| HS Code | 757675 |
| Productname | DTPA 5Na |
| Chemicalname | Pentasodium diethylenetriaminepentaacetate |
| Synonyms | Pentasodium DTPA; DTPA pentasodium salt; Diethylenetriaminepentaacetic acid pentasodium salt |
| Casnumber | 140-01-2 |
| Einecscode | 205-391-3 |
| Molecularformula | C14H18N3Na5O10 |
| Molecularweight | 503.25 g/mol |
| Chemicalclass | Aminopolycarboxylate chelating agent |
| Appearance | White to off-white crystalline powder or colorless to pale yellow aqueous solution |
| Physicalstate | Solid or liquid (aqueous solution) |
| Odor | Odorless |
| Solubilityinwater | Highly soluble |
| Solubilityinorganicsolvents | Insoluble |
| Ph | 11.0-12.0 (1% aqueous solution) |
| Chelatingproperty | Strong chelating agent; forms stable complexes with metal ions |
| Stability | Stable under normal storage conditions; hygroscopic |
| Storageconditions | Store in a cool, dry, well-ventilated area in a tightly closed container |
| Assay | Typically 40% aqueous solution or >= 98% solid |
As an accredited DTPA 5Na factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | DTPA 5Na is supplied in 25 kg polyethylene-lined, moisture-barrier paper sacks and 1000 kg bulk bags. |
| Container Loading (20′ FCL) | DTPA 5Na loaded in a 20′ FCL container, palletized, shrink-wrapped, securely braced, and sealed for ocean export. |
| Shipping | DTPA 5Na (pentasodium diethylenetriaminepentaacetate) is generally shipped as non-hazardous, non-DG cargo. It normally requires no UN number, hazard class, or packing group. Use sealed, labeled containers; protect from moisture, extreme heat, and incompatible oxidizers. For solutions, verify concentration and pH; some formulations may be regulated. Follow applicable transport regulations. |
| Storage | Store DTPA 5Na in a cool, dry, well-ventilated area in a tightly closed original container. Protect from moisture, heat, direct sunlight, and contamination. Keep separate from strong acids, oxidizers, and food or feed. Avoid dust generation and inhalation. Maintain good housekeeping; use secondary containment where appropriate. Store only in labeled containers. Follow local regulations and SDS requirements. |
| Shelf Life | Shelf life: about 24 months when stored sealed, cool, dry, in original packaging, protected from moisture, heat, direct sunlight. |
Pentasodium diethylenetriaminepentaacetate (DTPA 5Na, CAS 140-01-2) is delivered as a 40% w/w aqueous solution in phosphate-free automatic dishwasher detergent production. The solution is introduced into the premix vessel before addition of sodium carbonate and sodium percarbonate. The addition rate in finished powder is held between 0.4 wt% and 2.5 wt% active solids, while liquid light-duty formulations typically use 0.05 wt% to 0.3 wt% of the solution as a trace-metal control agent. EC 648/2004 governs ingredient-level classification and labelling in detergent systems, and REACH Regulation (EC) No 1907/2006 covers registration and supply-chain communication in the European market. In spray-drying lines, DTPA 5Na is blended with nonionic surfactants and alkali at 55–65 °C before atomization, which prevents localized precipitation of calcium-DTPA chelates at high solids. In liquid laundry detergent production, the chelator is added after neutralization of alkylbenzene sulfonic acid at pH 9.0–10.5; dosing ahead of the neutralization loop can produce temporary free acid speciation and heat release. Production-scale observations show that feed-water hardness differences of 200–350 ppm CaCO₃ require dosage adjustments of 0.05–0.1 wt% to maintain peroxide residuals in oxygen bleach powder stability. Terminal products include phosphate-free machine dishwashing tablets, oxygen bleach-containing universal laundry powders, industrial CIP cleaner concentrates, and destaining sachets.
Hydrogen peroxide brightening of thermomechanical pulp (TMP) uses DTPA 5Na as a chelation-stage additive before the peroxide tower. The addition rate on oven-dry pulp ranges from 0.3 kg/t to 2.5 kg/t in the Q stage, with the upper end required for softwood chips carrying elevated manganese burden. Compliance for finished food-contact board is assessed under FDA 21 CFR 176.170 and EN 648:2006 migration testing, while process emissions are managed within the EU pulp and paper BAT reference document. The downstream process operates at 10–14% consistency with retention time 45–120 min, pH 10.5–11.5, and temperature 60–80 °C; the chelator is injected into the medium-consistency transfer line upstream of the steam mixer. A critical process conflict occurs when the Q-stage drops below pH 4.5, because the pentasodium salt can revert to the acid form and precipitate; the stage is therefore maintained at pH 5–6 before alkali addition. In TMP mills, DTPA 5Na is commonly combined with or used as partial replacement for sodium silicate, reducing silicate deposition on downstream evaporators and heat exchangers. Terminal product types include newsprint, supercalendered light weight coated papers, tissue, and folding boxboard.
Continuous pad-steam bleaching of cotton and polyester/cotton blends requires iron control within the peroxide bath, where dissolved Fe(III) concentrations above 0.5 ppm in process water can generate localized oxygen release. DTPA 5Na is added at 0.1–0.5 g/L of the bleaching liquor, as a 40% w/w solution; the optimum is determined by titration of raw water hardness and ferric ion. ZDHC MRSL v2.0 does not list DTPA 5Na under restricted substances, and finished textiles are assessed for extractable heavy metals under OEKO-TEX Standard 100. The operation is a pad-steam sequence: fabric is padded with a solution containing hydrogen peroxide (20–40 mL/L at 50% w/w), sodium hydroxide (10–30 g/L), wetting agent, and DTPA 5Na, then steamed at 100–102 °C for 20–40 min. Adding DTPA 5Na directly to the concentrated peroxide storage drum is avoided because localized heat generation can trigger accelerated peroxide decomposition; it is injected into the diluting water line prior to the pad trough. Terminal product types include desized and bleached cotton twill, knitted cotton jersey for reactive dyeing, and polyester/cotton medical workwear fabrics.
Reverse osmosis trains receiving groundwater with ferrous iron below 0.5 mg/L can still lose permeate flux when iron oxidizes to Fe(OH)₃ in the concentrate. DTPA 5Na is injected at 1–10 mg/L as active compound upstream of the cartridge filter through a diaphragm metering pump and static mixer; the dosage is set by feed iron concentration and pH. The reported Fe(III) stability constant is log K 28.6, while Ca(II) log K is 10.8 under standard conditions, giving selective iron chelation in the pH 6.5–8.5 range typical of RO feed water. NSF/ANSI/CAN 60 certification is required for potable water treatment chemicals in North America, and finished water quality is assessed under Directive (EU) 2020/2184 where the permeate is intended for drinking water supply. The product is diluted to 1–5 wt% with demineralized water before injection to avoid plunger seal damage in the metering pump from the high-pH concentrate. A documented operational boundary is oxidative degradation by free chlorine and hypochlorite; the injection point is therefore placed upstream of the reducing agent or after dechlorination in municipal RO systems. Terminal product categories include boiler make-up water, cooling tower make-up, pharmaceutical purified water feed, and high-pressure steam generator influent.
For fertigation-grade iron chelate concentrates, DTPA 5Na is reacted with ferrous sulfate heptahydrate in a heated stirred reactor to produce Fe-DTPA. The addition ratio is stoichiometric at 1.00 mol DTPA per 1.00 mol ferrous iron; an excess of iron above 2% by weight can form free metal hydroxides that plug drip emitters. In the field, Fe-DTPA is applied at 0.5–2.5 kg Fe/ha per growing cycle or injected continuously at 1–5 ppm Fe in hydroponic nutrient solution, and is suitable only in media with pH below 7.5 because Fe-DTPA exchange with calcium can occur at higher pH. The regulatory framework includes EU Fertilising Products Regulation (EU) 2019/1009 for CE-marketed micronutrient fertilizers and AAPFCO official definitions for chelated micronutrient guarantees in the United States. The dissolution process is run at 50–70 °C with pH adjustment to 5.0–6.0 using citric acid or sulfuric acid, and completion is filtered through 25 μm bag filters to remove insoluble residues. Terminal product forms include water-soluble NPK plus micronutrient powders, foliar feed suspensions, drip irrigation concentrates, and hydroponic A/B stock solutions.
Cold-mix shampoo and body wash lines use DTPA 5Na at 0.01–0.20 wt% of the finished formulation, dissolved into the water phase before addition of betaine and anionic surfactants. The INCI designation is Pentasodium Pentetate, and use in rinse-off formulations is evaluated within the cosmetic product safety report under Regulation (EC) No 1223/2009; manufacturing practice is bounded by ISO 22716:2007. Addition is made after initial water acidification to pH 5.5–6.5 because the sodium salt raises pH and can shift surfactant cloud point during blending. The key downstream production parameter is the trace iron content of the water supply; an increase from 0.1 ppm to 0.5 ppm ferric ion can reduce oxidative stability of unsaturated emollients and produce color shift in clear products. In high-shear mixers, DTPA 5Na controls viscosity drift caused by metal-catalyzed oxidation of thickening polymers. Terminal product types include sulfate-free shampoo, syndet bars, micellar body wash, and clear hand cleanser.
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The pentasodium salt of diethylenetriaminepentaacetic acid, DTPA 5Na (CAS 140-01-2), is an octadentate aminopolycarboxylate supplied as either a clear to pale-yellow aqueous concentrate or a white to off-white spray-dried powder. The anhydrous molecular formula C14H18N3Na5O10 corresponds to a molecular weight of 503.25 g/mol. Commercial model codes include DTPA-5Na-40 for the 40% active solution and DTPA-5Na-P for the powder. The product functions primarily as a high-affinity chelating agent for polyvalent metal ions, with the five carboxylate arms and three amine nitrogen donor atoms forming an eight-coordinate geometry that occupies more metal coordination sites than the hexadentate EDTA system.
Typical specification ranges for the two common commercial forms are listed in Table 1. These values represent procurement specification windows; batch-specific certificates of analysis take precedence.
| Parameter | DTPA-5Na-40 | DTPA-5Na-P |
|---|---|---|
| Appearance | Clear to pale-yellow liquid | White to off-white powder |
| Assay as DTPA pentasodium | 39.5–40.5 wt% | 98.0 wt% min on dry basis |
| pH, 1% aqueous solution | 11.0–12.0 | 11.0–12.0 |
| Density at 25 °C | 1.28–1.32 g/cm3 | Not applicable |
| Stoichiometric chelation value | 79–81 mg CaCO3/g | 195–199 mg CaCO3/g |
| Chloride, as Cl | ≤0.05 wt% | ≤0.05 wt% |
| Moisture, Karl Fischer | Not applicable | ≤5.0 wt% |
The chelation stoichiometry is approximately one mole of DTPA 5Na per one mole of CaCO3; the solution-grade figure is therefore lower than the powder-grade figure because of the water matrix. The solution form is typically packaged in 250 kg drums or 1,250 kg intermediate bulk containers, while the powder is packed in 25 kg multi-wall bags. Packaging configuration varies by manufacturer.
The molecular architecture of DTPA 5Na is derived from diethylenetriamine with five carboxymethyl substituents. Complete neutralization with sodium hydroxide yields a readily water-soluble salt with high electrolyte tolerance. The solution remains clear at pH values above 11.0 and is compatible with sodium hydroxide, potassium carbonate, and sodium metasilicate in alkaline cleaning and bleaching formulations. For industrial water treatment and cleaning applications, the product is typically qualified under the supplier’s ISO 9001:2015 quality system. The substance is registered under REACH, and the safety data sheet documents exposure limits, handling precautions, and disposal constraints. The pentasodium salt is not intended for food or pharmaceutical use unless the specific grade is manufactured under applicable pharmacopoeial or food-codex requirements.
In hydrogen peroxide bleaching of mechanical and chemical pulp, transition-metal-catalyzed decomposition of H₂O₂ is the primary process constraint. DTPA 5Na is introduced at 0.05–0.30 wt% on oven-dry pulp ahead of peroxide addition in high-consistency mixer suction or medium-consistency pump suction. The octadentate coordination sphere reduces the availability of labile coordination sites on Fe(III) and Mn(II), suppressing radical generation. The effect is monitored as retained ISO brightness according to ISO 2470-1:2016 and as residual peroxide concentration in the tower discharge.
Representative stability constants at 25 °C and ionic strength 0.1 M are shown in Table 2.
| Metal ion | DTPA 5Na | EDTA | HEDTA | NTA |
|---|---|---|---|---|
| Fe(III) | 28.6 | 25.1 | 19.8 | 15.9 |
| Cu(II) | 21.4 | 18.8 | 17.6 | 13.0 |
| Zn(II) | 18.7 | 16.5 | 14.7 | 10.7 |
| Mn(II) | 17.7 | 13.9 | 10.9 | 7.4 |
| Ca(II) | 10.8 | 10.7 | 8.4 | 6.4 |
| Mg(II) | 9.3 | 8.8 | 7.0 | 5.4 |
The values are thermodynamic formation constants; at process ionic strength and temperature, conditional constants shift by several log units. The important comparison is not the absolute value but the gap between DTPA 5Na and other aminopolycarboxylates for Fe(III) and Mn(II). This gap is the basis for selecting DTPA 5Na when hydrogen peroxide stability is critical and when iron removal by precipitation is not feasible.
At the pH of alkaline peroxide bleaching, typically 10.5–11.5, the conditional stability of the Fe(III)–DTPA complex is higher than that of the corresponding EDTA complex, and the margin widens as temperature increases. Process conditions vary with furnish metal load and tower retention time. In mechanical pulp bleaching, medium-consistency towers are often operated at 85–110 °C with retention of 60–180 min, depending on brightness targets. Iron and manganese concentrations in closed-loop filtrates can range from 0.5 mg/L to 20 mg/L; DTPA 5Na dose is adjusted toward the upper end of the range when manganese exceeds 5 mg/L. Published data for this specific configuration is limited, and the dosage should be confirmed against the furnish metal load.
The operational boundary is set by the calcium and magnesium load. When feed water hardness exceeds 200 mg/L as CaCO3, determined by ASTM D1126-17, a portion of the chelant is consumed by alkaline-earth binding; pre-softening or an increased DTPA 5Na dose is required before peroxide stabilization is observed. The product should not be combined with concentrated hypochlorite or other strong oxidants because oxidative degradation of the amine backbone reduces chelation efficiency.
Metering of DTPA 5Na into the saturator feed at 0.2–0.5 g/L of bath is performed before silicate addition in alkaline peroxide bleaching of cotton and cotton-blend fabrics. Pad-steam conditions typically use 95–100 °C and 15–20 min residence; cold-pad-batch processes use 24 h at ambient temperature. The role of DTPA 5Na is to bind iron released from cotton seed hulls and from corroded equipment surfaces before the metal can catalyze localized fiber tendering. Tensile strength retention is measured according to ISO 13934-1:2013. At equal active dose, DTPA 5Na is selected when the fabric contains high metals due to iron contamination in the caustic and silicate.
DTPA 5Na is used in bottle-washing, dairy-fouling removal, and membrane cleaners where iron oxide co-deposits with calcium carbonate. The product is blended into caustic detergent formulations at 0.1–1.0 wt% as product. Its pentasodium form maintains a high pH, typically 11.0–12.0 for a 1% solution, which supports saponification of fatty soils while the chelant dissolves scale. The chelant demand is calculated from total hardness expressed as CaCO3 under ASTM D1126-17; each kilogram of DTPA-5Na-40 stoichiometrically chelates approximately 80 g of CaCO3. In formulations containing free chlorine, substitution with DTPA 5Na should be avoided because the amine nitrogens are susceptible to oxidation.
Equipment scale removal is typically carried out at 60–80 °C with recirculation through plate heat exchangers or spray bars. The cleaning solution is monitored for pH, iron, and calcium concentration; the end point is usually defined as a plateau in dissolved iron, not by time alone. DTPA 5Na is preferred over EDTA in this duty when the deposit contains Fe₂O₃ along with CaCO₃ because the higher Fe(III) stability constant prevents redeposition of iron hydroxide on stainless steel surfaces. However, if the water hardness exceeds 500 mg/L as CaCO3, the stoichiometric demand may make the treatment uneconomical, and acid predissolution is used before the chelant step.
For cooling water and low-pressure boiler return lines, DTPA 5Na is injected at 5–20 mg/L as DTPA-5Na-40 in the circulating water stream to control iron deposition without forming sludge. The product is typically applied after corrosion inhibitor and dispersant feed, with pH maintained above 8.5. Published data for this specific configuration is limited; dosage is normally adjusted by measuring soluble iron by inductively coupled plasma optical emission spectrometry according to ISO 11885:2007 and total iron by digestion.
The selection between DTPA 5Na and EDTA-4Na depends on the metal speciation and alkalinity of the process stream. DTPA 5Na is preferred when Fe(III) is present above 1 mg/L and pH is above 9.0. The difference arises from the octadentate structure of DTPA versus the hexadentate structure of EDTA; DTPA occupies more coordination sites, reducing the number of coordinated water molecules that can participate in ligand exchange and Fenton-type cycling. For calcium and magnesium sequestration only, EDTA-4Na and DTPA 5Na have similar stability constants, but DTPA 5Na is more effective for iron-specific applications.
Compared with GLDA and MGDA, DTPA 5Na generally provides stronger Fe(III) binding but lower biodegradability. This makes DTPA 5Na suitable for high-temperature or high-alkalinity processes where biodegradable alternatives degrade or lose chelating capacity before disposal. In applications subject to EU Ecolabel or ready-biodegradability restrictions, DTPA 5Na is often replaced by GLDA or MGDA unless the process requires the higher stability constant. NTA has a lower Fe(III) log K of 15.9 and is restricted in some detergent applications, making DTPA 5Na a stronger alternative where regulatory or performance limits exclude NTA.
In oilfield iron-control treatments, DTPA 5Na is applied in acidizing and stimulation fluids at 0.25–1.0 vol% to keep dissolved iron from reprecipitating as ferric hydroxide when the spent acid rises above pH 3.5. Published data for this specific configuration is limited; field formulations are normally qualified by iron turbidity testing at bottomhole temperature and pressure.
