THE CHEMISTRY OF PERFUMES: MOLECULES THAT EVOKE MEMORIES

Perfume is something which connects nature, science and our emotions. Fragrances always played a role in a our life, from censers also known as perfume burners to flacon which we now have in our shelves. But has anyone ever wondered, what is the science behind a fragrance? How do people generate artificial scents which never existed naturally? How does it smell that way it does? Why do some scents last longer than the others? The answers to these questions are situated within the heart of chemistry of perfumes.It is a subject of learning where each molecule has some story and every scent stirs up a memory.

SINCE WHEN DID THE IDEA OF PERFUME COME INTO PICTURE?

It dates back to thousands of year ago when ancient Egyptians burned frankincense in order to elevate their spiritual atmosphere, when Greeks and Romans started mixing various oils with flowers, great Islamic scholars like Avicenna finding ways to extract essential oils from herbs and roses using the method of distillation.

It was back in 1868 when the discovery of the molecular structure of the chemicals in scents became revolutionary. Creating Vanillin which is the main scent of vanilla and another sweet, new hay-like smell called Coumarin substantiated that labs could really create scents parallel to the level nature does. 

Soon perfumes could be generated artificially and no longer required the harvesting of beautiful, delicate flowers or extracting scents from rare animal products.

REASON BEHIND LONGEVITY OF A PERFUME

The answer is volatility - meaning the rate at which molecules evaporate. The sole reason why earthy and musky fragrances last longer than scents which are citrusy. Also, alcohol which is the most commonly used solvent makes the perfume more stable. They have a unique methodology to create perfume in a pyramid fashion. It has three notes: - 

Base notes including woods,musks,resins.

Heart notes with floral scents and spices

Top notes being light and fresh like lemon aldehyde.

Further, fixative is to be added without which perfumes would not last longer than few seconds. Fixative is a substance with low volatility which were previously made from Ambergris and now they've switched to the synthetic options of Ambroxide and Muscone. Beta- ionones and Iso E Super are also the well know fixatives which possess smell too.

THE SIGNIFICANCE OF BETA-IONONE IN PERFUMES

Beta-ionone has a sacred spot amongst hundreds of fragrance molecules. Have you ever smelled a violet (Viola odorata)? It is beta-ionone that give this floral scent soft and powdery feel. It is created by breaking down beta carotene. It has a molecular structure of a cyclic ketone with conjugated double bonds which interfaces with the olfactory receptors in a definite manner, hence developing a distinct violet-like scent. The smell of beta-ionone is so potent ,that even a trace amount when added to a perfume alters its entire essence. Manufacturing sector are no more dependent on chemical synthesis. Yeasts and microbes are genetically manipulated to synthesize beta-ionone efficiently and hence the need for plant harvesting has reduced considerably.

β-Ionone

MODERN SYNTHETIC PERFUME MOLECULES 

Have you ever had the experience of smelling a fragrance which feels airy,woody and futuristic all at once? It is the molecule called Iso E Super which is added in cosmetics and sunscreens because of its ability to absorb UV radiation. Its smell is being brushed aside but it has this woody, velvety smell which often smells like skin. It has also got this unique ability to mix easily with other scents making them more potent. It is a mainstay of majority of the modern perfumes being the single most star of Escentric Molecules 01 before.

Iso E Super showcases the artistry of synthetic chemistry. It is not only able to design scents which were never developed by nature but also able to resonate with human emotions.

Iso E Super

ONGOING EVOLUTION OF PERFUME CHEMISTRY 

The craftsmanship of perfumes has always been a demonstration of technology.

Before it focused on methods like distillation which resulted in organic synthesis, but in this era of green chemistry and biotechnology, it is focusing on eco-friendly methods to protect our planet. To reduce and eliminate the harmful extraction methods, microbial fermentation is helping us generate compounds like beta-ionone and musks.

For the smells which require complex methods and are tricky, flow chemistry helps in reducing the waste with simultaneously increasing the production.

Catalytic and photochemical reactions have been like a mysterious formula to stir up the aroma molecules substantially. And the recent encapsulation techniques are ensuring long lasting freshness by the method of controlled release of perfumes in air fresheners, detergents and textiles.

WHY DO PERFUMES INVOKE MEMORIES AND EMOTIONS?

Its the most alluring question and the answer to this lies in neuroscience, how our sense of smell connects our emotion and memory centers in brain. It is the way a molecule is assembled -its rings, bonds and some extra substituents. It influences the way a smell is perceived by our olfactory receptors. This interaction induces a signal to the brain which is perceived as smell and becomes a memory.

Hence, an Iso E Super gives you the experience of soaking in the sun or a trace scent of jasmine makes you revisit a summer night.

As said earlier, perfumes are an excellent blend of science and art. It’s not just a product of grandeur, but a chemistry that brings us back to memories and feelings. Biotechnology and Green chemistry are moulding the future of fragrances where they will not be limited to exquisite smells, but they will also be environmentally cautious and ethical.

Wonder which molecules are dancing up in the air and what story they have to tell you the next time you spray yourself your special perfume!

By,

Heeral Jain (B221052)

Dhruv Gandhi (B221059)