Disodium salt of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid HEDP•Na2
CAS No. 7414-83-7
Alias: Hydroxyethyl diphosphonic acid disodium, Sodium etiophosphate
Molecular formula C2H6O7P2 Na2
Relative molecular mass: 250
Structural formula
Ⅰ. Performance and use
HEDP·Na2 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. HEDP·Na2 can still play a good role in 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·Na2 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; HEDP·Na2 can be used as cleaning agent for metal and nonmetal, peroxide stabilizer and color fixing agent for bleaching and dyeing industry, and complexing agent for cyanide-free electroplating industry.
Ⅱ. Technical indicators
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Item
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Indicators
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--
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HG/T 2839-2010
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Appearance
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Colorless to yellowish transparent liquid
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White powdery solid
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Active component（HEDP）/%
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≥16.5
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74.0～79.0
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Active component（ HEDP·Na2）/%
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≥20.0
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≥90.0
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Dry weight loss /%
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--
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--
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pH（1% Aqueous solution）
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4.0～6.0
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4.0～6.0
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Density（20℃）/g·cm-3
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1.12～1.22
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--
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Fe content(Fe) /mg·L-1
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--
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≤20.0
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Phosphoric acid(PO43-)/%
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--
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≤0.5
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Phosphorous acid(PO33-)/%
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--
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≤1.5
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Chloride(Cl-)/%
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--
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≤0.1
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Ⅲ. Method of use
For scale inhibitor, the concentration is usually 2 ~ 20mg/L, for corrosion inhibitor, the concentration is usually 20-100mg/L, for cleaning agent, the concentration is usually 1000 ~ 2000mg/L, usually used in combination with polycarboxylic acid scale inhibitor dispersant.
Ⅳ. Packaging and storage
The HEDP·Na2 liquid shall be packed in plastic drums of 30kg or 250kg each, and the HEDP·Na2 solid shall be packed in plastic woven bags lined with polyethylene bags, each bag net weight of 25kg, which can also be determined according to the user's needs. Stored indoors in a cool place, solid storage period of 12 months, liquid storage period of 10 months.
Ⅴ. Safety protection
HEDP·Na2 is weak acid, pay attention to labor protection during operation, avoid contact with skin, eyes, etc., after contact, rinse with plenty of water.
