Phosphoric acid(food grade)
Versatile Food Acidulant-Enables precise pH regulation in various food systems including carbonated beverages and dairy products.
High-Purity & Safe-Conforms to rigorous international food-grade specifications (FDA/GB) with minimal heavy metal content.
Effective Sanitizer-Demonstrates efficient cleaning and disinfecting properties for food processing equipment at 10-15% concentration.
Controlled Viscosity-The syrupy consistency of its 85% solution ensures accurate dispensing in industrial food preparation.
Multi-Industry Utility-Extends applications to metal surface treatment, electronics manufacturing, and specialized chemical synthesis processes.
Phosphoric acid (H₃PO₄), referred to as orthophosphoric acid in its pure state, presents as a colorless, viscous liquid or transparent orthorhombic crystalline solid. It is odorless and possesses a characteristically sharp acidic taste. The common commercial form is an 85% aqueous solution, which is a clear, slightly viscous liquid with a syrup-like consistency. The compound has a melting point of 42.35°C and a specific gravity of 1.70. As a non-volatile acid with a high boiling point, it exhibits complete miscibility with water. Upon heating to 213°C, it undergoes partial dehydration to form pyrophosphoric acid, with further heating to approximately 300°C resulting in conversion to metaphosphoric acid. With a relative density of 1.834, it demonstrates ready solubility in both water and ethanol.
Parameter | Value |
Melting Point | 42.35°C (pure) |
Boiling Point | 158°C (decomp.) |
Density (25°C) | 1.834 g/cm³ (pure) |
Viscosity (85%, 25°C) | 147 cP |
pKa Values | pKa₁=2.14, pKa₂=7.20, pKa₃=12.67 |
Refractive Index (85%) | 1.342 |
Thermal Decomposition | → Pyrophosphoric (213°C) → Metaphosphoric (300°C) |
Industrial Applications of Phosphoric Acid
1. Food Industry
Acidulant: Regulates acidity in carbonated beverages at concentrations of 0.05-0.1%
Emulsifier: Facilitates texture control in processed cheese products (0.2-0.4%)
Sanitizer: Effective cleaning agent for dairy processing equipment at 10-15% concentration
2. Agriculture
Fertilizer Production: Key component in phosphate fertilizer manufacturing through reaction with fluorapatite:
Ca5(PO4)3F+5 H2SO4+10 H2O→3 H3PO4+5 CaSO4 ⋅ 2 H2O+HFCaX5(POX4)X3F+5HX2SOX4+10HX2O3HX3POX4+5CaSOX4⋅2HX2O+HF
Soil Amendment: Adjusts soil pH and provides phosphorus nutrition
3. Metal Processing
Surface Treatment: 15-25% solutions for rust removal and iron phosphate coating formation
Metal Phosphating: Creates corrosion-resistant layers on automotive components
Pickling Agent: Prepares metal surfaces for further processing
4. Electronics Manufacturing
Selective Etching: 85% solution achieves high selectivity (>100:1) for silicon nitride versus silicon dioxide
Electrolyte Component: Functions in high-temperature (150°C) fuel cell systems
Surface Preparation: Cleans and treats semiconductor surfaces
5. Chemical Synthesis
Acid Catalyst: Promotes ethylene oligomerization in homogeneous catalytic systems
Dehydration Agent: Facilitates cyclization reactions in organic synthesis
Intermediate Production: Serves as precursor for various phosphate derivatives
Packaging & Storage
Format | Capacity | Material |
Carboys | 30 L | HDPE with tamper-proof cap |
Drums | 250 L | Polyethylene-lined steel |
ISO Tanks | 25,000 L | 316L stainless steel |
Phosphoric acid is a ternary medium-strength inorganic acid, displaying lower acidity than strong mineral acids (e.g., sulfuric, hydrochloric, and nitric acids) yet stronger acidic characteristics than weak acids such as acetic, boric, and carbonic acids. Its reaction with sodium carbonate produces different phosphate salts (e.g., sodium dihydrogen phosphate, disodium hydrogen phosphate) depending on the pH environment. The acid can cause skin irritation and tissue damage upon contact, and its concentrated form exhibits corrosiveness when heated in porcelain vessels. Due to its hygroscopicity, it requires storage in airtight containers.
Phosphoric acid (H₃PO₄, CAS 7664-38-2) is commonly supplied as a viscous, colorless, and odorless liquid with a sour taste, typically at a concentration of approximately 85%—equivalent to an 82% H₃PO₄ content. The notable viscosity of the commercial solution arises from extensive intermolecular hydrogen bonding. In its pure form, it may also occur as a crystalline solid. This hydrogen-bonded network contributes to the syrup-like consistency of the concentrated acid, which is widely used in various industrial applications.
Advanced Physicochemical Properties
