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2-Phosphonobutane-1,2,4,-tricarboxylic acid is the latest generation of internationally popular phosphine carboxylic acid, and it is one of the most widely used and best-performing products in the compounding of high-efficiency scale and corrosion inhibitors.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is especially suitable for water quality conditions of high temperature, high hardness, high alkalinity, high pH, and high concentration ratio, and has good scale inhibition performance for calcium carbonate scale and calcium phosphate scale.
2-Phosphonobutane-1,2,4,-tricarboxylic acid has low content of phosphoric, has structural features of both phosphoric acid and carboxylic acid group, which enable its excellent scale and corrosion inhibition properties.
CAS Number: 37971-36-1
Molecular Formula: C7H11O9P
Molecular Weight: 270.13
EINECS Number: 253-733-5
Synonyms: 2-PHOSPHONOBUTANE-1,2,4-TRICARBOXYLIC ACID, 37971-36-1, PBTC, 1,2,4-Butanetricarboxylic acid, 2-phosphono-, 2-Phosphono-1,2,4-butanetricarboxylic acid, 2-Phosophonobutane-1,2,4-tricarboxylic acid, phosphonobutanetricarboxylic acid, 2-Phosphonobutane-1,2,4-tricarbonic acid, EINECS 253-733-5, BAYHIBIT AM, EC 253-733-5, MAYOQUEST 2100, DEQUEST 7000, 306P37319L, DTXSID4027999, 3-Carboxy-3-phosphonohexanedioic Acid, UNII-306P37319L, MFCD01940753, PBTC tricarboxylic acid, SCHEMBL22514, DTXCID807999, 2Phosphonobutane1,2,4tricarbonic acid, AKOS007930701, FP45281, 2Phosphonobutane1,2,4tricarboxylic acid, 1,2,4Butanetricarboxylic acid, 2phosphono, Butanetricarboxylic acid, 2phosphono1,2,4, DB-049222, CS-0451914, NS00001823, P1857, Butanetricarboxylic acid, 2-phosphono-1,2,4-, PHOSPHONOBUTANETRICARBOXYLIC ACID [INCI], A823953, Q27255925, 2-Phosphonobutane-1,2,4-tricarboxylic acid 50% in water, 2-Phosphonobutane-1,2,4-tricarboxylic acid (ca. 50% in water), 2-Phosphonobutane-1,2,4-tricarboxylic acid, 50% aqueous solution, 253-733-5, 40372-66-5, 2-Phosphonobutane-1,2,4-tricarboxylic acid sodium salt, sodium 2-phosphonobutane-1,2,4-tricarboxylate2-PHOSOPHONOBUTANE-1,2,4-TRICARBOXYLIC ACID;2-PHOSPHONOBUTANE-1,2,4-TRICARBOXYLIC ACID;2-PHOSPHOBUTANE-1,2,4-TRICARBOXYLIC ACID;2,4-Butanetricarboxylicacid,2-phosphono-1;PBTC;PBTCA;2-phosphono-1,2,4-butanetricarboxylic;2-Phosphono-1,2,4-butanetricarboxylicacid
2-Phosphonobutane-1,2,4,-tricarboxylic acids antiscale property under high temperature is far better than that of organophosphines.
2-Phosphonobutane-1,2,4,-tricarboxylic acid can improve zinc salt solubility, has good chlorine oxidation tolerance and good composite synergy.
2-Phosphonobutane-1,2,4,-tricarboxylic acid, often abbreviated as PBTC, is a highly effective and widely used organophosphonate compound that serves as a scale inhibitor and corrosion inhibitor in industrial water treatment applications.
It is a colorless to pale yellow liquid, typically available as a 50% aqueous solution, and it possesses a unique chemical structure that includes one phosphonic acid group and three carboxylic acid groups, making it exceptionally versatile and reactive in chelation and complexation processes.
2-Phosphonobutane-1,2,4,-tricarboxylic acid has low content of phosphoric, has structural features of both phosphoric acid and carboxylic acid group, which enable its excellent scale and corrosion inhibition properties.
Its antiscale property under high temperature is far better than that of organophosphines.
