Shandong Kairui Chemistry Co., Ltd. is located in Xuecheng Chemical Industrial Zone of Zaozhuang City, plant size is around 67,000 m2, adopts advanced continuous mass production technology and DCS automatic control system. Built with 5 workshops for Phosphonates, Polycarboxylic Polymers, Biocides etc., company's monomers production capacity achieves 280,000 tons per year. Besides industrial water treatment, our products are also widely used in oilfield, detergents, textile & dyeing, paper-making, seawater desalination and other fields.

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HEDP, or hydroxyethylidene diphosphonic acid, plays a vital role in a number of fields and has a wide range of applications.

In terms of the underlying mechanism of action, HEDP exhibits strong chelating properties due to its unique chemical structure containing hydroxyl and phosphonic acid groups. It combines precisely and strongly with metal ions such as calcium, magnesium and iron in water to form stable chelates. This chelating effect is like putting a “shackle” on the metal ions, preventing them from free movement and aggregation, thus effectively preventing the formation of limescale from the source. Once the scale is formed, it will adhere to the surface of pipes and equipment, which not only affects the heat transfer efficiency, but also may cause pipe blockage and equipment damage, and HEDP can precisely solve this problem.

In the industrial field, it is the “guardian angel” of the industrial circulating water system. Industrial production of a large number of water circulation, water temperature repeatedly rise and fall, the increase in impurities in the water, it is very easy to cause scale and corrosion problems. HEDP as a water quality stabilizer to join them, on the one hand, continue to inhibit the generation of scale, so that the cooling pumps, heat exchangers, pipelines and other key equipment free from scale trouble, and always maintain a high efficiency of the heat exchange efficiency, to protect the smooth production process; on the other hand, it can also be with the corrosion inhibitor tacit cooperation! On the other hand, it also works well with corrosion inhibitors to build a protective film on the metal surface, and HEDP strengthens this protective effect. Under the double guarantee, it greatly slows down the corrosion rate of the metal, reduces the high cost of frequent maintenance and replacement of equipments, and ensures the stable and efficient operation of industrial production.

In the central air conditioning water system, HEDP is also indispensable. Central air-conditioning operating conditions are complex and variable, the water temperature, water quality changes at any time, the water quality requirements are extremely high, HEDP with its own good adaptability, whether it is high temperature and humidity in the summer, or low temperature and dry winter, can flexibly respond to different water temperatures, water quality conditions, to ensure that there is no obstacle to the flow of water in the system, the condenser, the evaporator, and other core components of the heat dissipation is normal, so that air-conditioning system is always maintained in the best energy efficiency, reducing energy consumption, saving the user the energy. This reduces energy consumption, saves users money on electricity bills and extends the service life of the air conditioner.

For hot water heating systems, HEDP is the key to keeping residents warm through the winter. As hot water circulates in the heating pipes, the impurities carried in the water accumulate over time, which can easily lead to clogged pipes, corrosion and perforation, affecting the effect of heating, and the addition of HEDP can keep the water clean at all times, preventing scaling inside the radiators and pipelines, so that the heat can be uniformly and smoothly transmitted to each household, making the homes of the residents as warm as spring at all times. Moreover, it effectively slows down pipe corrosion, greatly extending the overall service life of the heating system and reducing the frequency and cost of maintenance before the heating season.

Compared with traditional water treatment agents, the advantages of HEDP are obvious. Compared with simple corrosion inhibitor, although it also synergistic corrosion inhibition, but more focused on scale prevention and control, with strong chelating and scale inhibition ability as the core competitiveness; compared with DTPMPA and other products with chelating ability, in the use of low-concentration scenarios, HEDP cost-effective and only a small amount of injection can achieve excellent scale inhibition results, saving a lot of pharmaceutical costs for the enterprise and the user, and really achieve high efficiency and economy. It is really efficient and economical.

In short, HEDP with its excellent performance, a full range of penetration into industrial production, commercial operations and daily life of various types of systems that require stable water quality, to become the mainstay of modern water treatment, and continue to create a comfortable and efficient production and living environment for people.

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.