E-mail: sales001@bosschemical.com JINAN BOSS CHEM CO.,LTD
Telephone: +86-15628782329
- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Views: 0 Author: Site Editor Publish Time: 2026-08-06 Origin: Site
Sodium Phosphate Dibasic (also known as Disodium Phosphate, Disodium Hydrogen Phosphate, or simply DSP) is an inorganic compound with the chemical formula Na₂HPO₄. It exists in three principal hydration states — anhydrous (Na₂HPO₄), dihydrate (Na₂HPO₄·2H₂O), and dodecahydrate (Na₂HPO₄·12H₂O) — each tailored to different industrial requirements.
As one of the three fundamental sodium phosphates — alongside Monosodium Phosphate (MSP, NaH₂PO₄) and Trisodium Phosphate (TSP, Na₃PO₄) — DSP occupies a unique position in the phosphate family. Its dibasic nature gives it exceptional buffering capacity in the pH 7–9 range, making it the go-to choice for applications requiring mildly alkaline pH control.
In the food industry, DSP is designated as E339(ii) under the European food additive numbering system and is Generally Recognized as Safe (GRAS) by the U.S. FDA.
Understanding DSP's physicochemical profile is essential for proper application across industries.
Property | Anhydrous (Na₂HPO₄) | Dihydrate (Na₂HPO₄·2H₂O) | Dodecahydrate (Na₂HPO₄·12H₂O) |
Molecular Weight | 141.96 g/mol | 177.99 g/mol | 358.14 g/mol |
P₂O₅ Content | ~49.8% | ~39.8% | ~19.8% |
Melting Point | ~250°C (decomposes) | ~92.5°C (loses water) | ~35°C (melts in own water of crystallization) |
Density | ~1.68 g/cm³ | ~2.07 g/cm³ | ~1.52 g/cm³ |
Water Solubility (20°C) | ~77 g/L | ~93 g/L | ~220 g/L |
pH (1% aq. solution) | 8.5–9.5 | 8.5–9.5 | 8.5–9.5 |
Bulk Density | 0.8–1.1 g/cm³ | 0.9–1.1 g/cm³ | 0.7–1.0 g/cm³ |
DSP is one of the most widely used phosphate additives in food processing, where it serves multiple functional roles:
Function | Application Examples |
Emulsifier | Processed cheese, cheese spreads, evaporated milk — prevents fat separation and ensures smooth texture |
pH Buffer / Acidity Regulator | Baked goods, instant puddings, sauces — stabilizes pH during processing and shelf life |
Leavening Agent | Pancake mixes, cake premixes, self-rising flour — reacts with sodium bicarbonate for controlled CO₂ release |
Moisture Retention | Processed meat, poultry, seafood — improves water-holding capacity and yield |
Sequestrant | Canned vegetables, fruit fillings — binds metal ions to prevent discoloration and off-flavors |
Nutrient Fortification | Sports drinks, nutritional beverages — provides bioavailable phosphorus |
In municipal and industrial water treatment systems, DSP serves as:
Corrosion inhibitor:
● Forms a protective phosphate film on metal pipe surfaces, reducing corrosion rates in distribution networks by up to 70–90%.
Scale prevention:
● Sequesters calcium and magnesium ions, preventing scale formation in boilers, cooling towers, and heat exchangers.
pH buffer:
● Maintains stable pH in closed-loop recirculating water systems, critical for optimizing other treatment chemicals.
Typical dosage in potable water treatment ranges from 0.5–3.0 mg/L as PO₄.
DSP has been used in textile processing for over a century due to its unique properties:
Mordant in dyeing:
● Acts as a fixing agent that binds dyes to natural fibers (cotton, wool, silk), improving colorfastness and wash resistance.
Silk weighting:
● Traditionally used to add weight and body to silk fabrics after degumming, giving silk its characteristic drape and sheen.
pH control in dye baths:
● Buffers dye solutions to the optimal pH for reactive and vat dyes, ensuring consistent color uptake.
Flame retardant treatment:
● Combined with other phosphates in finishing baths to impart flame-resistant properties to cotton and blended fabrics.
In ceramic and glass production, DSP contributes to:
Deflocculant in ceramic slips:
● Reduces water demand in clay suspensions, enabling higher solids loading and lower energy consumption during spray drying. Typical addition: 0.1–0.5% by dry weight.
Flux in glass batches:
● Lowers the melting temperature of glass formulations, reducing furnace energy consumption and improving melt homogeneity.
Enamel frits:
● Incorporated into porcelain enamel formulations to control viscosity and improve adhesion to metal substrates.
DSP is a source of both phosphorus (P) and sodium (Na) in agricultural applications:
Water-soluble phosphate fertilizer:
● Suitable for fertigation and foliar spray systems where rapid nutrient availability is required. Typical P₂O₅ content: ~50% (anhydrous).
pH buffering in hydroponic solutions:
● Maintains optimal nutrient solution pH (5.8–6.5) in controlled-environment agriculture.
Animal feed additive:
● Serves as a dietary phosphorus supplement in livestock and poultry feed formulations (non-pharmaceutical nutritional use).
Heavy-duty alkaline cleaners:
● DSP provides alkalinity and buffering in industrial degreasers, CIP (Clean-in-Place) solutions, and metal parts washers.
Sequestration builder:
● Softens water by binding calcium and magnesium ions, enhancing surfactant effectiveness in hard water conditions.
Metal surface treatment:
● Used in phosphating baths to prepare steel surfaces for painting or powder coating.
Understanding the differences between the three primary sodium phosphates is critical for selecting the right product for your application:
Parameter | Monosodium Phosphate (MSP) | Disodium Phosphate (DSP) | Trisodium Phosphate (TSP) |
Formula | NaH₂PO₄ | Na₂HPO₄ | Na₃PO₄ |
pH (1% solution) | 4.2–4.6 (acidic) | 8.5–9.5 (mildly alkaline) | 11.5–12.5 (strongly alkaline) |
P₂O₅ Content | ~59% (anhydrous) | ~50% (anhydrous) | ~43% (anhydrous) |
Buffering Range | pH 2.0–4.5 | pH 6.0–8.5 | pH 11.0–12.5 |
Primary Use | Acidulant, metal treatment, cheese emulsifier | Food buffer, water treatment, textile mordant | Heavy-duty cleaner, degreaser, paint stripper |
Food Additive Code | E339(i) | E339(ii) | E339(iii) |
Solubility | Very high | High | Moderate |
