| HS Code | 703053 |
| Productname | EDTA MgNa2 |
| Chemicalname | Ethylenediaminetetraacetic acid magnesium disodium salt |
| Synonyms | Magnesium disodium EDTA; MgNa2EDTA; Disodium magnesium ethylenediaminetetraacetate; EDTA magnesium disodium salt |
| Casnumber | 14402-88-1 |
| Einecscode | 238-372-3 |
| Molecularformula | C10H12MgN2Na2O8 |
| Molecularweight | 358.50 g/mol (anhydrous) |
| Appearance | White crystalline powder |
| Odor | Odorless |
| Assay | ≥98.0% |
| Solubility | Soluble in water; practically insoluble in common organic solvents |
| Ph | 6.0-8.0 (1% aqueous solution, 25°C) |
| Chelatingproperty | Strong chelating agent; forms stable water-soluble complexes with metal ions |
| Meltingpoint | >300°C (decomposes) |
| Storageconditions | Store in a cool, dry, well-ventilated area with container tightly closed |
| Stability | Stable under normal storage conditions |
| Hazardclass | May cause eye and skin irritation; low acute toxicity |
| Incompatibilities | Strong oxidizing agents |
| Chemicalfamily | Aminopolycarboxylic acid chelate |
| Ionform | Magnesium-sodium salt |
As an accredited EDTA MgNa2 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | EDTA MgNa2 is packaged in 25 kg net, sealed polyethylene-lined fiber drums with secure lids for safe storage and transport. |
| Container Loading (20′ FCL) | EDTA MgNa2 loaded in a 20′ FCL container: palletized, shrink-wrapped, labeled, and secured for safe ocean transport. |
| Shipping | EDTA MgNa2 (magnesium disodium EDTA) is not classified as dangerous goods for transport. It has no UN number, hazard class, or packing group. Ship as a non-hazardous chemical in sealed, labeled containers at ambient temperature, protected from moisture, and according to local regulations. |
| Storage | Store EDTA MgNa2 in a cool, dry, well-ventilated area. Keep containers tightly closed and properly labeled. Protect from moisture, heat, and direct sunlight. Avoid dust generation and inhalation. Keep separate from strong oxidizers, acids, and bases. Use appropriate secondary containment. Store away from food, drink, and animal feed. Follow the safety data sheet and local regulations for handling and storage. |
| Shelf Life | Typically 2–5 years when stored dry, sealed, at room temperature, protected from light; aqueous solutions are less stable. |
In continuous pad-steam bleaching of cotton woven goods, residual iron and manganese in process water initiate Fenton-type decomposition of hydrogen peroxide before the whiteness target is reached, producing hydroxyl radicals that depolymerise cellulose and reduce tensile strength. Ethylenediaminetetraacetic acid magnesium disodium salt, CAS 14402-88-1, is added to the saturator liquor at 0.2–0.6 g/L, together with 25–35 g/L hydrogen peroxide on a 50 wt% basis, 8–12 g/L sodium silicate, and sufficient caustic soda to hold pH 10.8–11.2. The ligand exhibits selective metal exchange because Fe(III)-EDTA and Mn(II)-EDTA log K values are 25.10 and 13.87 respectively, while Mg(II)-EDTA is only 8.69; magnesium is displaced when a higher-stability contaminant enters the hexadentate coordination sphere. This prevents dissolved iron from cycling between Fe(III) and Fe(II) oxidation states at the cellulose surface during the 15–20 min saturated steam dwell at 100–102°C in a continuous pad-steam range equipped with a 2-roll pad mangle set to 70–80% liquor pickup. Residual peroxide concentration is checked by potassium permanganate titration according to AATCC TM 102, and fabric strength loss is assessed by ASTM D5035; a residual peroxide drop below 10% of initial charge together with tensile strength loss above 25% indicates that incoming water metal load requires higher chelant addition. Incoming process water is screened by inductively coupled plasma optical emission spectrometry according to ISO 11885 for iron, manganese, and copper; when combined iron and manganese exceed 0.5 mg/L, the chelant dose is raised to 0.8 g/L. The crystalline product is dissolved in a side tank with acid-resistant stainless steel agitation, and the stock solution is metered into the saturator by a diaphragm dosing pump to avoid localised pH swings that can precipitate magnesium hydroxide above pH 11.5.
