foods
- Salad dressings
- Sauces and mayonnaise
- Beverage formulations
- Other permitted food products
Important: The exact permitted use, maximum level, labeling requirements, and grade depend on the target market and applicable food regulations. Buyers should never assume that industrial-grade Disodium EDTA can be used directly in food applications. Only food-grade material should be used, and buyers must confirm compliance with target market regulations.
Disodium EDTA in Pharmaceutical Applications
EDTA salts are used in certain pharmaceutical and medical formulations where metal-ion control is required. The specific salt, grade, dosage form, and applicable pharmacopoeial requirements depend on the intended application.
Pharmaceutical and medical formulations may use EDTA salts for specific metal-ion control and formulation purposes. However, pharmaceutical applications require a much higher level of quality control than general industrial applications. Buyers should confirm:
- Pharmaceutical grade
- Applicable pharmacopoeial requirements (USP, EP)
- Purity and impurity limits
- Heavy-metal limits
- Microbiological requirements where applicable
- Documentation and traceability
A supplier’s industrial-grade specification should not automatically be treated as a pharmaceutical specification.
Disodium EDTA in Laboratory and Analytical Chemistry
EDTA is widely used in analytical chemistry because it can form stable complexes with metal ions. Disodium EDTA is used to prepare buffer solutions, mask interfering metal ions in chemical analysis, and serve as a chelating agent in biochemical research and titration methods.
What Is the Difference Between Disodium EDTA and Tetrasodium EDTA?
The key difference between Disodium EDTA (EDTA-2Na) and Tetrasodium EDTA (EDTA-4Na) lies in their sodium content and solution pH. EDTA-2Na has two sodium ions and a mildly acidic pH of 4–5, while EDTA-4Na has four sodium ions and a strongly alkaline pH of 10.5–11.5. This difference determines their optimal applications.
One of the most common questions from chemical buyers is: What is the difference between EDTA-2Na and EDTA-4Na? Both are EDTA salts, but they do not behave identically in formulations.
| Feature | Disodium EDTA (EDTA-2Na) | Tetrasodium EDTA (EDTA-4Na) |
|---|---|---|
| Common name | Disodium EDTA | Tetrasodium EDTA |
| Sodium ions | 2 | 4 |
| pH (1% solution) | 4.0 – 5.0 | 10.5 – 11.5 |
| Chemical environment | Acidic to mildly acidic | Strongly alkaline |
| Solubility | Soluble in hot water; limited in cold water | Highly soluble in cold and hot water |
| Typical applications | Personal care, food, pharma, laboratory | Detergents, industrial cleaning, textile, water treatment |
| Main selection factor | Compatibility with formulation pH | Compatibility with alkaline formulations |
How to Choose the Right EDTA Salt for Your Formulation?
Choosing between Disodium EDTA and Tetrasodium EDTA depends on formulation pH, required solubility, target metal ions, process temperature, and regulatory requirements. The table below provides general guidance, but actual selection should be verified through laboratory testing.
There is no universal answer to which EDTA salt is best. The final choice should consider formulation pH, required solubility, metal ions to be controlled, process temperature, application, product grade, and regulatory requirements.
| Formulation Consideration | Typical Choice |
|---|---|
| Mildly acidic formulation (pH 4–7) | Disodium EDTA may be suitable |
| Strongly alkaline formulation (pH >10) | Tetrasodium EDTA is often preferred |
| Limited heating / cold process | Compare actual solubility data before selection |
| Cosmetics / personal care | Disodium EDTA is widely used |
| Industrial cleaning | Tetrasodium EDTA may be preferred in alkaline systems |
| Water treatment | Selection depends on water chemistry and treatment objective |
For industrial buyers, a supplier should provide technical documentation before bulk procurement.
Disodium EDTA vs EDTA Free Acid: What’s the Difference?
Disodium EDTA and EDTA free acid are different chemical forms. EDTA refers to ethylenediaminetetraacetic acid (CAS 60-00-4) with no sodium ions, while Disodium EDTA (CAS 6381-92-6) is the disodium salt with two sodium ions. The salt form is more water-soluble and easier to formulate than the free acid.
The difference affects formulation behavior:
| Property | EDTA (Free Acid) | Disodium EDTA (EDTA-2Na) |
|---|---|---|
| Chemical form | Free acid | Disodium salt |
| Sodium ions | None | Two |
| CAS number | 60-00-4 | 6381-92-6 |
| Typical role | Chelating agent / chemical raw material | Chelating agent / formulation ingredient |
| Solution behavior | More acidic | Mildly acidic (pH 4–5) |
Therefore, Disodium EDTA is not simply another name for EDTA acid. It is a specific salt form with its own CAS number, molecular weight, specifications, and formulation characteristics.
What Should Buyers Check Before Ordering Disodium EDTA in Bulk?
