Introduction to Benzoyl Peroxide: More Than Just an Acne Treatment
When you hear the term "Benzoyl Peroxide, CAS No 94-36-0," the first thing that likely comes to mind is a common acne-fighting ingredient found in countless skincare products. While this is one of its most visible applications, the story of this versatile organic compound is far more complex and industrially significant. Benzoyl Peroxide (BPO) is a workhorse chemical that plays a critical role in the manufacturing of plastics, the bleaching of food products, and the curing of composite materials, making it an indispensable component in numerous global industries.This comprehensive guide is designed to be your ultimate resource for all information related to Benzoyl Peroxide CAS 94-36-0. We will delve deep into its fundamental chemical structure and properties, explore its multifaceted applications beyond the medicine cabinet, and provide crucial safety data for proper handling. Whether you are a chemist, a manufacturer, a student, or simply a curious individual, this article aims to provide a thorough understanding of why this specific chemical, identified uniquely by its CAS Registry Number 94-36-0, is so important.
Why is CAS No 94-36-0 Important?
The CAS Registry Number, assigned by the Chemical Abstracts Service, is a unique numerical identifier for every chemical substance. CAS No 94-36-0 refers unequivocally to benzoyl peroxide. This designation is crucial for avoiding confusion arising from different nomenclature systems and for precise searching in scientific databases, safety sheets (SDS/MSDS), and regulatory documents. Throughout this article, we will consistently use Benzoyl Peroxide, CAS 94-36-0 to ensure clarity and accuracy.
Chapter 1: Chemical and Physical Properties of Benzoyl Peroxide (CAS 94-36-0)
To understand the applications of Benzoyl Peroxide, one must first understand its fundamental nature. This section details the key chemical and physical properties that define its reactivity and determine its uses.
1.1 Molecular Structure and Formula
The power of Benzoyl Peroxide lies in its molecular architecture.
- Chemical Formula: C₁₄H₁₀O₄
- Chemical Structure: Benzoyl Peroxide is an organic compound belonging to the peroxide family. Its structure consists of two benzoyl (C₆H₅C=O) groups connected by a peroxide linkage (-O-O-). This -O-O- bond is relatively weak and is the key to its function as a radical initiator.[Image Suggestion: A clear diagram of the Benzoyl Peroxide molecular structure, with labels for the benzoyl groups and the peroxide bond.]
1.2 Physical Properties and Identification
- Appearance: White, crystalline solid or powder. Commercial grades may contain water to enhance safety.
- Odor: A faint, characteristic odor of benzaldehyde (a faint almond-like scent).
- Molecular Weight: 242.23 g/mol
- Melting Point: Approximately 103-105°C (217-221°F) with decomposition. It is important to note that BPO melts with simultaneous decomposition, meaning it starts to break down as it melts.
- Solubility: Benzoyl Peroxide CAS 94-36-0 is soluble in many organic solvents such as chloroform, benzene, and dichloromethane. It is practically insoluble in water.
- Density: ~1.33 g/cm³
- CAS Number: The unique identifier, 94-36-0, is essential for unambiguous identification in commerce and regulation.
1.3 Chemical Properties and Reactivity
The most critical chemical property of Benzoyl Peroxide is its ability to undergo homolytic cleavage of the peroxide bond.
- Radical Initiation: When heated or exposed to light, the weak oxygen-oxygen bond breaks homolytically, generating two benzoyloxy radicals. These highly reactive radicals are the driving force behind its primary application: polymerization.
- Thermal Decomposition: The decomposition rate is temperature-dependent. This property is carefully controlled in industrial processes.
- Oxidizing Properties: As an organic peroxide, BPO is a strong oxidizing agent. It can ignite or explode when heated, contaminated, or mixed with combustible materials. This fundamental reactivity dictates the stringent safety measures required for its storage and handling.
