EDTMP·Na8, EDTMPS, Octasodium Salt


EDTMPS is also known as EDTMP·Na8. It is the octasodium salt of ethylene diamine tetramethylene phosphonic acid. EDTMPS is nitrogenous organic polyphosphonic acid. This octasodium salt is a part of a cathodic corrosion inhibitor. Its corrosion inhibition is 3~5 times better than that of inorganic polyphosphate.

EDTMP·Na8 can be fully dissolved in water, innocuous, and no pollution to the environment. It has good chemical stability and thermal tolerance.

EDTMPS shows excellent scale inhibition ability under temperature 200℃. EDTMP·Na8 can dissociate into 8 positive-negative ions. Thus it can chelate with many metal ions to form a polymer reticulation complex. And to destroy the normal crystallization of calcium scale.

EDTMP·Na8 shows better antiscale effects to calcium sulfate and barium sulfate.

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Structure Formula:

EDTMPS structure formula


Item Index
Appearance Clear yellow to umber transparent liquid
Active component (EDTMPS), % 30.0 Min.
Organic phosphonic acid (as PO43-), % 10.0 Min.
Phosphorous acid (as PO33-), % 5.0 Max.
Phosphoric acid (asPO43-), % 1.0 Max.
Chloride (Cl), % 3.0 Max.
Density (20℃), g/cm3 1.25 Min.
pH (1% water solution) 9.5-10.5


EDTMPS can be used as a corrosion inhibitor in circulating cool water systems and boiler water. It is a chelating agent in the non-cyanogen electroplating industry and a water-softening agent in the printing & dyeing industry.


When used alone, 2~10mg/l is preferred. When built with HPMA by ratio ETDMP: HPMA=1:3, EDTMPS can be used for a low-pressure boiler. This octasodium salt can also be built with BTA, PAAS, and zinc salt.

Packing and Storage:

200L plastic drum, IBC(1000L), customers’ requirement. Storage for ten months in shady room and dry place.


Ethylene Diamine Tetra (Methylene Phosphonic Acid) Octasodium, EDTPO.


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