The Sodium Salt of Diethylene Triamine Penta (Methylene Phosphonic Acid), commonly known as DTPMP·Na2, is a highly effective, multi-functional water treatment chemical. It is an organophosphonate prized for its excellent scale inhibition and chelation properties.
Here is a detailed overview of its properties and applications.
Key Properties & Specifications
DTPMP·Na2 is typically supplied as a red-brown to umber transparent liquid . As a disodium salt, its solution is weakly acidic.
Parameter Typical Value Notes
CAS Number 22042-96-2 A related heptasodium salt has CAS 68155-78-2.
Molecular Formula C₉H₂₆O₁₅N₃P₅Na₂
Appearance Red-brown to umber transparent liquid
Active Content 45.0 – 49.0% (as DTPMPA) Refers to the active acid content.
pH (1% aqueous) 2.0 – 3.0 Weakly acidic.
Density (20°C) 1.37 – 1.47 g/cm³
Total Phosphorus 37.0 – 40.0% (as PO₄³⁻)
Core Functions & Applications
DTPMP·Na2 serves multiple critical roles in industrial water treatment and other processes:
Scale Inhibition: It is a powerful scale inhibitor, particularly highly effective against barium sulfate (BaSO₄) scale . This makes it essential for oilfield water treatment and other high-hardness applications.
Chelating Agent: It acts as a highly efficient chelating agent, binding with metal ions to prevent them from forming insoluble precipitates.
Stabilizer: It can stabilize peroxide bleaching solutions and is used as a detergent auxiliary.
Common Application Areas: Industrial cooling water systems, boiler water treatment, oilfield water injection, municipal and industrial cleaning water, geothermal water treatment, and as a stabilizer in bleaching processes.
Usage, Storage & Safety
Dosage: The optimal dosage should be determined through experimentation based on specific water quality and system conditions.
Packaging: Typically supplied in 30 kg or 250 kg plastic drums.
Storage: Store in a cool, dry, and shaded indoor area. The typical shelf life is ten months.
Safety: The product is weakly acidic. Standard industrial safety measures should be followed during handling:
Avoid contact with skin and eyes.
In case of contact, rinse thoroughly with plenty of water.
A Note on Variants: There are other sodium salts of DTPMP, such as the pentasodium (DTPMP·Na5) and heptasodium (DTPMP·Na7) salts. These are generally neutral solutions (pH 6-8) or available in solid form , and are used in similar applications. The CAS number 68155-78-2 often refers to these higher-sodium salts.
From a regulatory perspective, DTPMP and its salts are not considered genotoxic hazards. However, like many strong chelators, they can potentially affect mineral homeostasis and may cause eye irritation, which are properties that should be noted by chemical safety professionals.