Alkaline hydrogen peroxide brightening of softwood TMP and stone groundwood at 20–35% stock consistency in high-consistency towers is limited by manganese-catalysed peroxide decomposition during the first 10 min after chemical addition. Manganese is introduced by the wood furnish at 30–120 mg/kg oven-dry pulp in some spruce and pine species; at these concentrations, the unchelated metal accelerates peroxide breakdown before alkali has fully swollen the fibre wall and produced measurable ISO 2470-1 brightness gain. EDTA MgNa2 is dosed at 0.05–0.2 wt% on oven-dry pulp at the peroxide mixing screw upstream of the high-consistency tower, where pH is maintained at 10.5–11.2 and temperature at 60–85°C for 60–120 min. The compound exchanges Mg(II) for Mn(II) and Fe(III) in the chelate structure, as the stability constants in Table 1 indicate; this exchange immobilises the redox-active metal and permits the peroxide residual after 30 min to be maintained above 40% for continued brightening. Brightness pads are measured after pressing and conditioning at 23°C and 50% RH according to ISO 187; residual peroxide is determined by iodometric titration of tower discharge at 10-min intervals. In twin-wire press washing after the tower, the dissolved EDTA complexes carry the chelated metals into the filtrate; removal of this filtrate reduces re-deposition of manganese onto fibres when the pulp is thickened on a vacuum drum washer. Overdosing above 0.3 wt% produces no additional brightness advantage and increases COD load in mill effluent, which is monitored by ISO 6060; published data for a MgNa2-specific threshold in high-yield pulp is limited, so mills run a dose-response trial on their specific furnish rather than relying on generic chelant equivalency.
| Metal ion | log K |
|---|---|
| Mg(II) | 8.69 |
| Ca(II) | 10.65 |
| Mn(II) | 13.87 |
| Fe(II) | 14.27 |
| Zn(II) | 16.50 |
| Cu(II) | 18.80 |
| Fe(III) | 25.10 |
Without a chelation stage upstream of the neutralisation step, a multi-port liquid laundry detergent compounding line operating with 5–10 wt% hydrogen peroxide as an oxygen-based stain remover experiences progressive transmittance loss and off-gassing during storage at 40°C when trace Fe and Cu from caustic soda, sodium silicate, and process water are not sequestered. EDTA MgNa2 is metered as a 20–30% aqueous solution into the batch at 0.05–0.8 wt% of the final formula, depending on the heavy-metal load measured by inductively coupled plasma mass spectrometry before the neutralisation step. The compound is added before silicate and peroxide so that the sequestrant is fully dissolved at pH 8.5–9.5, avoiding precipitation of magnesium hydroxide that occurs above pH 10.5 when the neutralisation front is too rapid. Storage stability is evaluated in closed polyethylene terephthalate bottles at 40°C and 75% RH for 4 weeks; dissolved oxygen headspace pressure and peroxide retention are compared with a control formulation containing no chelant. A drop in hydrogen peroxide below 80% of the initial assay, measured by AATCC TM 102, indicates that the chelant dose must be increased or that copper contamination exceeds 0.5 mg/kg, for which published formulation guidance often recommends a combination of EDTA and phosphonate stabilisers. The MgNa2 salt is selected in low-sodium detergent architectures where every 1 wt% of the compound contributes approximately 0.13 wt% sodium based on the anhydrous molar mass of 358.5 g/mol, compared with fully sodium-neutralised EDTA salts; this ion-load difference is relevant when formulators must stay below a total sodium declaration of 2.0 wt% in concentrated liquid products. Enzyme compatibility is checked by protease activity retention after 2-week storage at 35°C, because the chelant can strip calcium from subtilisin-type protease stabilisation sites, especially above 0.5 wt% in formulations with low free calcium.