2-Phosphonobutane-1,2,4,-tricarboxylic acid can improve zinc salt solubility, has good chlorine oxidation tolerance and good composite synergy.
The molecular structure of PBTC enables it to bind effectively with divalent and trivalent metal ions—such as calcium, magnesium, iron, and copper—which are commonly found in hard water systems and tend to form unwanted mineral scales or deposits on heat exchanger surfaces, pipelines, boilers, and cooling towers.
By forming stable, water-soluble complexes with these metal ions, PBTC prevents them from precipitating as scale, thereby protecting equipment and improving the efficiency and lifespan of water systems.
In addition to its excellent anti-scaling performance, 2-Phosphonobutane-1,2,4,-tricarboxylic acid also exhibits strong corrosion inhibition properties, particularly when used in combination with zinc salts, polycarboxylates, or azoles in multi-component water treatment formulations.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is especially valued in systems operating at high pH levels and elevated temperatures, where traditional phosphonates or polyphosphates might break down or lose effectiveness.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is often used in cooling water systems, reverse osmosis units, oilfield injection water, geothermal plants, and industrial boilers, where it helps prevent the formation of calcium carbonate, calcium sulfate, and other scale-forming salts.
Its chemical stability, low phosphorus content, and biodegradability make it more environmentally friendly than some older phosphate-based scale inhibitors, making it a preferred choice for industries looking to comply with strict environmental discharge regulations.
Moreover, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is characterized by a strong threshold inhibition effect, meaning it can effectively prevent scale formation even when used at very low concentrations—sometimes in the range of just a few parts per million (ppm).
This high efficiency makes it cost-effective and reduces the overall chemical load in treated water systems.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is also known by several other names and identifiers, including its CAS number 37971-36-1, EINECS number 253-733-5, and various trade names such as BAYHIBIT AM, DEQUEST 7000, and MAYOQUEST 2100.
2-Phosphonobutane-1,2,4,-tricarboxylic acid may also appear in scientific literature or chemical catalogs as 1,2,4-butanetricarboxylic acid, 2-phosphono-, or 3-carboxy-3-phosphonohexanedioic acid, reflecting its structural features.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is the latest generation of internationally popular phosphine carboxylic acid, and it is one of the most widely used and best-performing products in the compounding of high-eciency scale and corrosion inhibitors.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is especially suitable for water quality conditions of high temperature, high hardness, high alkalinity, high pH, and high concentration ratio, and has good scale inhibition performance for calcium carbonate scale and calcium phosphate scale.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is a very eective scale inhibitor used in various industrial applications.
2-Phosphonobutane-1,2,4,-tricarboxylic acid has the dispersion property.
2-Phosphonobutane-1,2,4,-tricarboxylic acid's anions get adsorbed by inorganic particles in the water giving it the dispersion ability.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is a good corrosion inhibitor for carbon steel.
Hence, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is part of all organic water treatment programs.
2-Phosphonobutane-1,2,4,-tricarboxylic acid used as corrosion and scale inhibitor to treat industrial water.
2-Phosphonobutane-1,2,4,-tricarboxylic acid has excellent complexing ability with Ca2+, Zn2+, Cu2+, Mg2+ plasma. Suitable for use in the pH range of 7.0 to 9.5.
2-Phosphonobutane-1,2,4,-tricarboxylic acid can be operated under high temperature, high hardness and high alkalinity conditions.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is a good corrosion and scale inhibitor, widely used in the anti-scaling treatment of circulating cooling water systems and oileld water injection systems; a good corrosion and scale inhibitor, widely used in the antiscaling treatment of circulating cooling water systems and oileld water injection systems.
2-Phosphonobutane-1,2,4,-tricarboxylic acid used as a corrosion and scale inhibitor to treat industrial water.
