Skip to Main Content

Letters

April 13, 2009
Volume 87, Number 15
pp. 2-4

Chemical Safety Explosion Hazard

THE MERCK FROSST Center for Therapeutic Research would like to alert the scientific community of a potential explosion hazard associated with the reagent magnesium nitride (Mg3N2). We have been using this compound for direct primary amide formation from esters according to a recently reported protocol (Org. Lett. 2008, 10, 3623). This procedure, typically carried out in a glass microwave reactor vial, involves adding magnesium nitride to a solution of ester substrate in methanol at 0 ºC followed by sealing of the vessel. The mixture is then stirred at room temperature for one hour and heated at 80 ºC for several hours.

On at least two other occasions in our labs, reactions conducted in this manner have proceeded without incident. However, in a recent scaled-up application using 800 mg of an ester substrate, 1.3 g of Mg3N2 and 6 mL of methanol in a 20-mL thick-walled Pyrex tube sealed with a heavy Teflon screw cap and rubber O-ring, a violent explosion occurred approximately one minute after removal of the reaction vessel from the ice bath. This event occurred with a force sufficient to sever the metal holding clamp and completely shatter the thick-walled tube. Fortunately, no one was injured.

The published procedure calls for stirring in a room-temperature water bath for one hour prior to heating at 80 ºC. Immediately after the incident above, we contacted the authors of the original research paper. They informed us that the purpose of the water bath is to control a significant exotherm that accompanies the formation of ammonia from magnesium nitride during this stage of the reaction.

Because we were unaware of this at the time of our experiment, we had employed the commonly used practice of warming the reaction mixture to ambient temperature by simply removing the cooling bath. Under these circumstances, the putative exotherm would not have been sufficiently controlled.

Given the newly uncovered potential hazard associated with the use of this reagent, the published procedure should be followed exactly as written and only on a scale comparable with those reported in the original research paper. In addition, extreme care and precaution should be exercised by those who choose to use this protocol in the future.

Sheldon Crane
Kirkland, Quebec



The Joys And Trials Of Teaching

I AM A PH.D. CHEMIST from Columbia University who spent several years in the pharmaceutical industry in New Jersey but now teach AP Chemistry at the public Lowell High School in San Francisco. I agree with or have experienced just about everything "Head of the Class" covers (C&EN, Jan. 19, page 81). However, I do think the following reflects a problem with the American Chemical Society: "A Ph.D. chemist who wants to pursue a career as a high school teacher will be in good company. A quick search by C&EN turned up more than a dozen Ph.D. chemists at public and private high schools around the country."

A dozen or two people across the entire country are not "in good company." I think the article is drastically undercounting. For example, I wouldn't show up in the ACS database since I'm not an ACS member. I regretfully dropped my membership soon after leaving industry because it cost so much. It cost on the order of $140 per year with few direct benefits besides C&EN and the potential of a discount on the Journal of Chemical Education. I had been an ACS member as a college student and grad student because of relevancy and deep student discounts. When I worked in industry, not only was I paid well, but the company also paid for membership in one society.

Now that I am a public school teacher, the pay is less, membership costs are not covered, and there is no discount from ACS for K–12 teachers. Many aspects of my high school teaching job are not frustrating, but the high cost of ACS membership for K–12 teachers is. A full year's membership to the National Science Teachers Association, which is more directly relevant in many ways for K–12 teaching, costs $74, about half of the ACS membership cost, and also includes a member magazine and a discount for a highly relevant national conference.

If ACS wants to add to its database of Ph.D. K–12 teachers beyond the dozen or so now apparently in the entire U.S., I respectfully suggest it reduce the membership fees or provide a C&EN-only membership or do something else creative.

Bryan Marten
Albany, Calif.



I RECENTLY RETIRED at 69 after 10 years of teaching chemistry in a public high school, prior to which I had spent decades as an industrial chemist. I earned my credential while I taught through an alternative-certification program.