In zinc-phosphate pre-treatment lines for stamped steel and hot-dip galvanized automotive body components, alkaline soak cleaners operate at 55–65°C for 3–5 min immersion with 3–5 wt% caustic soda, 0.5–2 wt% sodium metasilicate, 0.2–1.0 wt% nonionic surfactants, and 0.1–0.5 wt% EDTA MgNa2 based on total bath volume. The chelant controls Fe(III) derived from steel fines and excess calcium/magnesium hardness carried from city water; without chelation, brown Fe(OH)3 floc deposits on metal surfaces and reduces zinc-phosphate crystal count per unit area, measured by scanning electron microscopy at 500× magnification. With 0.3 wt% EDTA MgNa2, the cleaner bath remains free of visible sludge for an 8-hour production shift at a throughput of 1,200 m² of substrate per hour; sludge accumulation is monitored by gravimetric filtration of a 100 mL bath sample through a 0.45 µm membrane. Free alkalinity is maintained by automatic titration according to ISO 9963-2, and chelant concentration is checked by potentiometric titration with Fe(III) standard using a platinum redox electrode, because an excess of free chelant in the rinses can interfere with subsequent zinc-phosphate coating weight. Phosphate coating mass is measured by gravimetric stripping according to ISO 3892, and paint adhesion after e-coat is evaluated by cross-cut per ISO 2409; if the first rinse water hardness exceeds 200 mg/L CaCO3, a rinse-stage dose of 0.2–0.4 wt% prevents scale on spray nozzles. The product is incompatible with acid displacement cleaners below pH 2.0 due to precipitation of EDTA acid, and it should not be pre-mixed with concentrated cationic polymer demulsifiers, which can form insoluble coacervates at pH 7–9.
Open recirculating cooling water systems supplied with high-bicarbonate well water at 300–600 mg/L CaCO3 alkalinity and 0.5–2.0 mg/L total iron experience iron oxide deposition when phosphonate and polyacrylate inhibitors are overwhelmed by soluble iron in the return loop. EDTA MgNa2 is injected into the makeup water at 5–20 mg/L as active product, upstream of the biocide feed, to sequester Fe(II) and Fe(III) before oxidation raises the pH above 8.5 and forms hematite particulates. The free ligand releases Mg(II) upon binding Fe(III) due to the log K differential of 25.10 versus 8.69, and remains active only in mild reducing environments; continuous chlorination should keep free chlorine below 0.2 mg/L because hypochlorous acid degrades aminocarboxylate chelants and releases previously bound iron. Corrosion inhibition is monitored with carbon steel coupons according to ASTM G1, and deposition is monitored with a heated test section maintained at 60°C skin temperature; the difference between bulk water iron and filtered iron measured by 0.45 µm membrane filtration indicates particulate iron load. Cycles of concentration are maintained by conductivity control at 3,000–4,000 µS/cm; the chelant requirement is recalculated after every conductivity setpoint increase because free sequestrant is consumed by both hardness and heavy metals. In systems with calcium above 800 mg/L CaCO3, EDTA MgNa2 should not be used as the sole scale inhibitor, because Mg(II) displaced from the chelate can form magnesium silicate sludge if soluble silica exceeds 150 mg/L and pH exceeds 9.0; published data for this specific threshold configuration is limited, so treatment trials should include a side-stream pilot loop before full-system application.