Chapter 2: Primary Applications and Uses of Benzoyl Peroxide (CAS 94-36-0)
The utility of Benzoyl Peroxide spans from heavy industry to personal care. Its role as a free radical initiator is the common thread linking most of its applications.
2.1 Polymer Industry: The Largest Application
The predominant use of Benzoyl Peroxide CAS 94-36-0 is as a polymerization initiator, accounting for the majority of its global production.
- Polymerization of Vinyl Monomers: BPO is used to initiate the free-radical polymerization of key plastics and resins, including:
- Polyvinyl Chloride (PVC): For certain suspension polymerization processes.
- Polystyrene (PS): Used in the production of various plastic products.
- Polyethylene (PE): Particularly for Low-Density Polyethylene (LDPE).
- Acrylic Resins (PMMA): Used in sheets, coatings, and adhesives.
- Curing Agent for Thermoset Resins: It is extensively used to cure unsaturated polyester resins. This application is critical in the fabrication of:
- Fiberglass Reinforced Plastics (FRP): Used in marine components, automotive parts, and storage tanks.
- Solid Surface Materials: Like kitchen countertops (e.g., Corian).
- Gel Coats: Providing a high-quality finish on composite products.
2.2 Pharmaceutical and Dermatological Applications
This is the most well-known use of Benzoyl Peroxide among the general public.
- Acne Vulgaris Treatment: BPO is a first-line treatment for mild to moderate acne due to its threefold action:
- Antibacterial: It is highly effective against Cutibacterium acnes(formerly Propionibacterium acnes), the bacteria associated with acne.
- Keratolytic: It helps to break down and shed dead skin cells, preventing pore clogging.
- Anti-inflammatory: It has mild anti-inflammatory properties.
- Formulations: It is available in a wide range of over-the-counter (OTC) and prescription products, including washes, creams, gels, and lotions, typically in concentrations from 2.5% to 10%.
2.3 Food Industry: Bleaching and Maturing Agent
In the food industry, Benzoyl Peroxide CAS 94-36-0 is used as a bleaching agent, primarily for wheat flour and certain cheeses.
- Bleaching Flour: It bleaches the natural yellow pigments (xanthophylls) in flour, resulting in a whiter, finer-grained flour preferred for certain types of bread and cakes. It also acts as a maturing agent, improving the baking quality of the flour by oxidizing the gluten.
- Regulatory Status: Its use in food is strictly regulated. In the European Union, it is banned as a food additive (E928). In the United States and Canada, it is permitted with specific limits, and it must be declared on ingredient labels.
2.4 Other Specialized Uses
- Dental Care: Used in "thermo-paste" for root canal treatments and in some tooth-whitening systems.
- Adhesives and Coatings: As a curing agent for acrylic-based adhesives and coatings.
Chapter 3: Manufacturing and Synthesis of Benzoyl Peroxide
The industrial production of high-purity Benzoyl Peroxide CAS 94-36-0 is a carefully controlled chemical process. The most common method involves the reaction of benzoyl chloride with hydrogen peroxide in an alkaline medium.Reaction:Benzoyl Chloride + Hydrogen Peroxide + Sodium Hydroxide → Benzoyl Peroxide + Sodium Chloride + WaterThe process is typically carried out in water, and the resulting BPO is filtered, washed, and dried. For safety reasons, it is often sold as a wet paste or desensitized with water or phlegmatizers (like dicyclohexyl phthalate) to reduce its sensitivity to shock and friction.
Chapter 4: Safety, Handling, and Storage of CAS 94-36-0
Due to its strong oxidizing nature, handling Benzoyl Peroxide requires strict adherence to safety protocols. This information is critical and should always be cross-referenced with the specific Safety Data Sheet (SDS) provided by the supplier.
4.1 Hazards Identification
- GHS Hazard Statements:
- H241: Heating may cause a fire or explosion.
- H315: Causes skin irritation.
- H319: Causes serious eye irritation.
- H335: May cause respiratory irritation.
- GHS Pictograms: Flame over Circle (Oxidizer), Exclamation Mark (Irritant).
