Making sunscreen from scratch

TL;DR

This video demonstrates the preparation of dye benzyl acetone, an active ingredient in sunscreen, through a straightforward aldol reaction.

Transcript

in this video we're going to be making some dye benzyl acetone which is often used as an active ingredient in sunscreen it's really good at absorbing UV which is why it's used in sunscreen but other than that it doesn't have too many uses this preparation is commonly done in teaching labs because it's a pretty easy example of an aldol reaction anyw... Read More

Key Insights

• 🧑‍🏫 Dye benzyl acetone is prepared through an aldol reaction, a commonly taught reaction in chemistry labs.
• ❓ The reaction involves mixing benzaldehyde, acetone, and sodium hydroxide.
• ❓ Precipitation, filtration, and recrystallization steps are utilized for product isolation and purification.
• 😒 Dye benzyl acetone exhibits UV-absorbing properties, making it suitable for use in sunscreens.
• ❓ The recrystallization process greatly improves the purity of the product.
• 🏆 The SPF of dye benzyl acetone can be determined through a simple comparison test.
• 💁 The video demonstrates the experimental procedure and provides useful tips for optimizing the reaction.

Questions & Answers

Q: What is the purpose of dye benzyl acetone in sunscreen?

Dye benzyl acetone is added to sunscreens for its UV-absorbing properties, providing protection against harmful rays.

Q: What role does sodium hydroxide play in the preparation?

Sodium hydroxide acts as a catalyst, speeding up the aldol reaction between benzaldehyde and acetone.

Q: Why is recrystallization performed on the product?

Recrystallization helps purify the dye benzyl acetone by removing impurities, leading to a higher melting point and better product quality.

Q: How is the SPF (sun protection factor) of dye benzyl acetone determined?

The SPF is calculated by comparing the time it takes for dye benzyl acetone-treated beads to change color under UV light to untreated beads.

Summary & Key Takeaways

• Dye benzyl acetone is commonly used in sunscreens due to its ability to absorb UV light.

• The preparation involves mixing benzaldehyde and acetone in the presence of sodium hydroxide.

• The product is obtained through precipitation and filtration, followed by recrystallization for purity.