SCIENCE & TECHNOLOGY
MAKING EXPLOSIVES IN THE LAB
XAVER STEEMANN AND NORBERT MAYR
One of those rules is that students must fill out a form before starting a reaction, describing the chemistry they’ll do and the hazards of any chemicals involved. Shreeve also implemented a buddy system in her group, requiring students to discuss experiments and safety considerations both with Researchers IMPRESS ON STUDENTS the importance of safety her and with their lab buddy. “It gets people JYLLIAN KEMSLEY, C&EN WEST COAST NEWS BUREAU talking to each other, makes people aware of what others in the group are doing, and helps in identifying flaws or dangers in the “If you work with energetic materials, procedures,” Shreeve tells C&EN. LABORATORY SAFETY is a concern for which for us are mainly compounds that Thomas M. Klapötke, a chemistry proall chemists, but it takes on a whole new have relatively weak bonds, then you have fessor at Ludwig Maximilians University, meaning when one is synthesizing highly to assume that they can be hazardous,” Munich, has perhaps the most rigorous apenergetic or explosive materials. DesMarteau says. “So everything you do is proach to training students in the art of synDarryl DesMarteau, a chemistry probuilt around that [assumption].” The most thesizing energetic compounds. Klapötke’s fessor at Clemson University, knows the important thing when handling energetic research program focuses on creating new dangers all too well. A laboratory accident materials, he notes, is to work with small materials to replace the nitramines RDX and when he was a graduate student led to the quantities. His students and postdocs work HMX, commonly used military explosives. loss of his left hand and part of his right on vacuum lines that allow them to maIn Klapötke’s lab, undergraduate students hand. During an experiment, he had acnever handle energetic matericumulated about 200 g of F2SO3, als. Starting at the master’s level, which exploded unexpectedly. “I students coming into the lab must didn’t even want it but decided to first synthesize no more than 250 save it,” DesMarteau says. “That mg of a secondary explosive, a turned out to be a bad decision.” compound such as TNT that is What exactly happened in very energetic but has a high actithe lab that day is still a bit of a vation barrier. They then characmystery, but hydrocarbons can terize the sample, determining the sometimes initiate a chain decomimpact, friction, and electrostatic position of peroxygen and oxygensensitivity of the material. halogen compounds. DesMarteau Having successfully completed now believes that a hydrocarbon that synthesis, a student then contaminant set off the F2SO3 will synthesize and characterize explosion. The people in the lab a small amount of a primary ex“should have known better, but we plosive—such as lead diazide—a didn’t,” he says. “We just assumed compound that is less energetic that the stuff was okay if handled TESTING A nipulate and characterize small than a secondary explosive but properly, and that assumption was wrong.” new explosive amounts of compounds—at is more sensitive and carries a Working with highly energetic materimaterial prepared most a few hundred milligrams. higher risk of explosion. als can be a challenge even for seasoned in Klapötke’s lab Jean’ne M. Shreeve is a researchers, never mind inexperienced detonates when heated rapidly to professor of chemistry at the students. Something as innocuous as a THIS APPROACH of practice syn700 ºC. University of Idaho, and one bit of material caught on the threads of a theses gives students the feel for focus of her research program is screw-top vial, for example, can lead to an the materials they might handle, developing high-nitrogen comexplosion in a student’s hands if that mateKlapötke says. In particular, if pounds—such as triazole and tetrazole rial is sensitive to friction. DesMarteau and they’re synthesizing a new, unknown comderivatives—for explosives and propelothers in the field put a high priority on pound, they have to treat it as if it’s a primary lants. She says that her group collectively investing the time to develop and enforce explosive. It also gets students used to workhas put together basic guidelines regardlab safety protocols, promote communicaing in full protective gear: a helmet with face ing appropriate lab safety, and she discusstion in laboratories, dispose of materials shield, leather jacket, and grounded shoes. es those rules with prospective students promptly, and even cull insufficiently careOnly after students have completed a one-on-one before they join the group. ful students from groups. master’s degree and are working toward For his part, more than four decades after his accident, DesMarteau still works with fluorine compounds. A major focus of his group now is synthesizing fluorinated electrolytes for lithium batteries and fuelcell membranes. He says laboratory safety is an important part of his group’s ethos.
“Sometimes people do something stupid and you can’t take the risk that they will do it again.”
WWW.C E N- ONLI NE .ORG
22
JANUARY 7, 20 0 8
SAFETY FIRST A student
in Klapötke’s group wears a Kevlar suit to set up an explosion performance test.
a major issue no matter what kind of chemistry you’re doing, but for us it’s particularly important,” Shreeve says. It’s critical to impress on students not only to store compounds safely while they’re studying them, she says, but also to store them no longer than necessary. Both Klapötke and DesMarteau have refused to work with students who may be a safety hazard. Klapötke declined to let a student advance to Ph.D.level work after the student repeatedly scaled up syntheses without permission. DesMarteau asked a student to leave after the student let their spouse use the group’s COU RTESY OF THOM AS KLA PÖTKE
a doctorate do they get to synthesize unknown materials. As in Shreeve’s group, students must fill out a form outlining the proposed reactions, quantity of materials, known safety hazards, and disposal procedures for every experiment. Klapötke or a senior member of the group must approve each proposed experiment. Syntheses are normally done only at the 150- to 250-mg scale, and larger quantities are prepared only after compounds are fully characterized and their properties are well-understood. Any synthesis larger than 5 g is done in the company of Klapötke or a senior member of his group. At the end of the day, safe disposal of compounds and waste products is another important consideration. “Waste disposal is
vacuum line to pump off an organic solvent, and the next day the residue caused another student’s compound to explode. No one was hurt, but “sometimes people do something stupid and you can’t take the risk that they will do it again,” DesMarteau says. One overarching safety concern among investigators of highly energetic materials is loss of knowledge and experience as faculty age. Funding for projects is scarce, they say, and so younger researchers aren’t maintaining and developing the skills they may have learned as graduate students. “Once that knowledge is gone it’s very difficult to get it back,” Klapötke says. “I was on a National Research Council committee recently dealing with energetics, and this issue came up over and over again,” Shreeve tells C&EN. “The people who make their living in this field are dying off, and who’s going to take their places?” She says that there is some effort to encourage funding agencies to support research in the area of energetic materials, preserving not only scientific knowledge but the ability to pursue new research safely. ■
FREE Drug Development Resources for the Academic/Not-for-Profit Investigator On a competitive basis, the NIH offers certain critical resources needed for the development of new small molecule therapeutic agents. The NIH-RAID Pilot is not a grant program. Successful projects will gain access to the government’s contract resources. Services include: Synthesis in bulk of small molecules; Synthesis of oligonucleotides; Chemical synthesis of peptides; Scale-up production; Development of analytical methods; Isolation and purification of natural products; Pharmacokinetic/ADME studies including bioanalytical method development; Development of suitable formulations; Manufacture of phase I drug supplies; Range-finding initial toxicology; INDdirected toxicology; Product development planning and advice in IND preparation. The program also is open to non-U.S. applicants. Applications are received electronically through Grants.gov. Ideas arising solely from a corporate source without academic collaborators are not eligible.
R EQUEST MOR E AT ADI NFONOW.ORG
R EQUEST MOR E AT ADI NFONOW.ORG
National Institutes of Health Rapid Access to Interventional Development
NIH-RAID Pilot Program Office 301-594-4660;
[email protected] http://nihroadmap.nih.gov/raid WWW.C E N- ONLI NE .ORG
23
JANUARY 7, 20 0 8
