Ammonium Persulfate

Ammonium Persulfate (APS), also known as diammonium peroxodisulfate, is an ammonium salt with the chemical formula (NH₄)₂S₂O₈ and a molecular weight of 228.201 g/mol.

Research shows that ammonium persulfate, an oxidizing and bleaching agent, is widely used in the battery industry, as a polymerization initiator, and as a desizing agent in the textile industry. It is also used for surface treatment of metals and semiconductor materials, etching in printed circuit boards, hydraulic fracturing in oil extraction,  flour and starch processing, oil and fat industry, and removing hypo in photography.

1. Physical and Chemical Properties
• Main Component: Industrial-grade, content ≥ 95%.
• Appearance: Colorless monoclinic crystals, sometimes slightly green, with hygroscopic properties.
• Chemical Nature: Ammonium persulfate is the ammonium salt of peroxodisulfuric acid. The peroxodisulfate ion contains a peroxide group and is a strong oxidizing agent.
• Thermal Decomposition: At 120°C, it decomposes, releasing oxygen and forming pyrosulfates.
• Oxidizing Ability: It can oxidize Mn²⁺ to MnO₄⁻.
• Preparation: Produced by electrolyzing ammonium hydrogen sulfate aqueous solution.

Key Parameters:
• Melting Point: 120°C (decomposes)
• Boiling Point: Decomposes before boiling
• Density (Water = 1): 1.982
• Vapor Density (Air = 1): 7.9
• Solubility: Easily soluble in water

Chemical Reactions:
• (NH₄)₂S₂O₈ + 2H₂O ⇌ 2NH₄HSO₄ + H₂O₂
• Ionic Equation: (NH₄)₂S₂O₈ ⇌ 2NH₄⁺ + S₂O₈²⁻
• S₂O₈²⁻ + 2H₂O ⇌ 2HSO₄⁻ + H₂O₂
• HSO₄⁻ ⇌ H⁺ + SO₄²⁻

The solution is acidic due to hydrolysis, and adding nitric acid can inhibit the forward reaction.

2. Main Applications
• Analytical Chemistry: Used for detection and determination of manganese as an oxidizing agent.
• Bleaching Agent: Commonly used in the textile industry and soap industry.
• Photography: Used as a reducer and retarder.
• Battery Industry: Acts as a depolarizer.
• Polymerization Initiator: Used in the emulsion polymerization of vinyl acetate, acrylates, and other monomers. It’s cost-effective and produces water-resistant emulsions.
• Curing Agent: Used in the curing of urea-formaldehyde resins, offering the fastest curing rate.
• Adhesive Additive: Enhances the adhesive quality of starch adhesives by reacting with proteins. Recommended dosage: 0.2%–0.4% of starch content.
• Surface Treatment: Acts as a metal surface treatment agent, especially for copper surfaces.
• Chemical Industry: Used in the manufacturing of persulfates and hydrogen peroxide.
• Petroleum Industry: Used in oil extraction and hydraulic fracturing.
• Food Industry: Functions as a wheat improver and a mold inhibitor for beer yeast.

3. Hazards
• Hazard Classification: Class 5.1 Oxidizing Solids
• Health Hazards:
• Causes irritation and corrosion to skin and mucous membranes.
• Inhalation can cause rhinitis, laryngitis, shortness of breath, and coughing.
• Contact with eyes and skin can result in severe irritation, pain, and burns.
• Ingestion may lead to abdominal pain, nausea, and vomiting.
• Prolonged skin exposure may cause allergic dermatitis.
• Fire and Explosion Hazard: Supports combustion and can cause burns and irritation upon contact.
• Stability: Relatively stable in low-concentration aqueous solutions but requires careful handling and storage.

Storage and Handling Precautions:
• Store in a cool, dry place, away from direct sunlight and moisture.
• Avoid contact with flammable materials and reducing agents.
• Wear appropriate personal protective equipment (PPE) during handling.
• Regularly inspect stored chemicals to ensure stability and prevent accidents.

Ammonium persulfate is a critical chemical reagent across various industries, and proper handling and sourcing from reputable suppliers are essential to ensure safety and optimal performance.