HEDP-Na4 is the sodium salt of HEDP, an excellent inhibitor of calcium carbonate scale. HEDP-Na4 is mainly used as a metal corrosion inhibitor for low-pressure boiler water treatment, circulating water treatment, industrial municipal clean water, and swimming pool sterilization.

The solid state of HEDP-Na4 is white powder, easily soluble in water, moisture-absorbent; it is easy to be transported and suitable for use under severe cold conditions.

HEDP-Na4 belongs to organic phosphonate scale and corrosion inhibitor; it can form stable complexes with iron, copper, zinc and other metal ions, and can dissolve oxides on metal surface. It can dissolve the oxides on the metal surface. It still plays a good role of corrosion and scale inhibition under 250℃. HEDP-Na4 is widely used in electric power, chemical industry, metallurgy, fertilizer and other industrial circulating cooling water, low-pressure boiler, oil field water injection and oil pipeline scale and corrosion inhibition; HEDP-Na4 in the textile industry, can be used as metal and non-metal detergent, peroxide stabilizers in printing and dyeing industry and color-fixing agent, cyanide-free plating complex, additives for daily chemicals. In light textile industry, HEDP-Na4 can be used as metal and non-metal cleaning agent, peroxide stabilizer and color-fixing agent in printing and dyeing industry, non-cyanide electroplating complexing agent, additive of daily-use chemicals.

Definition of HEDP

HEDP is the abbreviation of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid. It is a commonly used water treatment agent, often used as scale and corrosion inhibitor in the field of water treatment, the molecular weight structural formula can be seen in the following chart, the product is widely used in industrial circulating cooling water system, printing and dyeing industry, electroplating industry and many other fields.
CAS No. 2809-21-4 EINECS No. 220-552-8
Molecular Formula C2H8O7P2 hedp molecular weight 206.02
hedp chemical structure

hedp chemical structure
Effects of HEDP on water quality
Scale inhibition

HEDP can form stable complexes with calcium, magnesium and other metal ions in water. For example, calcium and magnesium ions in water are easily combined with carbonate and other anions to form calcium carbonate, magnesium carbonate and other scale. The phosphonic acid group in HEDP can chelate with calcium and magnesium ions. It is like a “cage” wrapping up calcium and magnesium ions, preventing them from precipitating with carbonate and other anions, thus preventing the formation of scale. This complexation can effectively reduce the activity of calcium and magnesium ions in water, and reduce the deposition of scale on the surface of equipment (such as heat exchangers, pipe walls, etc.). - In industrial cooling water, if scale is deposited in large quantities, the heat exchange efficiency will be reduced. After using HEDP, due to the inhibition of scale generation, it can make the equipment maintain good heat conduction performance and improve the operating efficiency of the equipment.
Corrosion inhibition

HEDP is able to form a protective film on metal surfaces. Taking the surface of steel as an example, the phosphonic acid group in the HEDP molecule can be adsorbed on the surface of steel and form a dense protective film through chemical adsorption or physical adsorption. This film can prevent corrosive substances such as dissolved oxygen and chloride ions in water from coming into direct contact with the metal. Dissolved oxygen in water is an important factor causing metal corrosion, it will occur on the metal surface electrochemical corrosion reaction. The protective film formed by HEDP can effectively block the contact between oxygen and metal, thus slowing down the corrosion rate of metal and extending the service life of the equipment.
Effects on microorganisms

HEDP itself does not have strong bactericidal and algaecidal properties, but because it inhibits the formation of scale and fouling, it indirectly reduces the attachment substrate needed for microbial growth. Microorganisms (e.g., bacteria, algae, etc.) often need to attach to solid surfaces in water in order to grow and reproduce better. When HEDP prevents the formation of scale, it makes it difficult for microorganisms to find suitable attachment points, thus inhibiting microbial growth to a certain extent. However, if the microbial content in the water is originally high, HEDP alone may not be able to effectively control the microbial community, but also need to be used in conjunction with the use of other water treatment chemicals such as biocides.
Sodium salt products related to HEDP

hedp 4na

hedp 2na

HEDP•Na4 Granule

HEDP•K2

Other water treatment chemicals

ATMP PBTC DTPMPA EDTMPA HPAA PAPEMP BHMTPMPA HMDTMPA
Specialized manufacturer of hedp: Kairui Chemical

Sodium HEDP4 (tetrasodium hydroxyethylidenebisphosphonate, HEDP-Na4) and sodium HEDP2 (disodium hydroxyethylidenebisphosphonate, HEDP-Na2) are both sodium salt forms of HEDP, and they are distinctly different in a number of ways: -
The chemical structure and composition of

sodium HEDP4 is the product of the substitution of four acidic hydrogen atoms by sodium atoms in the molecule of HEDP, with the chemical formula C₂H₂O ₇P₂Na₄; HEDP2 sodium, on the other hand, is the product of the substitution of two acidic hydrogen atoms by sodium atoms in the HEDP molecule, with the chemical formula C₂H₄O₇P₂Na₂ . This structural difference gives rise to a range of different behavior in terms of chemical and physical properties . -Physical
Properties