Before placing a bulk order for Disodium EDTA, buyers should verify chemical identity, hydrate form, assay, pH, heavy metals, iron, packaging, grade, CoA, and SDS/TDS documentation. These parameters ensure the product meets formulation requirements and regulatory standards.
Key items to verify before bulk procurement:
- Chemical identity — Confirm Disodium EDTA / EDTA-2Na / CAS 6381-92-6
- Hydrate form — Confirm dihydrate form (molecular weight varies by hydrate)
- Assay — Verify purity meets application requirements
- pH — Confirm 1% solution pH is within specification (4.0–5.0)
- Heavy metals — Verify limits meet regulatory or formulation requirements
- Iron — Critical for color-sensitive applications
- Packaging — Confirm moisture protection and container loading
- Grade — Industrial, food, cosmetic, or pharmaceutical grade
- CoA — Request batch-specific Certificate of Analysis
- SDS/TDS — Request Safety Data Sheet and Technical Data Sheet
How to Choose a Disodium EDTA Supplier?
Choosing a reliable Disodium EDTA supplier requires evaluating product identity, purity and impurities, grade, CoA documentation, packaging and logistics, and technical support capabilities. A professional supplier should provide consistent product quality and clear technical documentation for every batch.
Choosing a supplier involves more than comparing the price per metric ton. A reliable supplier should provide consistent product quality and clear technical documentation:
1. Check Product Identity
Confirm: Disodium EDTA, EDTA-2Na, CAS 6381-92-6, and the exact hydrate form. This prevents confusion between Disodium EDTA and other EDTA salts.
2. Check Purity and Impurities
Compare assay, heavy metals, iron, chloride, sulfate, and other parameters that affect your application.
3. Request a CoA
A batch-specific CoA gives you a better basis for quality evaluation than a generic product description.
4. Confirm the Grade
Industrial, food, cosmetic, laboratory, and pharmaceutical applications can have different requirements. Always confirm that the grade matches your intended application and target-market regulations.
5. Check Packaging and Logistics
For international procurement, evaluate packaging quality, container loading, port options, lead time, export documents, and shipping support.
6. Request Technical Documents
A professional chemical supplier should be able to provide TDS, SDS, CoA, packing information, and product specifications.
Why Source Disodium EDTA from HOO CHEMTEC?
HOO CHEMTEC supplies Disodium EDTA (EDTA-2Na) for industrial and formulated applications:
- Direct manufacturer with annual production capacity exceeding 35,000 metric tons
- Purity ≥99.0% with heavy metals below 5 ppm
- ISO 9001-certified laboratory with SGS certification
- Complies with USP, EP, and food-grade (E385) standards
- Exports over 3,000 tons of EDTA salts each month
- 98% on-time delivery rate with warehouses at major Chinese ports
- 25kg moisture-proof bags (25 MT per 20ft container) with custom packaging available
- Free samples for pre-order testing
- Expert technical support with over 15 years of formulation experience
HOO CHEMTEC can supply Disodium EDTA grades according to customer specification. Contact us for the current TDS and batch-specific CoA.
If you are evaluating Disodium EDTA for a new formulation or bulk procurement project, provide your target grade, application, quantity, packaging requirement, and destination. The supplier can then confirm the suitable specification and export arrangement.
Request a Disodium EDTA quotation from HOO CHEMTEC today.
How do I choose a Disodium EDTA supplier?
Compare product identity, purity, impurity limits, grade, CoA, TDS, SDS, packaging, supply capability, and export experience. For food, pharmaceutical, or other regulated applications, confirm that the supplier can provide the appropriate grade and documentation.
HOO CHEMTEC is a direct manufacturer of high-purity Disodium EDTA (EDTA-2Na) with ISO 9001 and SGS certifications. We serve customers in over 50 countries with annual exports exceeding 3,000 tons of EDTA salts. Contact us today for a quotation or free sample.
FAQ
What is Disodium EDTA?
Disodium EDTA is a disodium salt of ethylenediaminetetraacetic acid. The common commercial form is Disodium EDTA dihydrate, also called EDTA-2Na or disodium edetate. It acts mainly as a chelating agent that binds metal ions.
Is Disodium EDTA soluble in water?
Yes, Disodium EDTA can dissolve in water. However, it is soluble in hot water but has limited solubility in cold water. Actual dissolution behavior depends on the hydrate form, temperature, concentration, and product grade.
Is Disodium EDTA safe for food applications?
Yes, Disodium EDTA is approved as a food additive (E385) in many countries for specific applications. However, only food-grade Disodium EDTA should be used, and buyers must confirm compliance with target market regulations.
What is the difference between EDTA and Disodium EDTA?
EDTA refers to the free acid form (CAS 60-00-4) with no sodium ions, while Disodium EDTA (CAS 6381-92-6) is the disodium salt with two sodium ions. The salt form is more water-soluble and easier to formulate.
