↓ Expand ↓

Archive → July, 2011

Top 10 most-read posts of July

David's Top 10 Reasons You Read This Blog in July. Credit: Pete Souza/Wikimedia Commons

Being a scientist and writer of a science blog, one can’t help being mesmerized by the statistics behind one’s readership. Over the last five years I’ve been quite surprised to see what posts garner a large number of readers and comments and which ones don’t (more often those that take a lot of time to write).

As posts gain traction among Google search returns on popular topics, you’ll often see old posts continuing to be among the most-read for months after writing.

So here are some data for you as well as a nice list of posts that you may have missed first time around:

Continue reading →

The smelly stuff

Having spent many years working in a manufacturing laboratory that stocked about 10,000 chemicals, I have a deep appreciation for the unique smells associated with organic compounds. A recent odor discussion on the ACS Division of Chemical Health & Safety e-mail list, in which a poster is attempting to locate and identify a particular “smelly socks” smell, has been fascinating.

It got me thinking, though, about how many different chemicals we’re potentially exposed to in a laboratory environment. Having spent more time recently in an industrial setting where respirators are commonly used, I wonder about the exposure hazards of chemical storerooms and open laboratories. Obviously, if you exceed the odor threshhold, you’re exposed to the particular chemical. And regardless of policies regarding the use of fumehoods for chemical handling, we’ve all experienced workplace odors and thus have all been exposed to low concentrations of a variety of assumably toxic compounds. Does the old saying, “That which does not kill us makes us stronger” apply here? Most of the chemists I know are both generally healthy and typically long-lived. Is there anything to the theory that extremely low concentration chemical exposures help our immune systems? Obviously there is no magic number below which exposures are guaranteed safe. How do you feel about this? Why don’t we see more respirator use in chemical laboratory settings?

Friday chemical safety round-up

Chemical health and safety news from the past week:

  • Not chemical, but since we posted about her death: Asteroid named in honor of Michele Dufault, the Yale senior who died after getting her hair caught in a machine shop lathe
  • Are former weapons sites in the U.K. still contaminated with hazardous materials? The Ministry of Defence says no, University of Leeds environmental toxicology professor Alastair Hay says more testing might be necessary
  • Cal/OSHA cites Baxter for worker death; Henry Astilla, 33, died after entering a nitrogen-filled tank and two other workers also had to be rescued. “Cal/OSHA levied a total of 11 citations carrying $371,250 in fines against Baxter, including four $70,000 fines for “deliberate and willful” failures to ensure worker safety.”
  • OSHA lists 147 employers as “Severe Violators” of worker–lots of construction, not much chemistry that I see, but I did notice…
  • Two Black Mag Industries gunpowder workers died in an explosion last fall in New Hampshire; OSHA issued 61 citations against the company and fined it $1,232,500. Although Black Mag initially appealed the citations, it wound up agreeing closing shop permanently: “Black Mag LLC, doing business as BMI and as Black Mag Industries, and Craig Sanborn, the company’s president, managing member and primary owner, have surrendered Black Mag LLC’s explosives manufacturing license and will permanently refrain from employing workers in any explosives-related business enterprise.”
  • U.K. companies Greenway Environmental and Pakawaste were fined US $368,903 for a 2007 fire in an aerosol can-shredding unit in which “Many of the aerosols shot into the air and onto nearby roads after setting alight, and neighbouring buildings were damaged”
  • Tesoro released its internal report (pdf) on the refinery explosion and fire last year in which five workers died and two more were badly injured. CSB is still investigating.
  • The Risk Science blog discussed Seven challenges to regulating “sophisticated materials”

Fires and explosions:

  • An unidentified chemical “self-heated” and started a fire at Specialty Tires of America in Pennsylvania. Anyone want to speculate what it was?
  • An “accident set a chemical cabinet filled with highly flammable material on fire” at L.M. Wind Power in Little Rock, Arkansas
  • And a fire broke out in a refrigerator used for chemical storage at Naeja Pharmaceuticals in Edmonton, Canada; CEO Chris Micetich said “staff heard what sounded like a champagne bottle popping in the fridge. ‘They opened up the fridge and they noticed there was a solvent that had spilled a little bit and while they were trying to determine what happened there was a spark and a flame broke out within the refrigerator.’” (Remember, if you’re storing flammable chemicals in a refrigerator, get one designed for such–don’t use an ordinary household fridge!)
  • Peroxide “improperly placed in the wrong location” caused an explosion at Lindau Chemicals in South Carolina
  • A tanker of sodium hydroxide exploded outside a hotel in Michigan; “the problem started with a compromised weld joint, and got worse from there. ‘The tank was not properly venting itself, and it built up pressure inside of the tank to the point where the leak did expand itself and started to hiss and with all the pressure it built up, it finally exploded,’ [fire chief Mike] Davidson said.
  • A hydrogen tank caught fire when an Air Liquide worker tried to deliver and hoook it up at Duferco Farrell in Ohio

Leaks, spills, and other exposures:

  • A valve failed on a liquid oxygen tank at Air Products & Chemicals in South Carolina. According to the news report, “The company says the oxygen is not harmful.” What about the combustion risk?
  • 2,000 pounds of molten aluminum spilled from a furnace at Hydro Aluminum in Florida, causing $30,000 in damage
  • 50 gallons of sulfuric acid leaked from an overhead pipe at Kidde Firefighting National Foam Division in Pennsylvania
  • 2 gallons of ethyl acetate spilled at Worldwide Clinical Trials in Texas
  • Containers of epoxy had some sort of reaction that led employees of Entec Composite Machines to call for hazmat help
  • Waste from the Xichuan Minjiang Electrolytic Manganese Plant contaminated the Fujiang River in China; “Tests of water samples from the river showed there is 1.888 milligrams of manganese per liter and 3.349 milligrams of ammonia and nitrogen per liter. The safe level is 0.1 and 0.5 milligrams, respectively.”
  • Some sort of chemical reaction caused a glass container to shatter at the University of Massachusetts, Dartmouth, School for Marine Sciences and Technology; one lab technician was cut. “The chemicals believed to be involved in the incident are vanadium penpoxide, sodium azide and acetic acid” (penpoxide = pentoxide, maybe?)
  • 3 pounds of mercury spilled at a home in Texas; too much for emergency hazmat crews to handle, so the Texas Commission on Environmental Quality is working with the homeowner’s insurance company to find a suitable contractor to clean up the mess

Not covered: meth labs; ammonia leaks; incidents involving floor sealants, cleaning solutions, or pool chemicals; and fires from oil, natural gas, or other fuels

Dow Selling Polypropylene To Braskem

There has been about as much news this week about Dow Chemical as there has been about the debt ceiling. (These two stories have even converged). I almost want to rename this blog The (Dow) Chemical Notebook.

In addition to building a ethanol-based polymers plant in Brazil, a massive $20 billion complex in Saudi Arabia, and a strong beat on earnings, Dow is also selling its polypropylene business to Braskem for $340 million–6.7x EBITDA for you deal nerds out there.

I do have a few observations:

1) This is the least surprising deal ever. Dow has been vocal about selling the business; Braskem has been public about wanting to make another North American acquisition to follow its purchase of Sunoco’s polypropylene business.

2) Dow’s polypropylene catalyst and licensing business isn’t included in the transaction. Since it bought Union Carbide in 2001, Dow has done some really nice work in advanced donors for polypropylene catalysts, which have given the Unipol PP platform a shot in the arm. I am very curious to see what Dow does with that business. And for that matter, I am curious to see what the future has in store for Dow’s HDPE business—which it has indicated it might divest—and its stake in the Unipol polyethylene licensing firm Univation.

3) Dow’s release implies a sequel. “The two companies will continue to evaluate potential future collaborations on growth opportunities in connection with their strategies,” it said.

4) Nowadays, propylene is hard to come by in North America. I wonder what Braskem is doing about sources of it.

BMS-AstraZeneca Dapagliflozin Diabetes Drug Falls Short; Pfizer’s Answer on the Horizon?