| Application segment | Test or compliance standard |
|---|---|
| Textile bleaching | AATCC TM 102; ASTM D5035; ISO 11885 |
| Pulp brightening | ISO 2470-1; ISO 187; ISO 6060 |
| Metal pre-treatment | ISO 9963-2; ISO 3892; ISO 2409 |
| Cooling water | ASTM G1; ISO 9963-2 |
| Foliar nutrition | AOAC 983.09; Regulation (EU) 2019/1009 |
In fertigated vegetable crops and orchard foliar programmes, magnesium supplied as EDTA MgNa2 is used to avoid precipitation of magnesium hydroxide or magnesium carbonate when the water source contains 200–500 mg/L HCO3−. The application rate is commonly 0.1–0.5 kg/ha per event, dissolved in 500–1,000 L/ha water, with tank pH adjusted to 5.5–6.5 using a non-nitrogen buffer because alkaline pH hydrolyses the chelate and releases free Mg(II), which then precipitates. The sprayed solution is applied through flat-fan hydraulic nozzles at 2–3 bar and 150–250 L/ha; field verification of leaf magnesium is performed on dried leaf tissue by acid digestion and atomic absorption spectrophotometry according to AOAC 983.09. The formulation should not be combined with concentrated calcium nitrate or liquid phosphate fertilizers unless a jar test at 25°C in a 1 L beaker demonstrates no visible precipitate after 30 min; at pH above 7, calcium competes with Mg for the ligand and can displace magnesium from the chelate, reducing the magnesium dose available to the leaf surface. For EU marketing, fertilising products containing EDTA chelates must meet the requirements of Regulation (EU) 2019/1009, including declaration of water-soluble magnesium content and verification of chelated fraction stability across the declared pH range. Overhead irrigation compatibility is checked by measuring solution clarity after 24 h static storage in black polyethylene tanks; published field response data for this specific chelate is limited, and efficacy is typically established through strip trials with leaf tissue analysis rather than through generic micronutrient replacement tables.
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Magnesium disodium ethylenediaminetetraacetic acid (EDTA MgNa2) is distributed under CAS registry number 14402-88-1 and EINECS registry number 238-372-3. The anhydrous molecular formula is C10H12MgN2Na2O8, with a theoretical molecular weight of 358.50 g/mol. On an anhydrous basis, the molecule contains 6.78% w/w magnesium and 12.82% w/w sodium. Commercial specifications are normally expressed by assay, metal content, pH, loss on drying, and particle-size residue rather than by a harmonized model code. The product is supplied as a white to off-white crystalline powder with an assay of 98.0–101.0% w/w on the dry basis. The tetraanionic EDTA ligand coordinates the magnesium(II) centre through two amine nitrogen atoms and four carboxylate oxygen atoms, forming a distorted octahedral complex; the two sodium ions remain as counterions. This structure is responsible for the absence of free sulfate and chloride counterions in solution.
| Parameter | Specification or typical value | Analytical method |
|---|---|---|
| CAS registry number | 14402-88-1 | — |
| Molecular formula | C10H12MgN2Na2O8 | — |
| Molecular weight | 358.50 g/mol | — |
| Assay, dry basis | 98.0–101.0% w/w | Complexometric titration with 0.1 M zinc sulfate |
| Magnesium content | 6.0–7.0% w/w | ICP-OES per ISO 11885 |
| Sodium content | 12.0–12.8% w/w | ICP-OES per ISO 11885 |
| pH, 1% w/w solution at 25 °C | 6.5–7.5 | ISO 10523 |
| Loss on drying at 105 °C | ≤1.0% w/w | ISO 787-2 |
| Chloride as Cl | ≤0.05% w/w | ISO 10304-1 |
| Sulfate as SO4 | ≤0.1% w/w | ISO 10304-1 |
| Heavy metals as Pb | ≤10 mg/kg | ISO 17294-2 via ICP-MS |
| Arsenic | ≤3 mg/kg | ISO 17294-2 via ICP-MS |
| Particle size, residue on 80 mesh | ≤5% | Dry sieve using ISO 3310-1 sieves |
Routine analytical verification for a technical-grade lot includes complexometric titration against 0.1 M zinc sulfate at pH 10 using eriochrome black T or xylenol orange indicator. Because the titration does not differentiate magnesium bound to EDTA from free magnesium ions, a separate ICP-OES measurement according to ISO 11885 is used to confirm total magnesium content. Sodium content is also measured by ICP-OES, and heavy-metal residues are determined by ICP-MS according to ISO 17294-2. In cases where the material is intended for use in closed-loop fertigation, the free-ion fraction should be reported because the chelation capacity of a formulation is not equal to the total magnesium present. The analytical tolerance between titration and ICP-OES for magnesium is generally held within ±0.2 percentage points.
