Coby
moleculeoftheday
Posts by this author
September 15, 2008
The camping series continues. Previously: octenol, the related octenone, and DEET. Today we move away from insects for the time being, turning our attention to water purification.Sodium hypochlorite, or NaOCl, is sold as an aqueous solution - laundry bleach. It is also a great disinfectant, and…
September 12, 2008
I've been following this hurricane season unusually closely, because I know more people in affected regions than ever. My favorite place to stay caught up is Jeff Masters' blog. You can find lists of survivors and donate to hurricane relief at the Red Cross.
September 10, 2008
The ubiquitous active ingredient in insect repellent, DEET, is a great solvent. Anyone who's spent much time outdoors has discovered this empirically, as he's inevitably seen it fog polycarbonate glasses, dissolve a gear sack, or destroy $500 raingear.
DEET-based insect repellents come in a…
September 9, 2008
Yesterday, I discussed octenol, a lipid degradation product that's all over your skin. Ever wonder why a cut on your hand smells "like metal," or your hands smell "like metal" after handling some?
Metal ions are great at shuttling electrons around, and that's just what they're doing here. The iron…
September 8, 2008
The other day, I was trying to hunt down a tool for the lab. The closest store with any decent complement of tools is one of those big-box stores, so off I went. Unfortunately, I tend to get distracted in the presence of more than a few choices. Somehow, I found myself in the camping aisle, picking…
September 3, 2008
Oxymetazoline is yet another arylethylamine:
The broad class tickles adrenergic receptors in some way. This one finds use in nasal sprays and eyedrops, making you less dribbly and look less terrible in the morning, respectively.
August 27, 2008
Potassium chlorate, KClO3, is quite oxygen-dense and a potent oxidant. It is used in what we called "whippersnappers" and the suppliers called "Pop-Pops" as kids, along with silver fulminate. There is a singular irony in that the wimpiest firework, the one we could buy even in my solidly blue no-…
August 25, 2008
Sarin is an organophosphate that irreversibly inhibits cholinesterase. it's a neurotoxin, and a potent one. It'd be absolutely terrifying as a weapon, if it weren't so unstable. Even if a rogue state had gobs of Sarin last year, it's all pretty much a dud by now. The instability of acid halides (…
August 21, 2008
Short alkanoic acids stink. Apparently hexanoic acid smells of goats:
Hexanoic acid, as Dylan Stiles (L:tender P:button) memorably mentioned, smells of goats. Goats! Alkanoic acids smell of vinegar, cheese, vomit, poo, and, apparently, goats.
August 19, 2008
Sodium borohydride is intermediate to the jackhammer that is LAH and the pussycat that is cyanoborohydride.
Borohydride is just on the cusp of reducing protons to hydrogen. In acidic solution, it'll bubble off hydrogen, in basic solution, it's stable enough that Aldrich sells the stuff.
August 13, 2008
Trying to think of a molecule tonight, my friend suggested "pick an ugly one no one wants anymore...a clearance rack molecule." I immediately went to chlorinated solvents. They're in the backwater now, right? Carbon tetrachloride sure has a bad rep. I figured most of the organochlorides, except for…
August 11, 2008
Pyrene is a simple, four-fused benzene PAH:
What makes it neat is how it interacts with light. In particular, it's got some unusually sharp UV bands that are sensitive to solvent polarity. Additionally, the excited state dimer exhibits some especially unique photochemistry of its own, providing a…
August 7, 2008
I love reading lists of fragrance chemicals. The assignment of pleasant, qualitative fragrance descriptions to chemicals with hard-nosed, rigorous functional group names always makes me giggle a little. Acetophenone, for instance, smells of orange blossoms. Today, I came across one that has both in…
August 5, 2008
If you have been reading SB long enough to remember the DonorsChoose promotion, you might be interested in this. It's videos of scientists talking about their first experiments and why they like science, and if you vote on the one you like best, DC gets a buck. Check it out here.
August 4, 2008
Erythorbic acid is a common food additive:
It is a particularly good antioxidant, much like Vitamin C, and can be used to suppress the formation of carcinogenic nitrosamines in hot dogs and other cured meats.
