“The kind of whistling you would rather not hear in a chemistry lab”
Sep22

“The kind of whistling you would rather not hear in a chemistry lab”

From a reddit forum, a rather dramatic tale of what happens when nitric acid and ethanol are combined in a waste container: There were no empty nitric bottle in lab so rather than go get a new one 4 floors down, I grabbed a common use waste bottle. These are 4 liter glass bottles with a screw on cap.6 Usually they are used to collect organic waste, brought to a central facility where they are emptied and then thoroughly cleaned. University protocol is that they are first cleaned with ethanol, then water. The idea is that the only remnants in these bottles should be water. I happened to pick a bottle that had not been washed with water. Knowing that nitric acid was dangerous, I visually checked the bottle to make sure it was empty. There was a little bit of water (or so I thought)7 in the bottom, which did not concern me because nitric acid and water are fine to mix.8 I proceeded to clean my glass using a total of 30-50 mL of nitric acid, which I disposed of in the waste container. Knowing that nitric acid could react with organics, I left the waste bottle un-capped in my fumehood for about 60 seconds after I put the nitric in. Seeing no reaction, I then capped the waste bottle loosely. This probably saved me a trip to the hospital. Now, the astute chemist reading this may have figured out what happened next.9 Nitric acid and ethanol (remember this bottle was supposed to be washed with water, but never was) react very violently to produce heat and a large amount of gas. This reaction has an incubation time of a few minutes before it really kicks in. So 20 or so seconds after capping this bottle, I hear an ominous whistling sound. The kind of whistling you would rather not hear in a chemistry lab. I look at my fume hood and saw a very large and copious amount of brown gas (NOx) billowing out from my loosely fitted cap. As the whistling increased to a truly terrifying pitch, I had a few seconds to dive behind a wall before the waste bottle exploded with a force much larger than that mortar from the front page yesterday.10,11,12 Here I fucked up again as despite my 10 or so second lead time, I did not warn anyone that a glass shrapnel bomb was about to go off. I am so fucking lucky that no one decided to come around the corner at that moment. As the nitric acid tinged glass rained down upon me, my lab mates rushed...

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Lab coat versus concentrated acid
May19

Lab coat versus concentrated acid

Want a visual for why you should wear a lab coat? Check out Pictures from an Organic Chemistry Laboratory, where Kristof has a photo from a nitration that went awry, spilling concentrated sulfuric and nitric acid “everywhere.” It might even be an argument for adding an apron over a lab coat in some...

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Waste explosion at Texas Tech
Feb26

Waste explosion at Texas Tech

On Feb. 2, a glass waste bottle exploded in a Texas Tech University teaching laboratory, injuring three undergraduate students and a graduate teaching assistant. TTU has nowposted its investigation results online. In short, a nitric acid wash step was eliminated from the lab but the written instructions were not revised (I don’t know how this was communicated–with a verbal “skip step X”?). Nitric acid waste then wound up in a bottle with methanol and dimethylglyoxime, reactions ensued, pressure built up, and the bottle exploded when a student later tried to open it. The good: “All students and personnel were wearing appropriate personal protective equipment including lab coats, safety goggles and gloves.” The bad: The waste bottle was labeled with HNO3, HCl, methanol, and dimethylglyoxime. Clearly the lesson is not getting through to people that you can’t mix nitric acid with organics. Also, people need to keep written procedures up to date. It’s not hard to see how a verbal instruction would get ignored in favor of what’s written down, not to mention what happens if the person who historically runs the lab is out sick or has left the department. TTU is surely not the only institution challenged by these things. I would also argue that TTU should be commended for continuing to make its incident information available so that others in the academic and chemistry communities can learn from the experience. TTU’s action items to move forward: 1. EH&S will be providing pressure relief caps to waste storage bottles that contain inorganic acid wastes. 2. Faculty, instructors and TA’s should communicate unique safety concerns at the beginning of teaching labs prior to any experiments. The safety concerns should reflect the hazards posed by that experiment. 3. Responsible individuals over teaching labs should revise their teaching procedures regularly and review for possible hazards that can be eliminated. Any additions or deletions should be reflected in handouts provided. If people could use nitric acid + organic solvent visual for training purposes, this YouTube video seems...