In appearance, the solid state of sodium HEDP4 is usually a white powder, moisture-absorbent, easily soluble in water, convenient for transportation, and suitable for use in severe cold conditions; while sodium HEDP2 is usually a white crystal . In terms of solubility, both can be dissolved in water, but due to the different structure, at the same temperature, the same solvent conditions, their solubility will have a slight difference, but can meet most of the water treatment and other application scenarios on the dissolution and dispersion requirements. -Chemical
properties

from the acidity and alkalinity point of view, HEDP4 sodium 1% aqueous solution pH value of 10.0 - 12.0, alkaline; HEDP2 sodium is also alkaline, but the specific pH range and HEDP4 sodium there are differences. In terms of stability, HEDP2 sodium is still very stable at high pH, not easy to hydrolyze, not easy to decompose under general light and heat conditions, acid and alkali resistance, resistance to chlorine oxidation performance is better than other organic phosphoric acid (salt); HEDP4 sodium also has a better stability at 250 ℃ can still play a good corrosion and scale inhibition, but in some extreme conditions, the two stability will be different performance. - Application areas and effect differences

in the field of water treatment, both can form stable complexes with iron, copper, zinc and other metal ions, dissolve the metal surface oxides, scale and corrosion inhibition. But HEDP4 sodium is an excellent inhibitor of calcium carbonate scale, in the industrial circulating cooling water, low-pressure boilers, oilfield water injection and oil pipelines and other scenarios, to prevent the deposition of calcium carbonate scale effect is remarkable, so as to protect the normal operation of the system, reduce equipment corrosion and clogging; HEDP2 sodium, in addition to scale and corrosion inhibition, can be in water with the metal ions, especially calcium ions to form the hexacyclic chelating complexes, and therefore has a better scale inhibition effect and has obvious dissolution limitation effect. In addition to scale and corrosion inhibition, sodium HEDP2 can form hexacyclic chelates with metal ions in water, especially calcium ions, thus it has better scale inhibition and obvious solubility-limiting effect, and when it is used in combination with other water treatment agents, it shows ideal synergistic effect, and it has obvious advantages in the systems with complicated requirements on water quality and needing multiple water treatment agents. In the textile industry, HEDP4 sodium can be used as metal and non-metal cleaning agents, peroxide stabilizers and color-fixing agents in the printing and dyeing industry; HEDP2 sodium in addition to metal cleaning, but also commonly used in textile dyeing and color-fixing additives and other aspects.

Corrosion inhibitors are a class of chemicals that can effectively slow down the rate of corrosion of metals and play a key role in many fields.

From the point of view of the principle of action, corrosion inhibitor molecules will be adsorbed on the surface of the metal, the formation of a layer of dense protective film, this layer of film as if the metal put on the “protective clothing”, the metal and corrosive media such as acids, alkalis, salt solutions and humid air and so on isolate, thus inhibiting the occurrence of electrochemical corrosion of metal, chemical corrosion and other types of corrosion reactions, to Reduce the rate of metal loss, extend the service life of metal products.

In the industrial field, corrosion inhibitors are widely used. In oil extraction, downhole equipment at high temperatures for a long time, high pressure and full of corrosive media in harsh environments, corrosion inhibitors added to the oil pipeline and equipment, can greatly reduce metal corrosion, to ensure the continuity of mining operations, reduce equipment maintenance and replacement costs. Chemical production process involves a large number of strong acid, alkali and other corrosive chemicals, reaction kettles, pipelines and other equipment using corrosion inhibitors to protect, can stabilize the production process, to avoid corrosion leakage caused by safety accidents.

In the transportation industry, automobiles, ships, engine cooling systems, fuel systems are prone to corrosion, corrosion inhibitors into the coolant, fuel, can protect the radiator, cylinders, fuel pumps and other components, to maintain the normal operation of the equipment, reduce the chance of failure.

In the field of construction, once the steel reinforcement in the reinforced concrete structure is corroded, it will seriously affect the strength and stability of the building. Adding corrosion inhibitor concrete, can form a protective film on the surface of the steel reinforcement, resist the environment of chloride ions, carbon dioxide and other erosion of the steel reinforcement, to protect the long-term safety and stability of the building.

In daily life, household metal water pipes, heating pipes, faucets, etc., if the water contains a small amount of corrosion inhibitor, can also effectively prevent rust, extend the service life, to provide convenience for people's lives.

In short, corrosion inhibitors with its unique anti-corrosion effect, penetrate into industrial production, transportation, construction and many other areas of home, for the protection of metal materials, to ensure that the normal operation of production and life have made great achievements. It and the previously mentioned DTPMPA and other water treatment agents, although the focus of different functions, but are centered on the protection of equipment, optimize the operation of the system, and jointly help the development of various industries.

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