Archive for November 13th, 2009
Sandalwood
by kgardner on Nov.13, 2009, under ChemSem 10
Dr. Jeffrey Turk came to talk to us today from Alma College about “Sandalwood: More than just a pleasant smell”. He started out talking about the sense of smell and how we smell, with molecules coming in through the nose and landing on the olfaction receptor cells which contain 7 TM protein coupled receptors. The structure of these receptors changes, leading to changes with the cell, and the signal goes from these receptor cells to the olfactory bulb to the olfaction cortex. The amazing thing about all of this is that there is not a receptor for each type of cell, but these receptors can bind multiple odorants, and each odorant can bind to many different receptors, giving a wide variety of options for these receptors to sense smell.
He then moved into the chemistry of all of this, showing us how different isomers can give different smells. It is really interesting how the research is done for odors and creating new smells. There is natural oil that comes from nature, or these chemists can take the structure of that oil and create the same structure in the lab, leading to a nature identical smell. Or they can take what they know of different molecular groups and how they are known to smell, and they can create new smell combinations, or synthetic.
Dr. Turk brought in many samples of smell with him, letting us smell the differences that the addition of molecules like javanol will do to the final smell of a perfume. One of the really interesting things we got to smell was ambergris, which comes from hardened whale poop that washes up on the shore and hardens in the sun. He was a very good speaker, keeping our attention with these samples to smell and having many illustrations on PowerPoint for us to follow.
If I was going to explain this to a non-chemistry student I would say that Dr. Turk talked about the chemistry involved with the things we smell, and the research that goes into creating new smells.
Sandalwood: More than just a pleasant smell
by Troy on Nov.13, 2009, under ChemSem 10
Unbelievably, this is the last non-student seminar presentation of the semester. There have been many great speakers thus far, some who have stirred us to think deeper about chemistry and some who have stirred up other feelings. This week we had a lot of fun hearing about and smelling chemistry. Dr. Jeffrey A. Turk is a chemist working as a faculty at Alma College in Alma, MI. His specialty is making odorous chemicals to be used in perfumes and colognes.
Dr. Turk introduced us primarily to the sandalwood odor, a natural fragrance acquired from the oils of a certain species of sandalwood tree. It would obviously be ludicrous to utilize nothing but the natural oils for making perfumes, as there would be a huge deficiency (extinction) of sandalwood trees in India. This is where chemistry comes in. Dr. Turk showed a big list of all the various types of volatile alcohols present in sandalwood oils that contribute to the characteristic odor of the sandalwood tree. One of his primary concerns is to maintain a high level of atom efficiency, much like Dr. Yamamoto. He claims that the most economic method to achieve synthesis of multiple complex molecules is by the familiar method of Claisen Rearrangement. This way, there are no atoms lost in the transformation of one chemical species into another.
Although Dr. Turk is familiar with the best way to go about concocting a fragrance that will be appealing, there is still a mighty amount of guesswork involved. Although all the sandalwood derivatives smell very similar to each other, mixing and creating new species will always have uncertainty. Dr. Turk did an outstanding job of engaging the students and of making the material interesting and fun. I enjoyed the presentation as did all others. Dr. Turk gets a 9.5/10 for chemistry content, 9.5/10 for professionalism and 10/10 for student engagement. Very good!
To the layperson, this seminar was all about the chemistry behind common perfumes.
Using an Extra Sense in Chem Sem
by ckrym on Nov.13, 2009, under ChemSem 10
Chemistry Seminar on November 12, 2009 incorporated a sense we do not usually use in seminar, our sense of smell. I would love to say we used our sense of taste. However, in the chemistry world eating lab materials is generally frowned upon. The presentation entitled “Sandalwood: More than just a pleasant smell” was given by Jeffrey A. Turk. Dr. Turk, a professor at Alma College who focuses on fragrance research.
Dr. Turk began by explaining how we smell. There are cilia cells in the nose that are coated in olfactory receptor cells. These receptor cells will respond to multiple odorants and send a signal to the olfactory bulb in the brain. The receptors do not recognize the properties of a molecule but the functionality. The olfactory bulb is linked to the hypothalamus which leads to smells linked to memory. Molecules involved in scent have an “ot”, an odor threshold. The smaller the odor threshold number is the stronger the smell. Different enantiomers will have different thresholds and even different smells. For example, Dr. Turk let us smell both the (S)-configuration of carvone, which smelled like caraway, and the (R)-configuration of carvone, which smelled like spearmint.
Dr. Turk specifically is working to use atom efficient reactions, like the Claisen rearrangement, to make synthetic fragrances with little waste. He works with synthesized molecules that produce the smell of sandalwood like Firsantol.
A side note of the presentation included smelling Ambrox which is a component of ambergris, or dried up whale poop. I’m not being sarcastic when I say that it smelled really good. This presentation was very interesting. I loved the fact that we actually got to smell the molecules we saw. Dr. Turk did an excellent job of introducing us to the topic of fragrance chemistry.
In telling my family or friends about this seminar I would say we learned about how organic molecules influence fragrance.
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