High-Purity Solvents, Water Treatments

Ethylene Diamine Tetra (Methylene Phosphonic Acid) (EDTMP)

Ethylene Diamine Tetra (Methylene Phosphonic Acid), commonly known as EDTMP or EDTMPA (CAS: 1429-50-1), is a high-performance nitrogenous organic polyphosphonic acid. It is a member of the organic phosphonate family and serves as a functional analogue to EDTA, where the carboxylic acid groups are replaced by phosphonic acid groups. This structural shift provides EDTMP with superior sequestration capabilities and significantly higher thermal stability. In aqueous solutions, EDTMP dissociates into multiple anions, allowing it to chelate with various polyvalent metal ions—such as calcium, magnesium, iron, and copper—to form stable, water-soluble coordination complexes. It is particularly valued for its “threshold effect,” where sub-stoichiometric concentrations effectively inhibit scale precipitation. Due to its robust chemical stability under high-temperature and high-pH conditions, EDTMP is a critical additive in industrial water treatment, textile processing, and oilfield operations, where it functions as both a powerful sequestrant and a corrosion inhibitor.

Attributes

Key Features and Benefits

Superior Sequestration: Demonstrates exceptional ability to chelate polyvalent metal ions, particularly calcium, often surpassing EDTA in specific industrial environments.
High Thermal Stability: Maintains chemical integrity and scale-inhibiting performance at temperatures exceeding 200°C, making it ideal for high-pressure boiler systems.
Threshold Inhibition: Effectively prevents scale formation at dosages significantly lower than the stoichiometric requirements for metal ions.
Corrosion Protection: Acts as an efficient cathodic corrosion inhibitor when formulated with zinc salts or other inorganic phosphates.
Broad pH Tolerance: Remains chemically stable and active across a wide pH range, including highly alkaline cleaning solutions.
Low Toxicity: Generally considered to have a low toxicity profile with manageable environmental impact in industrial discharge.

Specifications

Technical Highlights

Chemical Structure: A hexapotential acid (C₆H₂₀N₂O₁₂P₄) capable of donating multiple protons for complex metal coordination.
Chelation Value: Typically sequesters 450–550 mg of CaCO₃ per gram of active acid at pH 7, depending on the purity grade.
Hydrolytic Stability: Highly resistant to hydrolysis compared to inorganic polyphosphates, ensuring long-term activity in recirculating systems.
Oxidation Resistance: Exhibits excellent stability in the presence of oxidizing biocides like chlorine or bromine.
Physical Forms: Available as a white crystalline powder (90% active) or a clear, amber aqueous solution (approx. 30% active).
Density & pH: The aqueous solution typically features a density of ~1.20–1.30 g/cm³ and a 1% solution pH of < 2.0.

Download Technical Data Sheet (TDS)

Practical industry uses

Applications

Industrial Water Treatment: Primary use in circulating cooling water systems and boilers to prevent calcium carbonate and calcium sulfate scaling.
Textile Industry: Serves as a stabilizer for hydrogen peroxide bleaching and a metal ion scavenger in dyeing processes to ensure color uniformity.
Oilfield Operations: Utilized in oilfield water injection systems and “squeeze” treatments to control scale in downhole equipment and transport pipelines.
Detergent Formulations: Integrated into industrial and institutional cleaners to enhance soil removal and prevent precipitation in hard water.
Metal Finishing: Applied in electroplating as a complexing agent and in metal surface treatment for oxide removal and passivating metal substrates.