anonymous asked:

do ever look at a crystal and think "hmm.. crunchy"

oh my god literally constantly and it’s horrible because for my work i’m literally synthesizing crystals in carcinogenic solvents!!! but in my head i’m like ‘yeah i DO wanna chomp on that tho’


A famous experiment which changed organic chemistry: purple benzene. 

Crown ethers are an unusual series of molecules that have the ability to complex small cations, notably alkali metals such as lithium, sodium and potassium. These cyclic molecules, upon complexing a cation, can allow a salt to go into organic solvent that otherwise wouldn’t. This makes reactions that are otherwise impossible accessible.

Charles John Pedersen (October 3, 1904 – October 26, 1989) was a pioneer of this field of chemistry. He was an American organic chemist best known for describing methods of synthesizing crown ethers.  He shared the Nobel Prize in Chemistry in 1987 with Donald J. Cram and Jean-Marie Lehn.

A good example is how 18-crown-6 (shown above) can help potassium permanganate (a beautiful purple oxidizing agent based on manganese (VII)) go into organic solvent. Normally, you can only get permanganate into very polar solvents (as seen on the first pics where the benzene dissolves 0% of the permanganate), but when adding 18-crown-6, it allows the permanganate ion to go into solution as well forming a beautiful purple solution as seen above.

An inspiring article, what is worth to read about crown ethers, by Charles J. Pedersen

chemical fumes

Yesterday I noticed the smell of ethyl acetate leaking from the undergrads’ bench and advised them to use it in the hood. This started a big conversation about chemical odors.

I discovered that my olfaction is (somewhat) keener than average people since I was young, and while it’s been going slowly downhill since I started working with smelly chemicals more than 4 years ago, I’d say it’s still pretty decent. My colleague Tom always jokes about how bad his sense of smell is especially after he started working in the lab.

So returning to ethyl acetate, a commonly-used solvent in organic chemistry. My first contact with this chemical is probably from a bubble-blowing paste I used to play when I was like 5 years old. And in middle school science lab I synthesized it by Fischer esterification where students were directed to detect the presence of it by the characteristic smell. To me, ethyl acetate has a fruity smell (some friends of mine said it reminded them of durian) which can be detected in small concentrations in the air. It is not particularly unpleasant, but it gets strong and unbearable pretty easily. It can get to a point where I can even sense a vinegary odor from the amount of acetic acid from the hydrolysis of it on contact with atmospheric moisture! For this reason I always have words about people using ethyl acetate outside the fume hoods.

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The Artist and Muralist: Onur Dinc

Based in Solothurn, Switzerland though with Turkish roots, the Onur is part of the photorealist scene. He mostly paints using acrylic rollers and with the help of brushes. An experimental use of UV-light sensitive paints or solvents has produced astonishing effects in his large-scale works. 

Onur grew up in Zuchwil in Switzerland’s Solothurn canton. After leaving school, he completed training as a painter, followed by an apprenticeship as a theater painter in Solothurn. Onur then trained as a graphic artist at the advertising agency in Basel, going on to work in the profession for a year in Bern. In 2007 and 2008, he returned to the theater, this time in Lucerne. Since 2008 he has worked as an independent painter and muralist. Follow him on Instagram and Facebook.

View similar posts  | selected by Margaret


A special organic dye, Nile Red in different solvents.

From left to right I dissolved equal amounts of Nile Red (a dye) in different solvents. The solvents were: methanol, diisopropyl ether, hexane, n-propanol, tetrahydrofuran, toluene, ethanol, acetone.

Depending on the solvents polarity, the dye dissolved to give different colored solutions (upper image), this is called solvatochromism. It is the ability of a chemical substance to change color due to a change in solvent polarity.

Under UV light, these solutions emitted different colors (bottom pics), this is called solvatofluorescence. The emission and excitation wavelength both shift depending on solvent polarity, so it fluoresces with different color depending on the solvent what it’s dissolved in.

Nile Red is a quite expensive dye, which costs a bit over 1000 USD/gram, therefore I had to make it. The purification of the raw material was posted HERE

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