Published data for the exact saturation solubility of the anhydrous crystalline material under defined relative humidity is limited; most supplier literature reports only that the material is freely soluble in water at 20 °C without a defined saturation limit. In practice, 5–10% w/w stock solutions are routinely prepared by metering the powder through an eductor funnel into a stirred polypropylene tank. Production-scale dissolution follows a wetting-first sequence. A high-shear rotor–stator disperser operating at tip speeds of 3–5 m/s is used for 10% w/w stock batches; static batch mixing without an eductor may produce undissolved fines that require an additional 30–60 min hold at 20 °C. Packaging is typically 25 kg net weight in polyethylene-lined fibre drums or 500 kg bulk bags. Storage below 40 °C and 60% RH is specified; exposure above 60% RH can produce surface caking, and re-sieving through a 500 µm screen is recommended before use. Under these conditions, the product is typically assigned a shelf life of 24 months from the date of manufacture.
The operational pH window is governed by two competing reactions: protonation of the carboxylate groups below pH 4.0 and metal exchange with higher-affinity cations above neutral pH. The formation constant of the Mg–EDTA complex is reported as log K = 8.79 at 20 °C and 0.1 M ionic strength. The corresponding calcium complex has log K = 10.65, and iron(III)–EDTA has log K = 25.1. In a concentrated stock solution containing free calcium from calcium nitrate or hard water, calcium(II) can displace magnesium from the ligand. The exchange is thermodynamically favoured, although the rate is slow at 20 °C. At elevated stock-tank temperatures above 35 °C, the displacement reaction accelerates sufficiently to alter magnesium availability within a single batch hold. The displaced magnesium is then limited by secondary precipitation with phosphate or carbonate alkalinity when solution pH exceeds 7.0.
Concentrated stock solutions should not be blended with calcium nitrate, ammonium phosphate, or sulfate-bearing fertilizers at the same tank concentration. If combined in dilute irrigation water, total calcium should be kept below the gypsum saturation threshold of 2.4 g/L at 25 °C, and the solution pH should be maintained between 5.5 and 6.8. These limits are derived from solubility equilibria rather than from chelate decomposition; the EDTA ligand itself remains intact under normal storage conditions below 40 °C.
Magnesium disodium EDTA also functions in alkaline aqueous cleaning and descaling formulations where a pH-neutral chelate is required and where free magnesium hydroxide would otherwise precipitate above pH 9.5. The compound reduces scale nucleation without introducing the sodium-based alkalinity that would shift cleaner pH above 11. In stainless steel circulating systems, formulations containing the chelate can be evaluated for pitting resistance according to ASTM G46; this is particularly relevant when chloride-bearing water is used for dilution. The absence of sulfate in the molecule also prevents calcium sulfate scale formation when the cleaning solution is reused in hard-water circuits.
For drip-fertigation, the delivered magnesium dose is set by the injection ratio of the dosing pump and the crop demand. A diaphragm metering pump with a turndown ratio of 10:1 and a 1:100 injection ratio will produce a line concentration of 5 mg/L magnesium when the stock solution contains 0.5 g/L of product at 6.78% w/w magnesium. This calculation assumes a homogeneous stock and does not account for in-line dilution from acid or additional fertilizers. The solution should be checked with an inline pH sensor calibrated to ISO 10523; target irrigation water pH is 5.5–6.8 to retain bicarbonate below 120 mg/L alkalinity, above which calcium carbonate scaling can occur on emitters. Foliar sprays generally use 0.1–0.3% w/w product concentration with non-ionic surfactant at 0.025–0.05% v/v; droplet size is maintained above 150 µm volume median diameter to reduce drift.
