The violet perfume chemistry demonstration is one of the easiest demonstrations you can perform and also one of the most memorable. After all, most chemistry demonstrations smell awful! The reaction also goes by the names “odor of violets” or “flower shop reaction.”
All you do is mix two common, non-toxic chemicals and apply heat. The reaction releases ionone, which gives violets and roses their characteristic scents. Similar reactions produce the synthetic scents used in perfume making.
Violet Perfume Chemistry Demonstration Materials
You need washing soda (sodium carbonate) and castor oil. Sodium carbonate is used in laundry, cooking, and as a water softener. If you can’t find washing soda at the store, it’s easy to make it from baking soda. Castor oil is sold in pharmacies.
- Sodium carbonate or washing soda
- Castor oil
- Heat source
Perform the Demonstration
This demonstration is inexpensive, quick, and easy. You don’t even need to measure materials.
- Add a few drops of castor oil to a scoop of sodium carbonate in a heat-safe container, such as a glass test tube or small frying pan.
- Heat the base of the container using a flame or burner until white vapor rises from the chemicals.
- Remove the container from heat and walk around the room with it so the fragrance spreads. Do you smell the odor of violets?
How It Works
Perfumers and scientists apply organic chemistry when they make synthetic fragrances used in perfume, toiletries, and recipes. The reaction between sodium carbonate and castor oil involves a lot of steps, but the end result is a molecule called indole. Citral, acetone, and calcium oxide participate in an aldol condensation, followed by a rearrangement reaction, forming both alpha-ionone and beta-ionone.
The mixture of alpha and beta-ionone smells like violets. Beta-ionone on its own smells like roses. Flowers make ionone by degrading carotenoids, which are pigment molecules.
The Scent That Keeps Smelling Good
Ionone, violets, and roses have an interesting property. They temporarily steal your sense of smell. Ionone binds to scent receptors in the nose, stimulating them and sending a signal to the brain so you smell flowers. The molecule sticks to the receptors for a few moments, temporarily blocking any new stimulus. Another ionone molecule comes along and binds to the receptor. Your brain registers this is a new scent. So, whether you like the aroma or not, it’s a scent that neither becomes overpowering nor fades.
- Baldermann, S.; Kato, M.; et al. (2010). “Functional characterization of a carotenoid cleavage dioxygenase 1 and its relation to the carotenoid accumulation and volatile emission during the floral development of Osmanthus fragrans Lour”. Journal of Experimental Botany. 61 (11): 2967–2977. doi:10.1093/jxb/erq123
- Curtis, T; Williams, D.G. (2001). Introduction to Perfumery (2nd ed.). Fort Washington, New York: Micelle Press. ISBN 9781870228244.
- Lawless, Julia (2013). The Encyclopedia of Essential Oils: The Complete Guide to the Use of Aromatic Oils in Aromatherapy, Herbalism, Health, and Well Being. Red Wheel. ISBN: 978-1573246149.
- Russell, A.; Kenyon, R.L. (1943). “Pseudoionone”. Organic Syntheses. 23: 78. doi:10.15227/orgsyn.023.0078