As reported by Nature News and Forbes’ The Medicine Show  on July 20, dapagliflozin, a BMS-developed diabetes drug marketed with partner AstraZeneca, was given a “thumbs-down” by an FDA review panel on July 19. After the 9-6 final vote, panel members commented favorably on the drug’s new mechanism, but evidently felt that the safety profile could not be overlooked: the FDA committee meeting statement mentions increased risk of breast and bladder cancer, increased genital infections, and perhaps most seriously, potential for drug-induced liver injury (DILI).

Dapagliflozin has been one of the rising stars of the new class of Sodium-Glucose cotransporter 2 (SGLT2) inhibitors for diabetes treatment, whose development roster includes Johnson & Johnson, Astellas, Boehringer Ingelheim, Roche, GSK, and Lexicon (Note:

see Nat. Rev. Drug Disc. 2010, 551 for a full recap).  The excitement behind these drugs comes from a relatively new idea for diabetes treatment: inhibition of the SGLT2 enzyme stops the kidney from reabsorbing sugar, leading to excretion of the excess glucose in the urine, which in turn lowers blood sugar. Dapagliflozin, like most SGLT2 inhibitors, is a glucose molecule with a large aromatic group attached to the carbon atom in the spot chemists call the anomeric position. Such so-called C-glycosides are thought to have improved staying power in the bloodstream relative to O-glycosides (where the linkage point is at an oxygen atom, a more common scenario in sugars), since they are less susceptible to enzymatic breakdown.

So, how do you improve these compounds? A paper Pfizer published last March (J. Med. Chem. 2011, 2952) may offer some hope.   Continue reading →

Getting to 54.5 MPG

If your very next car purchase had to meet the new mileage standards announced today, you’d be buying something roughly the size of a thimble. It would certainly be smaller than the petite Ford Fiesta, which gets a comparatively gluttonous 38 miles per gallon, highway.

Or, you could do away with any MPG concerns and get a new all-electric Nissan Leaf, though the range can dip down to around 62 miles.  Forget the comfy hybrid Toyota Prius – that one only gets 50 MPG overall.

Luckily for car buyers, automakers have until 2025 to get their fleet average up to 54.5 MPG. By then, the choices will be much different than today.

Today’s New York Times story on the increase focuses on plans for hybrid and electric cars. But other technologies will have to come into play. According to Sujit Das of the Center for Transportation Analysis at Oak Ridge National Laboratory, drive train changes will not be enough to meet the new standards.

There will be more electric and hybrid cars, but overall, Das says, passenger cars will also have to be made smaller and lighter. Part of the problem is that it is too expensive to make larger trucks and SUVs high mileage, and automakers still want to sell a lot of those. So, regular cars will have to be designed for REALLY high gas mileage to make the averages work out.

Oak Ridge scientists estimate that for every 10% of weight reduction in a vehicle, the gas mileage improves by 6.5%. To make that happen, they are studying how automakers can use lightweighting materials including advanced high-strength steels, aluminum, magnesium, titanium, and composites including metal-matrix materials and glass- and carbon-fiber reinforced thermosets and thermoplastics.

Automakers have been using lighter weight materials for years, but not in a quest to increase mileage. According to a report [PDF] by the Pew Center on Global Climate Change, “Although technology to improve vehicle efficiency is available and is being used in vehicles now, vehicle manufacturers have directed much of the potential of the technology to purposes other than fuel economy, such as making vehicles larger and more powerful.”  That’s a strategy that they’ll have to re-think.

Still, carbon fiber is not the first choice for automakers. Not too long ago I priced a carbon-fiber bicycle, and decided it was way too expensive. A carbon fiber car would be like George Jetson’s flying car that folds into a suitcase. It doesn’t exist, and if it did, very few people could afford it. Though parking would be a snap. The cost problem is a real barrier, which is why Oak Ridge scientists are also studying ways to make lightweighting materials more affordable.

