1-Hydroxyethylidene diphosphonic Acid
1-Hydroxyethylidene-1,1-diphosphonic acid
CAS: 2809-21-4
Molecular Formula: C2H8O7P2
1-Hydroxyethylidene diphosphonic Acid - Names and Identifiers
1-Hydroxyethylidene diphosphonic Acid - Physico-chemical Properties
| Molecular Formula | C2H8O7P2 |
| Molar Mass | 206.03 |
| Density | 1.45 (60% aq.) |
| Melting Point | 198~199℃ |
| Boling Point | 578.8±60.0 °C(Predicted) |
| Flash Point | 303.8°C |
| Water Solubility | Soluble in water. |
| Vapor Presure | 0Pa at 25℃ |
| Appearance | Powder |
| Color | white |
| Merck | 14,3863 |
| BRN | 1789291 |
| pKa | 1.35, 2.87, 7.03, 11.3(at 25℃) |
| PH | pH (1.7→100, 25℃) : 1.3～1.8 |
| Storage Condition | Sealed in dry,Room Temperature |
| Stability | Stable. Incompatible with strong oxidizing agents. |
| MDL | MFCD00070585 |
| Physical and Chemical Properties | Density 1.45 (60% aq.) |
| Use | Boiler and heat exchanger scale inhibitors and corrosion inhibitors, non-cyanide electroplating complexing agent, soap chelating agent, metal and non-metallic cleaning agent |
1-Hydroxyethylidene diphosphonic Acid - Risk and Safety
| Risk Codes | R37/38 - Irritating to respiratory system and skin. R41 - Risk of serious damage to eyes R22 - Harmful if swallowed |
| Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S39 - Wear eye / face protection. |
| UN IDs | UN 3265 |
| WGK Germany | 2 |
| RTECS | SZ8562100 |
| FLUKA BRAND F CODES | 10 |
| TSCA | Yes |
| HS Code | 29319090 |
| Hazard Class | 8 |
| Packing Group | II |
| Toxicity | LD50 oral in mouse: 1800mg/kg |
1-Hydroxyethylidene diphosphonic Acid - Upstream Downstream Industry
| Raw Materials | Acetic acid Acetic acid Phosphorus trichloride |
1-Hydroxyethylidene diphosphonic Acid - Nature
Open Data Verified Data
colorless to light yellow viscous liquid. The pure product is a colorless, amorphous Crystal, miscible with water. Soluble in water, methanol, ethanol. It has a large dissociation constant in water and can form stable chelates and complexes with metal ions. It can form a stable adduct with a compound containing active oxygen, and keep the active oxygen stable. Chlorine resistance is good. Industrial product content is generally 50% ~ 62% colorless to light yellow viscous transparent aqueous solution, is a kind of Polybasic acid, soluble in water. HEDP is an important chelating agent, which is stable with several metal ions and is not easy to hydrolyze. It is not decomposed under General light and heat conditions, but is not resistant to the action of oxidative biocide. About 30% of HEDP with 5mg/L of residual chlorine is decomposed.
Last Update：2025-06-10 22:55:16
1-Hydroxyethylidene diphosphonic Acid - Preparation Method
Open Data Verified Data
prepared by the reaction of phosphorus trichloride, glacial acetic acid and water. Alternatively, it is prepared by the reaction of orthophosphoric acid, acetic anhydride and acetyl chloride. It can also be prepared by reacting phosphorous acid with acetic anhydride. It is also possible to react with acetic anhydride from orthophosphoric acid.
Last Update：2025-06-10 22:55:16
1-Hydroxyethylidene diphosphonic Acid - Introduction
This product is an organic phosphonic acid scale and corrosion inhibitor, which can form stable complexes with iron, copper, zinc and other metal ions, and can dissolve oxides on the metal surface. It can play a good role in corrosion and scale inhibition at 250 ℃, is still stable at high pH value, is not easy to hydrolyze, and is not easy to decompose under general light and heat conditions. Acid and alkali resistance and chlorine oxidation resistance are better than other organic phosphonic acids (salts). It can form a six-ring chelate with metal ions in water, especially calcium ions, so it has a good scale inhibition effect and an obvious solution limit effect. When combined with other water treatment agents, it shows ideal Synergistic effect.
