The key difference between benzophenone-3 and benzophenone-4 is that in sunscreen products, benzophenone-3 can be used at 6% concentration or below, whereas benzophenone-4 is used at 10% concentration or below.
Sunscreen or sunblock (sometimes known as sun cream as well) is a protective topical product we use on the skin. They are absorbed by the skin and reflect some of the sun’s UV radiation to protect the skin from sunburns and prevent skin cancer. Benzophenone-3 and benzophenone-4 are two important ingredients used in sunscreen products in different concentrations.
CONTENTS
1. Overview and Key Difference
2. What is Benzophenone-3
3. What is Benzophenone-4
4. Benzophenone-3 vs Benzophenone-4 in Tabular Form
5. Summary – Benzophenone-3 vs Benzophenone-4
What is Benzophenone-3 (Oxybenzone)?
Benzophenone-3 or oxybenzone is an organic compound having the chemical formula C14H12O3. It exists as a yellow-colored solid that can readily dissolve in many organic solvents. Furthermore, this compound belongs to the class of aromatic ketones named benzophenones. We can find benzophenone-3 naturally occurring in flowering plants. It is also useful in many sunscreen lotions. Moreover, this substance is useful in many plastics, toys, furniture finishes, and various other products.
Benzophenone-3 is a conjugated molecule that can absorb light at lower energy levels in comparison to many other aromatic compounds. It has a hydroxyl group that is hydrogen-bonded to the ketone. This hydrogen bonding interaction can contribute to the light-absorption properties of this compound. This specific property makes it a proper ingredient in sunscreen products.
The major method of producing benzophenone-3 is the Friedel-Crafts reaction of benzoyl chloride with 3-methoxyphenol. The molar mass of benzophenone-3 is 228.24 g/mol. Its melting point is 62 °C, while the boiling point can range from 224-227 °C. The density of benzophenone-3 is about 1.20 g/cm3. The flash point of this compound is 140.5 °C. This means 140.5 degrees Celsius is the lowest temperature at which the liquid state of this compound gives off vapor in a quantity that is capable of forming an ignitable vapor/air mixture.
Figure 01: The Chemical Structure of Benzophenone-3
There are many uses of benzophenone-3, which include the use of this substance in plastics as a UV light absorber and stabilizer. Moreover, we can use it along with other benzophenones to be used in sunscreen lotions, hair sprays, and cosmetic applications. This is mainly because these substances can prevent potential damage from exposure to sunlight. In addition, we can find this ingredient in nail polish. Oxybenzone is also important as a photo stabilizer for synthetic resins.
What is Benzophenone-4?
Benzophenone-4 is an organic compound having the chemical formula C14H12O6S. It is also known as sulisobenzone, and it is a common ingredient in sunscreen products that can protect us from damage by UVB and UVA light rays. The molar mass of this compound is 308.31 g/mol. The melting point of this compound is 145 degrees Celsius while the boiling point is 491 degrees Celsius. We can classify it as a sulfonic acid compound, and it has poor solubility in water.
Figure 02: The Chemical Structure of Benzophenone-4
According to the Cosmetic Ingredient Review expert scientific panel, this compound and other derivatives of benzophenone are safe as typically used in cosmetics and personal care products. However, this substance in higher concentrations can be persistent, bioaccumulative, and toxic. Therefore, they can be linked to cancer, endocrine disruption, and organ system toxicity. Due to this reason, this ingredient is banned from using it in food packaging and the food industry in the USA.
What is the Difference Between Benzophenone-3 and Benzophenone-4?
Benzophenone-3 and benzophenone-4 are derivatives of benzophenone. The key difference between benzophenone-3 and benzophenone-4 is that in sunscreen ingredients, benzophenone-3 can be used in 6% concentration or below, whereas benzophenone-4 is used in 10% concentration or below.
The below infographic presents the differences between benzophenone-3 and benzophenone-4 in tabular form for side-by-side comparison.
Summary – Benzophenone-3 vs Benzophenone-4
Benzophenone-3 or oxybenzone is an organic compound having the chemical formula C14H12O3. Benzophenone-4 is an organic compound having the chemical formula C14H12O6S. The key difference between benzophenone-3 and benzophenone-4 is that in sunscreen ingredients, benzophenone-3 can be used in 6% concentration or below, whereas benzophenone-4 is used in 10% concentration or below.
Reference:
1. “Benzophenone & Related Compounds.” Safe Cosmetics.
Image Courtesy:
1. “Oxybenzone” By Fvasconcellos – Own work (Public Domain) via Commons Wikimedia
2. “Sulisobenzon Structural Formula V.1” By Jü – Own work (Public Domain) via Commons Wikimedia