Meanwhile, an organization called the Diesel Technology Forum says more people are choosing “clean diesel” cars, and that the new standards will bring more diesel models for consumers. The new diesel cars perform well on the highway – the Volkswagon Jetta TDI gets 42 MPG highway. A fiberglass and aluminum version would likely get even more.

The new mileage standards will also likely force automakers to experiment with more efficient designs for combustion engines.  New approaches get more mechanical power from the same amount of gas, bypassing steps where energy is lost as heat.

A start-up called Transonic Combustion builds a system that heats and pressurizes gasoline into a supercritical state before directly injecting it into the combustion chamber. There, like in diesel engines, no spark is needed to ignite the fuel and move the piston. It is an efficiency improvement that the company says can increase mileage by 50%.

DuPont gets Solar Blues from Innovalight

What is silicon ink? Is it magical pixie dust? Innovalight, maker of silicon ink, is a venture capital-funded company in Silicon Valley that was just acquired by DuPont. The announcement came Monday and I’ve been wanting to post about it but a small problem held me back.

Innovalight's silicon ink. Credit: Innovalight

I had no idea how Innovalight’s product works. I knew what it is though – it’s ink (and it sure looks like ink) made up of silicon nanoparticles suspended in chemicals. It can be screen printed in the same assembly line used to manufacture crystalline silicon solar cells.

The reason a manufacturer would add this extra step is simple. It increases the cell’s ability to capture energy from sunlight by 1%. 

Since Monday I’ve learned a bit more – enough to burden blog readers with my still incomplete understanding. Adding a precision-printed design of this ink to crystalline silicon solar cells allows the cell to capture more energy from the blue wavelength of sunlight. This sentence is where I would describe exactly how the ink makes that happen, so let’s pretend I did that.

Solar cells are generally hampered in their efficiency by an inability to capture energy from the full spectrum of light. Like the human eye, they do best capturing visible light. But that leaves a wealth of radiation in the UV and infrared part of the spectrum un-captured. Thus the 19% upper limit on even very efficient cells.

Interestingly, even within the visible spectrum, blue light is not well captured. My colleague Mitch Jacoby tells me that blue light is energetic enough for a solar cell to absorb and create a flow of energized electrons, but that the high energy electron and the “hole” left behind re-combine before they hit the conducting grids and without creating a current. Many people in many places like NREL have been studying ways to keep them separated and have them move to the negative and positive current collectors.

That’s why the DuPont press release about the acquisition talks about Selective Emitter solar cells. In spite of the capitalization, the term seems a bit misleading to me, because absorbing is what they’re going for. Anyway, selective emitter approaches involve an adaptation to the silicon, the surface and/or the conducting grid to make those electrons from the blue light migrate efficiently.

Innovalight’s value proposition is that solar cell manufacturers can make selective emitters in their current process by adding a silicon ink screen printing step after texturing the mono crystalline silicon.

According to the press release, “Selective Emitter technology could represent 13 percent of crystalline silicon solar cell production by 2013 and up to 38 percent by 2020.”

Working with fluorine

Digging back into ACS journals this week, I came across this warning in a 1976 Journal of Chemical Education paper (DOI: 10.1021/ed049p583) that discussed preparing perbromate by bubbling fluorine gas through an alkaline bromate solution:

There are problems associated with this preparative method for which precautions must be taken (8). For example, some fluorine escapes from the alkaline solution which results in small explosions above the reacting mixture, and the action of fluorine on Teflon sometimes results in fires.

Reference 8 took me to an Inorganic Chemistry paper from 1969 (DOI: 10.1021/ic50072a008):

Although most of the fluorine is absorbed by the base, enough escapes to make it imperative that the reaction be carried out in a well-ventilated fume hood. The reaction is not smooth, and small explosions may take place in the vapor above the solution. Under no circumstances should the apparatus be left to run unattended.

I wonder what exactly “small” means in the context of “small explosions.” Anyone want to share their experiences with handling fluorine?

For those who haven’t seen fluorine in action, here are the good folks of The Periodic Table of Videos visiting Eric Hope‘s lab at the University of Leicester, in the U.K.: