ATMP (Amino Trimethylene Phosphonic Acid)
CAS 6419-19-8 C3H12NO9P3
- CAS number
- 6419-19-8
- EC number
- 229-146-5
- Formula
- C3H12NO9P3
- Molar mass
- 299.05 g/mol
- HS code
- 2931.49
Supply of ATMP
- Grades
- Supplied mainly as about 50% aqueous acid, and as solid acid and sodium-salt grades. Specified by active content, with limits on phosphorous acid, phosphoric acid, chloride and iron. Standard grades allow up to about 2% chloride, so state a tighter limit where stainless steel or a chloride-sensitive formulation is involved.
- Packaging
- Plastic drums (about 250 kg) · 1,000 L IBC · 25 kg bags (solid grade)
- Documents
- CoA, SDS and TDS on request; certificate of origin where the destination requires it.
- Delivery
- Worldwide, including the United States, Canada, the United Kingdom, Germany and the rest of the EU, the United Arab Emirates, India, Singapore, Malaysia and Australia. Quoted EXW, FOB, CIF or DAP.
ATMP is a water-treatment chemical that stops limescale from forming in cooling towers, boilers and pipes. Very small amounts keep calcium dissolved in the water, so it does not build up as a hard crust on hot surfaces. It is one of the lowest-cost chemicals for this job and is widely used in industrial cooling water, oilfield water and cleaning products. It is usually sold as a liquid.
Technical details
ATMP is an aminophosphonate: one nitrogen atom carrying three methylenephosphonic acid groups. It is made from phosphorous acid, formaldehyde and ammonia or an ammonium salt, the same Mannich-type reaction that gives most aminomethylene phosphonates. It is a strong threshold inhibitor of calcium carbonate scale at low cost, and like every phosphonate it does not revert to orthophosphate in hot water as polyphosphates do. Its limits are oxidising biocides and very hard water. Chlorine and bromine break the molecule down and release orthophosphate, and at high calcium it can precipitate as calcium phosphonate, so chlorinated or very hard systems usually run HEDP or PBTC instead. Ehlinar supplies liquid acid, solid acid and sodium-salt grades.
Appearance: The 50% acid grade is a clear, colourless to pale-yellow liquid with a density of about 1.31–1.35 g/cm³. The solid acid is a white crystalline powder. Sodium salts are supplied as solutions.
Applications
How we supply
- Certificate of Analysis (CoA), lot-specific where available
- Safety Data Sheet (SDS / MSDS)
- Technical Data Sheet (TDS)
- Certificate of Origin / Certificate of Conformity
Independent third-party inspection can be arranged on request, with the agency and scope agreed per trade. Representative samples can be requested for qualification, subject to supplier availability. We recommend incoming quality control against the agreed CoA.
Quoted on standard Incoterms (e.g. EXW, FOB, CIF, DAP) as agreed per trade. Delivery region, packaging and grade are confirmed per quote.
Documents and services above are subject to supplier availability and confirmed per quote; nothing here is an offer.
Typical / indicative values — not a binding specification
| Property | Typical |
|---|---|
| Active content (liquid grade) | 50–51% |
| Density at 20 °C (liquid grade) | 1.31–1.35 g/cm³ |
| Chloride (standard grade) | ≤2% |
| pH (1% solution) | ≤2 |
Also known as
Aminotris(methylenephosphonic acid) · Nitrilotris(methylenephosphonic acid) · NTMP · Nitrilotrimethylphosphonic acid · Amino tri(methylene phosphonic acid)
Frequently asked questions
- Why does ATMP lose performance in chlorinated water?
- Oxidising biocides such as chlorine and bromine attack the aminomethylene phosphonate structure and split off orthophosphate. That removes inhibitor from the water and adds phosphate, which can itself form calcium phosphate scale. Systems that hold a continuous chlorine or bromine residual normally use HEDP or PBTC.
- Is ATMP the same as NTMP?
- Yes. ATMP, NTMP and nitrilotris(methylenephosphonic acid) are names for the same compound, CAS 6419-19-8. Confirm the CAS rather than the abbreviation, because DTPMP and EDTMP are related but different aminophosphonates.
- What is the difference between ATMP acid and its sodium salts?
- The acid is strongly acidic, about pH 2 at 1%. The sodium salts are partly or fully neutralised and suit neutral or alkaline formulations, such as many cleaners, where they save on alkali. Salt grades are quoted either as the salt or as acid equivalent, so confirm the basis on the quote.
- How much chloride does ATMP contain?
- Standard grades allow up to about 2%, left over from manufacture. Where chloride matters, for stainless steel or low-chloride formulations, specify a tighter limit and check it on the certificate of analysis.
- Does ATMP count toward phosphorus limits?
- Yes. It is about 31% phosphorus by weight, the highest share of the three phosphonates listed here, and that phosphorus counts toward total-phosphorus discharge limits. Phosphonates are not readily biodegradable and are mostly removed in treatment plants by adsorbing onto sludge.
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Related products
Figures and identifiers here are compiled from public references and provided for general information; they are indicative, not a specification. See all products.