1-Hydroxy Ethylidene-1,1-Diphosphonic Acid HEDP
CAS No. 2809-21-4
Nicknames: hydroxyethyl diphosphonic acid, HEDPA, (1-hydroxyethyl) diphosphonic acid, 1-hydroxyethyl 1, 1-diphosphate
Molecular formula C2H8O7P2
Relative molecular mass: 206.02
Structural formula
Ⅰ. Performance and use
HEDP is an organic phosphonic acid scale inhibitor and corrosion inhibitor, which can form stable complexes with iron, copper, zinc and other metal ions and dissolve oxides on the metal surface. It can still play a good role of corrosion inhibition and scale inhibition at 250℃, and it is still very stable at high pH, not easy to hydrolyze, and not easy to decompose under general photothermal conditions. Acid and alkali resistance, resistance to chlorine oxidation than other organic phosphonic acid (salt) better. It can form a six-ring chelate with metal ions in water, especially calcium ions, so it has a better scale inhibition effect and an obvious dissolution limit effect. When used in combination with other water treatment agents, it shows an ideal synergistic effect.
HEDP solid belongs to high purity products, suitable for cold areas in winter; It is especially suitable for cleaning agent and daily chemical additive in electronic industry.
HEDP is widely used in power, chemical, metallurgy, chemical fertilizer and other industrial circulating cooling water system, medium and low pressure boiler, oil field water injection and oil pipeline scale and corrosion inhibition; In light textile industry, it can be used as cleaning agent of metal and nonmetal, peroxide stabilizer and color fixing agent of bleaching industry, complexing agent of cyanide-free electroplating industry, and radioactive element carrier agent of pharmaceutical industry.
Ⅱ. Technical indicators Accord with GB/T 26324-2010 HG/T 3537-2010
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Item
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Indicators
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50%Liquid
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60%Liquid
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Solid
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|
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GB/T
26324-2010
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--
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HG/T
3537-2010
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Appearance
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A colorless or yellowish transparent liquid
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A colorless or yellowish transparent liquid
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White crystal particle
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Active component（HEDP）/%
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≥50.0
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≥60.0
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--
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Phosphite（PO33-）/%
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≤2.0
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≤2.0
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≤0.8
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Phosphate（PO43-）/%
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≤0.8
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≤0.8
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≤0.5
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Chloride（Cl-）/%
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≤0.02
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≤0.02
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≤0.01
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pH（1% Aqueous solution）
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1.5-2.0
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1.5-2.0
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1.5-2.0
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Sensity（20℃）/g·cm-3
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≥1.36
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≥1.40
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--
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Calcium chelating values/mg·g-1
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≥450
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≥500
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--
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Iron(Fe2+)content/mg·L-1
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≤20.0
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≤20.0
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≤10
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Active constituent（HEDP·H2O）/%
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--
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--
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≥97.0
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Ⅲ. Method of use
The concentration of HEDP as scale inhibitor is generally 1 ~ 10mg/L, and that of corrosion inhibitor is generally 10-50mg/L. As a cleaning agent, the general use concentration of 1000 ~ 2000mg/L; Usually used in conjunction with polycarboxylic acid scale inhibitor dispersants. When used in other industries, the dosage should be determined according to the test.
Ⅳ. Packaging and storage
HEDP liquid is packed in plastic drums of 30Kg or 250Kg each. HEDP solids are packed in polythene lined plastic woven bags, each bag net weight 25kg, also available upon request. Store in indoor cool and ventilated place, moistureproof, storage period of 12 months.
Ⅴ.Safety protection
HEDP is acidic, pay attention to labor protection when operating, should avoid contact with the skin, eyes, etc., after contact should be immediately washed with plenty of water.
