What is Benzoyl Peroxide?
Benzoyl Peroxide is an organic compound with structural formula C₅H₅−C(=O)O−)₂, abbreviated as BzO₂. It is a peroxide with a keratolytic, comedolytic, antibacterial, irritant, and anti-inflammatory action. It decomposes to release oxygen which is lethal to the bacteria Propionibacterium acnes. Benzoyl Peroxide appears as odourless white granules or powder. It is sparingly soluble in water. It enhances the turnover rate of epithelial cells, through peeling the skin. The Benzoyl Peroxide is an oxidizer, which is generally utilised in the generation of polymers.
Structure of Benzoyl Peroxide
The chemical structure of a molecule in the Benzoyl Peroxide involves the arrangement of the atoms and the chemical bonds that holds all the atoms collectively. The Benzoyl Peroxide molecule comprises 29 bonds. There are 14 multiple bonds, 5 rotatable bonds, 19 non-H bonds, 2 double bonds, 12 aromatic bonds, and 2 six-membered rings. In the structure of Benzoyl Peroxide, the carbon atoms are intended to be placed at the edges, and the hydrogen atoms attached to carbon atoms are not indicated. Each carbon atom is estimated to be associated with sufficient hydrogen atoms to render the carbon atom with 4 bonds.
Properties of Benzoyl Peroxide
The Physical and Chemical Data of Benzoyl Peroxide are given below.
Chemical Properties of Benzoyl Peroxide
Benzoyl Peroxide is an explosive and hazardous chemical compound.
It causes swelling of the skin.
Benzoyl Peroxide is prepared by the treatment of Benzoyl Chloride with Barium Peroxide.
This compound readily supports homolytic fission to yield free radical products that are incredibly reactive.
As it contacts human skin, it breaks down to produce oxygen and benzoic acid.
Physical Properties of Benzoyl Peroxide
Benzoyl peroxide has a colourless crystalline structure.
It has a faint odour with a smell of benzaldehyde.
It is insoluble in water and slightly soluble in alcohols.
It is considerably soluble in chloroform and ethers.
The dry form of Benzoyl Peroxide is highly reactive and can explode.
Benzoyl Peroxide melts within 103 °C and 106 °C with dissolution.
1 g Benzoyl Peroxide fluxes in 40 ml of Carbon Disulfide.
Uses of Benzoyl Peroxide
Benzoyl Peroxide was first prepared by Liebig in 1858. Treatment with Benzoyl Peroxide was introduced for wounds by Peck and Chagrin in 1934, and for acne varioliformis and sycosis Vulgaris by Reynolds and Lyon in 1929.
Benzoyl Peroxide is an effective organic peroxide because of its wide variety of uses. It is also manufactured on a large scale industrially. Some of the uses of this organic compound are listed below.
This organic compound can be applied to human skin to treat acne if the concentrations are between 2.5% to 10%.
Benzoyl Peroxide is used to extract ink and dye stains from many gadgets such as vinyl dolls.
Benzoyl Peroxide is used as a bleaching agent in bread and cheese.
It is used in cosmetic hair colouring and tooth whitening processes.
It is also a very useful oxidant.
With the help of the Benzoyl Peroxide, the polymerization process of resins can be started.
In the synthesis of thermosetting polyester resins, it can also be used as a catalyst.
Benzoyl Peroxide Side Effects
Some of the side effects of benzoyl peroxide are given below.
Dry skin
Skin Irritation
Red skin or flaying skin
Skin Blisters
Swollen skin, tongue, face, or throat
Severe Dizziness
Breathing Problems
FAQs on Benzoyl Peroxide
1. What is Benzoyl Peroxide and what is its chemical formula?
Benzoyl Peroxide is an organic compound that is widely used for its antiseptic and bleaching properties. Chemically, it is a peroxide, meaning it has an oxygen-oxygen single bond. Its chemical formula is (C₆H₅CO)₂O₂. It is particularly known for being a source of free radicals, which makes it useful in many chemical reactions.
2. How does Benzoyl Peroxide work to treat acne?
Benzoyl Peroxide primarily treats acne by targeting the bacteria responsible for breakouts, known as Propionibacterium acnes. It works in two main ways:
- It releases oxygen on the skin, which creates an environment where these anaerobic bacteria cannot survive.
- It also has a keratolytic effect, meaning it helps to peel the top layer of the skin, clearing away dead skin cells and excess oil that can clog pores.
3. What are the different forms and concentrations of Benzoyl Peroxide available for skin treatment?
Benzoyl Peroxide is available over-the-counter and by prescription in several forms, including gels, creams, lotions, face washes, and soaps. It typically comes in different strengths, most commonly ranging from 2.5% to 10%. Lower concentrations, like 2.5% or 5%, are often as effective as higher ones but with fewer side effects like dryness and irritation.
4. Besides acne treatment, what are some other important uses of Benzoyl Peroxide?
While famous for skin care, Benzoyl Peroxide has significant industrial uses. It is a key chemical in:
- Polymerisation: It acts as an initiator for free-radical polymerization to produce plastics and resins.
- Bleaching: It is used as a bleaching agent for flour and in some teeth whitening products.
- Curing Agent: It helps in hardening certain resins and rubber compounds.
5. How is Benzoyl Peroxide different from Salicylic Acid for treating acne?
Both are effective acne treatments but work differently. The main difference is that Benzoyl Peroxide is antibacterial, killing the bacteria that cause acne. In contrast, Salicylic Acid is primarily an exfoliant (a keratolytic) that dissolves the oil and dead skin cells clogging the pores. Benzoyl Peroxide is better for inflammatory acne (red pimples), while Salicylic Acid is often preferred for blackheads and whiteheads.
6. Why is Benzoyl Peroxide considered a powerful oxidizing agent in chemistry?
Benzoyl Peroxide is a powerful oxidizing agent because of the weak oxygen-oxygen single bond (peroxide bridge) in its structure. This bond can easily break when exposed to heat or light, forming two benzoyloxy free radicals. These radicals are highly reactive and readily accept electrons from other substances, thereby oxidizing them. This property is what makes it an effective initiator in polymerization and a potent bleaching agent.
7. Is it safe to use Benzoyl Peroxide every day, and what precautions should be taken?
For most people, it is safe to use Benzoyl Peroxide daily, especially in lower concentrations. However, it is important to start slowly, perhaps every other day, to see how your skin reacts. Key precautions include:
- Always apply a non-comedogenic moisturiser to combat dryness.
- Use sunscreen daily, as it can make your skin more sensitive to the sun.
- Avoid contact with hair and coloured fabrics, as it can bleach them.
8. Can Benzoyl Peroxide help remove old dark spots or acne scars?
No, Benzoyl Peroxide is not effective for treating old dark spots (post-inflammatory hyperpigmentation) or pitted acne scars. Its main function is to treat active acne by killing bacteria and unplugging pores. While it can prevent new breakouts that might cause future spots, other ingredients like Vitamin C, retinoids, or azelaic acid are better suited for fading existing hyperpigmentation.