4.2 Safe Handling and Storage Practices
- Storage: Store in a cool, well-ventilated area, away from heat, sparks, and open flames. Keep away from combustible materials, reducing agents, and strong bases. Storage temperatures should be kept low, often below 30°C (86°F).
- Handling: Use non-sparking tools. Avoid friction, impact, and static discharge. Ground all equipment. Personnel should wear appropriate Personal Protective Equipment (PPE) including safety glasses, gloves, and flame-retardant lab coats.
- Incompatibilities: Benzoyl Peroxide CAS 94-36-0 is incompatible with amines, heavy metal compounds (e.g., cobalt, iron), and strong reducing agents, as these can catalyze its decomposition, potentially leading to a violent reaction or explosion.
Chapter 5: Regulatory Information and Environmental Impact
- REACH: Registered under the EU's REACH regulation.
- TSCA: Listed on the U.S. Toxic Substances Control Act (TSCA) Inventory.
- Environmental Fate: If released into the environment, BPO is expected to degrade. It is not considered highly persistent or bioaccumulative. However, as an oxidizer, it can be toxic to aquatic life.
Chapter 6: Global Suppliers and Market Overview
Benzoyl Peroxide CAS 94-36-0 is produced and supplied by numerous chemical companies globally. Key suppliers include:
- Arkema S.A.
- United Initiators
- Pergan GmbH
- Shandong Do Sender Chemicals Co.,Ltd.
- Akpa KimyaThe market is driven by demand from the plastics/polymer and pharmaceutical industries. Prices can fluctuate based on purity, grade (technical, pharmaceutical), and global supply chain dynamics.
Frequently Asked Questions (FAQs) About Benzoyl Peroxide CAS 94-36-0
Q1: What is the primary use of Benzoyl Peroxide CAS 94-36-0?
A1: While known for treating acne, its primary industrial use is as a free-radical initiator for the polymerization of plastics like PVC and polystyrene, and for curing polyester resins.
Q2: Is Benzoyl Peroxide safe for skin?
A2: In controlled concentrations (typically 2.5%-10%) in formulated dermatological products, it is generally safe and effective for acne treatment. It can cause skin dryness, irritation, and bleaching of hair and fabrics. A patch test is recommended.
Q3: Why is Benzoyl Peroxide considered hazardous?
A3: It is a strong oxidizing agent. When contaminated, confined, or exposed to heat or incompatible substances, it can undergo self-accelerating decomposition, leading to fire or explosion.
Q4: What is the difference between Benzoyl Peroxide and Salicylic Acid?
A4: Both treat acne but work differently. Benzoyl Peroxide CAS 94-36-0 is primarily an antibacterial and oxidizing agent. Salicylic Acid is a beta-hydroxy acid that exfoliates inside the pore. They are sometimes used in combination.
Q5: Where can I find a reliable Safety Data Sheet for Benzoyl Peroxide?
A5: SDS documents for CAS 94-36-0 are available from all major chemical suppliers (e.g., Sigma-Aldrich, Thermo Fisher Scientific) via their websites. Always consult the latest SDS before handling.
Conclusion
Benzoyl Peroxide, identified uniquely by CAS No 94-36-0, is a compound of immense industrial and pharmaceutical significance. Its simple peroxide bond belies a powerful reactivity that is harnessed to create the plastics that shape our modern world, the composites that make our vehicles stronger and lighter, and the medications that clear our skin. Understanding its properties, applications, and, most importantly, its hazards is essential for anyone working with or interested in this fundamental chemical. From the factory floor to the pharmacy shelf, Benzoyl Peroxide CAS 94-36-0 remains a testament to the power of molecular design in chemistry.
*Disclaimer: The information contained in this article is for informational purposes only. It is not a substitute for professional medical or chemical safety advice. Always consult the relevant Safety Data Sheet (SDS) and follow local regulations when handling any chemical substance.