July 29, 2008
As I mentioned yesterday, derivatives of arylethylamines - phenethylamine in particular - are drug targets in depression, but a sophisticated mechanistic understanding remains elusive. When you have some idea what molecule you'd like less of, a favorite trick is to find something (an "inhibitor")…
July 27, 2008
An aromatic ring, two carbons, and a nitrogen will get you a lot of places.From hallucinogens to decongestants to speed, the arylethylamine moiety works because it tickles neurotransmitter receptors. The effects of the assorted monoamine neurotransmitters are as varied as those of the drugs that…
July 24, 2008
Choline is an ubiquitous vitamin. Interestingly, it makes a number of "deep-melting eutectics" with other dirt-common chemicals like Urea.
When complexed in lecithin, it makes a nice edible detergent. Mayonnaise wouldn't be possible without it!
July 22, 2008
A lot of reactions with nucleophiles' rates are determined by how good a leaving group you have. For leaving group reasons and others, DMAP is a great organocatalyst:
I am a sucker for non-pharmaceutical chemicals with their own domains, so please enjoy dmapcatalyst.com.
July 18, 2008
As was mentioned in the comments to my entry on a refrigerant Monday, what we use has changed quite a bit over the years. If you don't know how a fridge or AC works (they're the exact same thing), here's what happens: know how evaporation something makes things cooler (e.g., sweat?). Condensing…
July 14, 2008
I really, really love refrigeration. I will go so far as to say that it's the most important invention of the modern era. More than internal combustion, nuclear bombs and power, or electrification, refrigeration defines the US. If you're like most Americans, you preside over at least THREE…
July 2, 2008
Dimethyl fumarate is a fungicide and sensitizer:
It appears it's made its way into some Chinese-manufactured leather sofas, and caused ill effects consistent with a sensitizer (basically an allergen) in some people.
Product-safety stories: they feel almost idyllic - they hearken back to last year…
June 30, 2008
In the news this week: aminopyralid:
Aminopyralid is an herbicide that may have made its way into some manure destined for home gardens and may have resulted in inferior produce. Interestingly, they think it's in manure not because of topical contamination, but via animals that ate contaminated…
June 25, 2008
Acetaldehyde is an intermediate metabolite of alcohol:
It's the first stop for ethanol on the way to benign acetate. Aldehydes tend to be short-lived and toxic species because of their reactivity, and acetaldehyde is no different. On the way to your hangover, though, alcohol goes from ethanol to…
June 24, 2008
Ornithine is an amino acid that occurs naturally in the body, but mostly as an intermediate in your body's nitrogen disposal cycle.
It rarely occurs in proteins, and we weren't sure why until some people tried to make some ornithine-containing polypeptides. Turns out it's not very well behaved,…
June 18, 2008
Chemistry spans orders of magnitude in terms of polarity. Many of the organic guys who read this work on stuff that never would dissolve in water (which becomes something of a pain when you try and make that something into a drug for aqueous things like people). And the biologists work on stuff…
June 16, 2008
That was probably the longest break ever. I'm trying to do better, but writing up multiple papers and grant applications, along with a pretty intense summer travel schedule just haven't augured well for the blogging. Onward and upward: tetrazole.
Tetrazole is one of those molecules I didn't…
June 1, 2008
Even in the case of floating severed feet, apparently!
Ebbesmeyer said it may not be a coincidence they were found in the same area. He said left shoes and right shoes often tend to wash up at different times at different places because they float differently.
He added that there are beaches that…
May 31, 2008
I've been thinking more about energy sources since oil was at $50/barrel . Since we reached the staggering heights of the last few months, I've been puzzling even more over what people will move to next.
Key to understanding this stuff is how much energy it takes to get your source in a useful form…
May 29, 2008
Gasoline and diesel engines operate using very different philosophies. In a gas engine, a spark ignites a compressed fuel-air mixture; in a diesel, air is compressed and gets very hot, and fuel is injected, resulting in ignition.
In the case of gasoline, the activation energy to start the fire is…