Compared with magnesium sulfate heptahydrate, EDTA MgNa2 has a lower magnesium content per unit mass but remains soluble in phosphate-containing formulations. At pH 7.5, free Mg²⁺ from sulfate at 100 mg/L will begin to precipitate with 100 mg/L phosphate, whereas the same total magnesium supplied as the EDTA chelate remains in solution for at least 48 h at 20 °C. Published data for this specific multi-anion combination is limited to formulator-generated stability logs rather than peer-reviewed standard test methods.
In a mixed-cation environment, the utility of EDTA MgNa2 depends on the thermodynamic preference of the ligand. Because calcium(II) has a larger formation constant than magnesium(II), the product is not a suitable magnesium source in high-calcium brines unless the calcium is first removed or complexed by a second chelant. Conversely, iron(III) has a formation constant of 25.1, so ferric salts in the same tank will rapidly degrade the magnesium chelate by metal exchange, producing iron–EDTA and free magnesium. The release of magnesium in phosphate-containing formulations can then form magnesium ammonium phosphate at pH above 6.5, fouling injectors and drip emitters. Operational boundaries therefore exclude simultaneous use of ferric chloride, ferric sulfate, or acid mine drainage water without pre-treatment.
| Product | Typical metal content | Log K for chelated metal | pH of 1% solution | Primary role | Typical limitation |
|---|---|---|---|---|---|
| EDTA MgNa2 | 6.0–7.0% w/w Mg | 8.79 | 6.5–7.5 | Pre-chelated magnesium source | Metal exchange with Ca²⁺ and Fe³⁺ |
| Disodium EDTA | No chelated metal | — | 4.0–5.0 | Calcium sequestrant | Acidic pH; no magnesium contribution |
| Calcium disodium EDTA | 10.6–11.1% w/w Ca | 10.65 | 6.5–8.0 | Pre-chelated calcium source | Not a magnesium source |
| Tetrasodium EDTA | No chelated metal | — | 10.0–11.0 | Alkaline chelant | High pH shift; no magnesium contribution |
| Magnesium sulfate heptahydrate | 9.86% w/w Mg | None | 5.0–7.0 | Readily soluble magnesium salt | Precipitates with phosphate and carbonate |
The comparison shows that EDTA MgNa2 occupies a specific formulation niche. It supplies magnesium in a form that resists precipitation with phosphate and carbonate at pH below 7.0, but it does not provide the free-calcium sequestering capacity of disodium or tetrasodium EDTA. The product should not be substituted for a free magnesium salt when rapid ion uptake is the primary requirement, because the chelated metal must be released from the ligand before it becomes available for ion-exchange processes.
Regulatory classification of the salt differs from food-approved calcium disodium EDTA. Under EU 231/2012, the specifications for food additives include calcium disodium EDTA as E385; magnesium disodium EDTA is not automatically covered by that monograph and must be verified against the positive list for the intended use. For technical applications, REACH registration under EC 1907/2006 applies when the annual manufactured or imported quantity exceeds 1 tonne per legal entity. The safety data sheet should state whether the substance has a harmonised CLP classification under EC 1272/2008; for this grade, no acute toxicity classification is generally assigned, but dust exposure control is recommended to keep respirable particulates below 3 mg/m³ as an 8-hour time-weighted average.
Analytical verification of the chelate in formulated products is performed by ion chromatography for the EDTA ligand and by ICP-OES for magnesium after acid digestion. When testing mixed fertilizer blends, the free magnesium fraction should be determined separately because complexometric titration alone overestimates the chelated fraction in the presence of other aminopolycarboxylates. A practical limit for routine quality control is ±0.2 percentage point agreement between ICP-OES and titration for magnesium content; larger deviations indicate incomplete digestion or the presence of free magnesium oxide. The product should not be combined with strong oxidizing agents or formulated into systems below pH 2.0, because protonation of the carboxylate groups reduces the effective chelating capacity and can promote ligand dissociation under acidic process conditions.