Last Update：2022-10-16 17:24:13
1-Hydroxyethylidene diphosphonic Acid - Application
Open Data Verified Data
is the boiler and heat exchanger Scale Inhibitor and corrosion inhibitor, non-cyanide plating complexing agent, soap chelating agent, metal and non-metallic cleaning agent. As a water treatment agent, HEDP has a stable structure and is not easily hydrolyzed. The corrosion and scale inhibition effect is good. HEDP is a cathode corrosion inhibitor, and the corrosion inhibition rate is about 4 times higher than that of inorganic polyphosphate. The inhibition effect of iron ion in water on HEDP is obviously affected. When the concentration of iron ion is more than 3mg/L, the inhibition effect of HEDP decreases exponentially with the increase of iron ion concentration. HEDP is used in combination with other corrosion inhibitors and scale inhibitors, such as chromate, polyphosphate, molybdate, silicate, nitrite, zinc salt, polycarboxylate and its derivatives, which has synergistic effect and can improve the efficacy. The dosage used is low, and the dosage used in the composite formulation is generally 2 to 5mg/L.
Last Update：2025-08-19 16:24:40
1-Hydroxyethylidene diphosphonic Acid - Safety
Open Data Verified Data
is a low toxicity product. 60% hydroxy ethylene diphosphonic acid aqueous solution, rat oral LD50:2400mg/kg; Rabbit skin absorption LD50 greater than 7940mg/kg. Corrosive. It has moderate irritation to eyes and skin, and the staff should be well protected. If the skin and eyes are accidentally touched, it should be rinsed with plenty of water immediately. During storage, ventilation should be maintained to avoid exposure to the sun. Avoid with strong alkali and storage, mixed transport.
Last Update：2022-01-01 09:28:52
1-Hydroxyethylidene diphosphonic Acid - Reference Information
| LogP | -3.5 |
| EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
| toxicity | the product is low in toxicity, and LD50 injected subcutaneously into mice is 486.4 mg/kg. |
| Preparation | Hydroxyethylenediphosphonic acid can be obtained by the reaction of acetyl chloride and phosphorous acid. |
| use | this product is the main material for cyanide-free electroplating. It is prepared into a cyanide-free copper plating solution with good bonding force of direct copper plating on sodium iron. The coating is smooth and good in color. The general dosage 60% content is 100~120 ml/l. The dosage of copper sulfate is 15~20g/L. In addition, before electroplating, the plated parts are immersed in 1% ~ 2% solution of this product to turn the plated parts into activated state, and then electroplating can improve the effect. Hydroxyethylenediphosphonic acid (HEDP) is a new type of chlorine-free electroplating complexing agent, which is used as the main agent for water quality stability in the circulating cooling water system and plays a role in corrosion and scale inhibition. This product is one of the organic multi-phosphonic acid-free water tablets. There are also some varieties of such products produced in China, such as aminomethylene phosphonic acid (ATMP):[CH2PO(OH)2]3N and ethylenediamine tetramethylene phosphate (EDTMP) and so on. Organic polyphosphonic acid is a kind of water treatment agent developed in the late 1960s and confirmed around the 1970s. The emergence of such treatment agents has taken a big step forward in water tablet technology. Compared with machine polyphosphate, organic multi-phosphonic acid has the characteristics of chemical stability of good medicine aunt, not easy to hydrolyze, high temperature tolerance and small dosage, and has the characteristics of mitigating scale corrosion. It is a kind of cathode corrosion inhibitor and a kind of non-chemical equivalent scale inhibitor. When used in combination with other water treatment agents, it shows ideal synergistic effect. It has excellent chelation energy for many metal ions such as calcium, magnesium, copper, zinc, etc., and even has good deactivation effect on inorganic salts of these metals such as CaSO4, CaCO3, MgSiO3, etc., so it is widely used in water treatment technology. Phosphorylation reagent, used for protected serine and pyranose. |
| Production method | After mixing phosphorus trichloride and glacial acetic acid, heating and distillation to obtain acetyl chloride (see 00510), and then react with phosphorous acid to obtain. Commercial products are viscous liquids with water dilution as the content 50%. Each ton of product consumes 931kg of phosphorus trichloride (95%) and 591kg of glacial acetic acid. Through the nucleophilic addition of diethylenetriamine and formaldehyde, the addition product is esterified with the hydrolysis product of phosphorus trichloride, and the product is neutralized. See EDTMP for details. In industry, glacial acetic acid and phosphoryl trichloride futures are usually used, and then the acylation product and phosphorus trichloride hydrolysis product condensation method. Add metered water and glacial acetic acid into the reaction kettle and stir evenly. Phosphorus trichloride was added dropwise under cooling, and the reaction temperature was controlled at 40~80 ℃. The reaction by-product hydrogen chloride gas is condensed and sent to the absorption tower to recover hydrochloric acid. Spilled acetyl chloride and acetic acid are condensed and returned to the reactor. After dropping phosphorus trichloride, the temperature is raised to 100~130 ℃ and refluxed for 4~5h. After the reaction is over, it is hydrolyzed with water vapor to evaporate the residual acetic acid and low boiling point. Products. |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-04-10 22:29:15
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Raw Materials for 1-Hydroxyethylidene diphosphonic Acid