Melting point: -15 °C
Boiling point: 545.2 ± 60.0 °C (Predicted)
Density: 1.25 (50% aq.)
vapor pressure: 0 Pa at 25 ℃
refractive index: 1.579
solubility: Completely miscible in water
form: clear liquid
pKa: 1.14 ± 0.10 (Predicted)
color: Colorless to Light yellow
Water Solubility: 909 g/L at 20 ℃
InChIKey: SZHQPBJEOCHCKM-UHFFFAOYSA-N
LogP: -1.66 at 25 ℃
2-Phosphonobutane-1,2,4,-tricarboxylic acid is compatible with a wide variety of other water treatment additives, including polyacrylic acid, zinc salts, benzotriazole, tolyltriazole, molibdates, and organophosphonates like HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) and ATMP (aminotris(methylenephosphonic acid)).
When formulated together, these compounds can act synergistically, offering broader protection against scale, corrosion, and metal ion precipitation.
2-Phosphonobutane-1,2,4,-tricarboxylic acid’s relatively low phosphorus content compared to ATMP or HEDP also makes it more favorable in regions with phosphorus discharge limits or eutrophication concerns.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is colorless or light yellow transparent liquid.
Has excellent scale and corrosion inhibition properties.
Acid resistance, alkali resistance, oxidant resistance when pH>14, it still does not hydrolyze, and the thermal stability is good.
One of the standout features of 2-Phosphonobutane-1,2,4,-tricarboxylic acid is its exceptional thermal and hydrolytic stability.
2-Phosphonobutane-1,2,4,-tricarboxylic acid remains stable in alkaline conditions and high-temperature environments, unlike some traditional water treatment agents such as polyacrylates or phosphates, which may decompose, hydrolyze, or lose efficacy under those conditions.
This stability makes PBTC ideal for cooling circuits, steam systems, and geothermal facilities where operating temperatures can exceed 80–100°C for prolonged periods.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is mainly due to superior stability to chlorine, bleach and bromine.
In cooling water PBTC performs well at high PH or temperatures.
2-Phosphonobutane-1,2,4,-tricarboxylic acid further shows high eectiveness in high alkaline solutions such as industrial cleaners.
2-Phosphonobutane-1,2,4,-tricarboxylic acid, with its excellence stability against chlorine, high temperatures and high alkali conditions, is used as scale and corrosion inhibitor and as stabilizer for Zinc salts and Calcium salts in aqueous systems.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is a low phosphorus chemical containing organophosphonate, which is known to be a highly eective threshold scale inhibitor.
In other words, at very low (ppm level) levels, sub-stoichiometric concentrations calculated on hardness of water, 2-Phosphonobutane-1,2,4,-tricarboxylic acid acts as excellent scale inhibitor for carbonates, sulfates and phosphates.
2-Phosphonobutane-1,2,4,-tricarboxylic acid has good chelating ability for heavy metals.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is a weaker complexing agent for metals than EDTA.
Hence, 2-Phosphonobutane-1,2,4,-tricarboxylic acid eliminates the remobilization of heavy metals from sediments.
2-Phosphonobutane-1,2,4,-tricarboxylic acid also has excellent tolerance towards chlorine and hypo-chlorites in the presence of bromine where most of the other phosphonates degrade extremely fast.
2-Phosphonobutane-1,2,4,-tricarboxylic acid's excellent thermal stability at various pH ranges, enables it to remain eective even at high pH levels and temperatures
2-Phosphonobutane-1,2,4,-tricarboxylic acid functions not only as a scale inhibitor and corrosion inhibitor but also as a chelating agent with high affinity for multivalent metal ions.
Its structure allows it to coordinate multiple metal centers simultaneously, which makes it particularly effective in sequestering metal ions that would otherwise catalyze oxidation reactions or promote mineral buildup in aqueous systems. Unlike simpler phosphonates, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is less likely to precipitate in the presence of calcium, even at elevated concentrations, making it especially suited for use in hard water environments or high-stress industrial systems.
In cooling tower and closed-loop water systems to maintain heat exchanger efficiency and prevent fouling.
As a membrane-compatible scale inhibitor that prevents mineral scaling without damaging sensitive filtration membranes.
In enhanced oil recovery (EOR) and downhole applications where scale control is vital under high temperature and salinity.
To control calcium scale formation during high-temperature dyeing or scouring processes.
To minimize scaling in process water circuits and reduce the frequency of maintenance shutdowns.
Where high mineral content and extreme temperatures make scale control critical for long-term viability.