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Beware drying nitrate-containing protic ionic liquids
Dec05

Beware drying nitrate-containing protic ionic liquids

“A batch of the protic ionic liquid pyrrolidinium nitrate exploded while drying it under reduced pressure at 110 °C, using a rotary evaporator with an oil bath.” So says a paper in Green Chemistry authored by researchers from KU Leuven and Umicore, both located in Belgium (Green Chem. 2013, DOI: 10.1039/c3gc41328d). While ionic liquids typically have low vapor pressures and high flash points, that doesn’t mean they’re hazard-free, as the documented experience indicates. KU Leuven chemistry professor Koen Binnemans and colleagues were investigating a series of pyrrolidium ionic liquids with different coordinating groups, one of which was nitrate. The researchers report: After stirring at room temperature for 4 hours, the remaining pyrrolidine, water and nitric acid were removed on a rotary evaporator under reduced pressure (16 mbar) at 70 °C. Heating of the flask on the rotary evaporator was done by means of a hot silicon oil bath. Not all of the water could be distilled off, and the temperature was increased stepwise to 110 °C. Suddenly an explosion occurred. The glass round-bottom flask was scattered and part of the hot silicon oil in the heating bath was blasted by the shock to the walls and ceiling in the neighborhood of the rotary evaporator. At the same time, a cloud of reddish-brown nitrogen dioxide gas was visible. Luckily, nobody was injured and there was only material damage. The explosion can be attributed to the strong oxidizing properties of concentrated nitric acid under the anhydrous conditions, resulting in a violent oxidative decomposition of the organic compounds. A search of the literature revealed that mixing of nitric acid with secondary amines like pyrrolidine has been reported to cause violent reactions. Clark described secondary and tertiary amines as hypergolic with nitric acid. If you need to dry a nitrate-containing protic ionic liquid, they recommend vacuum freeze-drying rather than heating. This also seems like an opportune time to remind people of what Prudent Practices has to say about nitric acid generally: Nitric acid is a strong acid, very corrosive, and decomposes to produce nitrogen oxides. The fumes are very irritating, and inhalation may cause pulmonary edema. Nitric acid is also a powerful oxidant and reacts violently, sometimes explosively [with] reducing agents (e.g., organic compounds) with liberation of toxic nitrogen oxides. Contact with organic matter must be avoided. Extreme caution must be taken when cleaning glassware contaminated with organic solvents or material with nitric acid. Toxic fumes of NOx are generated and explosion may occur. Please remember to separate nitric acid from organics in both storage and...

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Friday chemical safety round up
Nov22

Friday chemical safety round up

Chemical health and safety news from the past few weeks: Court watch On Nov. 20, UCLA chemistry professor Patrick Harran had a status check with the judge regarding felony charges of labor code violations that led to the death of researcher Sheharbano (Sheri) Sangji. The result of that status check was another status check scheduled for Jan. 10, 2014. Harran’s preliminary hearing concluded on April 26. We’re going on two years since charges were filed on Dec. 27, 2011, and five years since the Dec. 29, 2008, fire. On Nov. 1, former UC Davis chemist David Snyder was arraigned on felony charges of reckless disposal of hazardous waste, possession of a destructive device or explosive, possession of materials with intent to make a destructive device, and possession of firearms on university property. The charges relate to an explosion in his campus apartment nearly one year ago. Snyder’s preliminary hearing concluded on Oct. 10. Snyder is scheduled for a trial-setting conference on March 17, 2014, and a jury trial to start on March 24, 2014. Tweets of the month from @Free_Radical1: First synthesis lab of the semester, and 3 students not wearing goggles. Lab uses conc. phosphoric/sulfuric acid. Meh, vision is over-rated. — Free Radical (@Free_Radical1) November 11, 2013 Idea for post-lab question: do a Google Image Search for “sulfuric acid in eyes”, screen cap the first page of hits, email to TA. #tempting — Free Radical (@Free_Radical1) November 11, 2013 I think our safety committee would have an issue with 450 undergrads synthesizing TNT: http://t.co/xYphFEXxMh — Free Radical (@Free_Radical1) November 21, 2013 Came across a J Chem Ed lab where the students used lithium aluminum hydride. Um…yeah. And by “yeah”, I mean “no”. — Free Radical (@Free_Radical1) November 21, 2013 Other items of interest The president-elect of ACS, Diane Grob Schmidt, is currently the chair of the Division of Chemical Health & Safety NIOSH released new recommendations for controlling worker exposure to nanomaterials BioRAFT will hold a webinar on Proactive EHS Management & Communications on Dec. 12 Residents near an Allenco Energy oil field in Southern California have been complaining for three years about fumes from the site. At Sen. Barbara Boxer’s request, EPA investigators visited the site in October. “I’ve been to oil and gas production facilities throughout the region, but I’ve never had an experience like that before,” [EPA regional administrator Jared] Bumenfeld said. “We suffered sore throats, coughing and severe headaches that lingered for hours.” No word on what’s happened since. Also in California, state regulators are supposed to match hazardous material origin paperwork with what arrives at disposal sites. They don’t. “These so-called lost loads...

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