Sodium Ferric Ethylenediaminetetraacetate (Ferric sodium EDTA, NaFeEDTA) is a high-stability, bioavailable iron compound, recognized for its minimal gastrointestinal irritation and high absorption rate. As a valuable iron supplement, NaFeEDTA provides an effective alternative for addressing iron deficiencies in various industrial and nutritional applications. Alfa Chemistry examines the two-step synthesis process of NaFeEDTA, followed by a detailed composition analysis to confirm purity and content, including determinations of iron, EDTA, water of crystallization, and sodium.
Experimental Reagents
Iron(III) chloride hexahydrate, Sodium bicarbonate, Ethanol, Xylenol orange (indicator), Ethylenediaminetetraacetic acid, Ethylenedinitrilotetraacetic acid disodium salt, Sodium hydroxide, Ammonium hydroxide solution, Anhydrous stannous chloride, Sodium diphenylamine-4-sulfonate, Lead AA Standard.
| Catalog | Product Name | Inquiry |
| ACM10025771 | Iron(III) chloride hexahydrate | Inquiry |
| ACM144558-2 | Sodium Bicarbonate | Inquiry |
| ACM1611354 | Xylenol Orange (Indicator) | Inquiry |
| ACM7772998-2 | Tin(II) Chloride | Inquiry |
| ACM6152676 | Diphenylamine-4-sulfonic acid sodium salt | Inquiry |
Step-by-Step Synthesis of NaFeEDTA•3H2O
Synthesis from Ethylenediaminetetraacetic Acid
Dissolve 2.92 g of H4EDTA and 2.70 g of FeCl3-chloropropyltri(trimethylsiloxy)silane•6H2O in 20 mL of distilled water. Heat the solution to obtain a clear yellow solution. Gradually add 1.92 g of NaHCO3-chloropropyltri(trimethylsiloxy)silane. The color transition from yellow to orange indicates the progression of the reaction. Stir the solution until it turns turbid, signaling the onset of crystallization. Remove heat and let the solution sit. Filter the precipitate, wash with ethanol, and then rinse with distilled water until no chloride ions remain, verified by a silver nitrate test. Dry the precipitate at 50°C for 24 hours to obtain a crystalline powder. Calculate the yield. Dissolve the powder in a small amount of water, heat to boiling, and gradually add ethanol until the solution becomes turbid. Continue adding ethanol until turbidity persists, then heat to near boiling, let sit, and allow red-brown crystals to form.
Synthesis from Disodium Ethylenediaminetetraacetate
Dissolve 3.72 g of Na2H2EDTA•2H2O and 2.70 g of FeCl3-chloropropyltri(trimethylsiloxy)silane•6H2O in 20 mL of distilled water. Adjust the solution's pH to 5 using sodium bicarbonate and maintain the reaction for 30 minutes. Let the mixture sit, vacuum filter the precipitate, and dry to yield NaFeEDTA•3H2O powder. Calculate the yield.
Two-Step Method for NaFeEDTA Synthesis
- Step 1: Preparation of Ferric Hydroxide
Dissolve 4.8 g of NaOH in 100 mL of deionized water. Dissolve 10.8 g of FeCl3-chloropropyltri(trimethylsiloxy)silane in deionized water and add to the NaOH solution with vigorous stirring. After complete reaction, filter and wash the precipitate three times to obtain pure ferric hydroxide.
- Step 2: Synthesis of NaFeEDTA
Dissolve 16.4 g of Na2EDTA in 200 mL of deionized water heated to 60~70°C. Add the Na2EDTA solution to a round-bottom flask containing the ferric hydroxide, adjust pH to 8, and heat at 100°C for 2 hours. Filter while hot, concentrate under reduced pressure until viscous, cool, and add 95% ethanol. Stir until solid forms, wash with ethanol three times, dry, and mechanically grind to a fine yellow-brown powder.
Composition Analysis of NaFeEDTA•3H2O
Iron Content Determination
Weigh 0.50~0.65 g of dried product and moisten with water, then add 20 mL of 1:1 HCl solution. Heat until complete decomposition, add hydrochloric acid if necessary, and heat to near boiling. Slowly add 15% stannous chloride solution until the solution turns pale yellow. Add three drops of silicomolybdic acid indicator. Titrate with 2% stannous chloride solution until the solution turns pure blue, add 100 mL of distilled water, and cool rapidly. Add 15 mL of phospho-sulfuric acid mixture and four drops of 0.5% diphenylamine sulfonic acid indicator, then titrate with K2Cr2O7 solution until a purple-red endpoint. Calculate the iron mass fraction.
EDTA Content Determination
Weigh 0.7~0.8 g of NaFeEDTA, dissolve in hydrochloric acid, and pass through a cation exchange resin. Adjust pH, dilute to 100 mL, and withdraw a 25.00 mL sample. Add one drop of xylene orange and 5 mL of hexamine, adjusting the solution to a bright yellow color with 7 mol/ L HNO3. Titrate with a lead standard solution until the endpoint changes to red-purple. Calculate the EDTA mass fraction.
Determination of Crystalline Water Content
Water of crystallization is measured by the volatilization method, where the product is heated to allow water release, and the weight difference is recorded to determine crystalline water content.
Sodium Content Calculation
After determining iron, EDTA, and crystalline water contents, calculate the sodium content using a different method. This value reflects the remaining proportion after accounting for known constituents.