From an environmental standpoint, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is considered to have low bioaccumulation potential and is readily biodegradable under aerobic conditions.
Its decomposition products are typically non-toxic and do not lead to persistent environmental pollutants.
This makes 2-Phosphonobutane-1,2,4,-tricarboxylic acid a preferred choice in environmentally sensitive regions, especially where wastewater discharge regulations are becoming more restrictive.
In terms of human safety, 2-Phosphonobutane-1,2,4,-tricarboxylic acid solutions are usually non-volatile, non-flammable, and exhibit low acute toxicity.
However, as with most acidic compounds, prolonged skin or eye contact can cause mild to moderate irritation, and appropriate PPE (gloves, goggles) should be used during handling.
In industrial settings, it is often accompanied by Safety Data Sheets (SDS) and classified under appropriate GHS labeling for chemical safety.
Uses:
2-Phosphonobutane-1,2,4,-tricarboxylic acid is the most widely used in the compounding of high-efficiency scale and corrosion inhibitors, is one of the products with the best performance, and is also an excellent stabilizer for zinc salts.
It is widely used in the corrosion and scale inhibition of circulating cooling water system and oilfield water injection system, especially suitable for compounding with zinc salt and copolymer.
It can be used as a chelating agent and metal cleaning agent in the washing industry.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is used in the following products: washing & cleaning products and water treatment chemicals.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is used in the following areas: formulation of mixtures and/or re-packaging.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is used for the manufacture of: .
Other release to the environment of this substance is likely to occur from: indoor use as processing aid, outdoor use as processing aid, indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters) and outdoor use in close systems with minimal release (e.g. hydraulic liquids in automotive suspension, lubricants in motor oil and break fluids).
2-Phosphonobutane-1,2,4,-tricarboxylic acid is the most widely used in the compounding of high-eciency scale and corrosion inhibitors, is one of the products with the best performance, and is also an excellent stabilizer for zinc salts.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is widely used in the corrosion and scale inhibition of circulating cooling water system and oileld water injection system, especially suitable for compounding with zinc salt and copolymer.
2-Phosphonobutane-1,2,4,-tricarboxylic acid can be used as a chelating agent and metal cleaning agent in the washing industry.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is a high ecient agent as scale and corrosion inhibitor.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is the excellent stabilizer for zinc salt.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is widely used in circulating cool water system and oileld rell water system as scale and corrosion inhibitor, suitable to composite with zinc salt and copolymer.
2-Phosphonobutane-1,2,4,-tricarboxylic acid can be used in situations of high temperature, high hardness, high alkali and high concentration index.
In lavation elds, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is used as chelating agent and metal detergent.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is frequently used in reverse osmosis (RO) and desalination systems as a membrane-compatible antiscalant, where it plays a critical role in preventing scale formation on delicate membrane surfaces.
Its excellent performance at low concentrations and its ability to remain stable in high-pressure, high-recovery systems makes it ideal for protecting RO membranes from fouling caused by calcium carbonate, calcium sulfate, and barium/strontium sulfate—common salts in seawater and brackish water sources.
In the oil and gas industry, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is employed in enhanced oil recovery (EOR) processes and water injection systems, where mineral scaling from high-salinity formation water is a major concern.
Its ability to function effectively under extreme temperature and pressure conditions, as well as in the presence of high ionic strength brines, makes it a reliable additive for maintaining flow efficiency in downhole and surface equipment over long periods.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is highly valued in geothermal power plants, where naturally occurring geothermal fluids often contain high concentrations of scale-forming minerals like silica, calcium, and iron.
In these systems, it acts as a threshold inhibitor, meaning it can prevent crystal growth even when used in very low concentrations, helping operators reduce maintenance frequency, extend equipment life, and maintain consistent energy output in an environmentally sustainable way.
Although not as common as in water treatment, 2-Phosphonobutane-1,2,4,-tricarboxylic acid can also be incorporated into industrial and institutional cleaning products, where it serves as a chelating agent that helps soften hard water and prevent soap scum or scale formation during cleaning.
In this role, it enhances the performance of alkaline cleaners, particularly in regions with very hard water, where mineral interference can reduce cleaning effectiveness.
Although far less common, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is listed under the INCI name (International Nomenclature of Cosmetic Ingredients) "Phosphonobutanetricarboxylic Acid", and may be used in certain formulations of personal care products as a chelating agent to improve product stability by preventing unwanted interactions between metal ions and other ingredients in the formulation.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is used in the following products: laboratory chemicals, metal working fluids, water treatment chemicals, heat transfer fluids, washing & cleaning products, non-metal-surface treatment products, polishes and waxes and cosmetics and personal care products.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is used in the following areas: formulation of mixtures and/or re-packaging.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is used for the manufacture of: .
Release to the environment of 2-Phosphonobutane-1,2,4,-tricarboxylic acid can occur from industrial use: as processing aid, in processing aids at industrial sites and of substances in closed systems with minimal release.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is a high efficient agent as scale and corrosion inhibitor.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is the excellent stabilizer for zinc salt.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is widely used in circulating cool water system and oilfield refill water system as scale and corrosion inhibitor, suitable to composite with zinc salt and copolymer.
2-Phosphonobutane-1,2,4,-tricarboxylic acid can be used in situations of high temperature, high hardness, high alkali and high concentration index.
In lavation fields, it is used as chelating agent and metal detergent.
One of the most prominent uses of 2-Phosphonobutane-1,2,4,-tricarboxylic acid is in industrial water treatment systems, particularly in cooling towers, boilers, and circulating water systems, where it functions as a highly effective scale and corrosion inhibitor.
By forming stable, water-soluble complexes with metal ions such as calcium, magnesium, and iron, 2-Phosphonobutane-1,2,4,-tricarboxylic acid helps to prevent the formation of scale deposits on equipment surfaces and internal pipe walls, which, if left untreated, can drastically reduce thermal efficiency, increase energy costs, and lead to mechanical failure.
In pulp and paper manufacturing, 2-Phosphonobutane-1,2,4,-tricarboxylic acid is used in process water systems to inhibit the deposition of scale-forming salts and reduce corrosion in process piping, heat exchangers, and digesters.
Its stability under high pH conditions is especially useful in alkaline pulping processes such as the kraft method, where traditional phosphates or polyacrylates may degrade or become ineffective over time.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is employed in textile dyeing and finishing operations, where scale control is important to prevent spotting, streaking, or uneven coloration during high-temperature processing.
By sequestering metal ions in the water, it allows for more consistent dye uptake and helps protect heating equipment from mineral fouling, improving both fabric quality and equipment longevity.
Safety Profile:
Although 2-Phosphonobutane-1,2,4,-tricarboxylic acid is not considered highly toxic, it can cause irritation to the skin and eyes, especially in its concentrated (50%) aqueous solution.
Direct contact may result in redness, stinging, or discomfort, so it's important to wear protective gloves and safety goggles when handling it in industrial or lab settings.
2-Phosphonobutane-1,2,4,-tricarboxylic acid has low volatility, but if it is sprayed or misted (for example, during cleaning, spraying, or accidental spills), inhalation of fine droplets may cause mild respiratory tract irritation.
Inhalation exposure may lead to coughing, throat discomfort, or shortness of breath, especially in poorly ventilated areas.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is acidic in nature (pH ~1.0–2.0 in concentrated solution), and may act as a mild corrosive to some materials and tissues.
Prolonged contact with metal surfaces may cause corrosion, especially on carbon steel, although stainless steel is generally more resistant.
As with many organic acids, 2-Phosphonobutane-1,2,4,-tricarboxylic acid should not be mixed with strong oxidizing agents (e.g., nitric acid, hydrogen peroxide) as this could result in chemical reactions that may release heat or hazardous byproducts.
Always store separately from reactive substances.
2-Phosphonobutane-1,2,4,-tricarboxylic acid is considered low in acute aquatic toxicity, but it still should not be discharged directly into natural waterways without proper treatment.
It is partially biodegradable, but in high concentrations, it can disrupt water chemistry and affect microbial ecosystems.
It is recommended to follow local discharge regulations when disposing of PBTC-containing wastewater.