My teaching years were by far the most rewarding of my working life—and also the most demanding. The workweek was consistently 55 to 60 hours and involved most of my weekends, the students did not always want to learn, and no experience I ever had in the "real world" prepared me for finding that after I had closed the door at the bell I was now the lone adult in a roomful of judgmental adolescents.

Notwithstanding the first year, however, it was an experience I treasure.

Godfrey Crane
Las Cruces, N.M.



New Mission For Weapons Labs

TWO ARTICLES regarding the Department of Energy's weapons laboratories and new leadership illustrate that without decisive management there will be continuing loss of opportunity within DOE (C&EN, Jan. 5, page 24, and Jan. 12, page 32). Secretary of Energy Steven Chu's statements are well phrased, but what he doesn't say, or perhaps what he doesn't yet completely understand, is that the U.S. needs the three weapons laboratories to have a mission, not a collection of projects.

I resigned from my position in the Materials Science Directorate at Sandia National Laboratories (SNL) about 10 years ago to pursue a career in the private sector, in part because of this lack of a clear mission. Nothing in the Jan. 12 article or any comments from my friends who are still with SNL or DOE suggests that any of the recent energy secretaries have successfully redefined the mission of the national labs.

Therefore, perhaps one of Chu's responsibilities will be to define a new mission for the weapons labs that addresses the U.S.'s needs and responsibilities, that is a coordinated effort, and that will create jobs and "repower" America. Basic research may be a part of this new mission, but Los Alamos would never have built an atomic weapon through investment in basic energy sciences without a mission.

Given the previous lack of success in redefining a sustaining mission, I will propose one: Fund the three weapons laboratories to compete against each other in a race to design a nuclear technology that produces electricity for less than the price achievable with coal-fired power plants. The generation cost must encompass the entire fuel cycle, including waste processing and eventual storage. Because the cost of clean electricity is, or will be, a basic unit of commerce, if the labs are successful, the cost of energy will be less in the U.S. than in any other country. I can't imagine a more strategically competitive—or a more capitalist—approach to energy generation.

Such a mission may appear ludicrous, as current light-water reactors are massively expensive and the total fuel cycle cost has yet to be completely captured. However, I clearly remember how Edward Teller promoted his ideas for mass-produced, inexpensive, highly efficient, low-waste (per megawatt), secure underground reactors when he lectured at Sandia in the early 1990s. Some of his ideas have been further refined (Nucl. Technol. 2005, 151, 334). This article's abstract suggests a design for a reactor that would operate without refueling for 200 years.

Why not take this a step further to a 1,000-year, mass-producible reactor that would provide inexpensive, near-zero-waste energy (on a per MW basis)? A competition to design and build such a reactor would be a defining mission for the weapons laboratories that would address climate change, nuclear waste minimization, and low-cost electricity generation, as well as competitiveness and job creation. Perhaps there could be a new chapter in Teller's legacy, if only there were the political will to change the direction of the weapons laboratories to clean, efficient, precompetitive nuclear energy generation.

Paul Cahill
Dayton, Ohio



Who's Teaching Whom In Chemistry?

THE ARTICLE describing the important role lecturers successfully play in several chemistry departments conveyed a very positive image of these non-tenure-track educators (C&EN, March 9, page 32). At the same time, however, members of the academic community are expressing concern about the apparent increase in the number of non-tenure-track and temporary faculty who are teaching undergraduates.

This increase in the use of lecturers in U.S. academic institutions was documented in an article titled "Tracking the Invisible Faculty" in the Dec. 15, 2006, issue of the Chronicle of Higher Education. To better define "who's teaching whom" in chemistry, the ACS Committee on Professional Training (CPT) will conduct a survey this fall on the teaching responsibilities of faculty and staff in chemistry departments. CPT anticipates that the results of this survey will provide the first detailed picture of the types of faculty and staff students are seeing in undergraduate chemistry classrooms and laboratories.

Cynthia Larive, chair, CPT
Riverside, Calif.

Suzanne Harris, vice chair, CPT
Laramie, Wyo.



Chemical & Engineering News
ISSN 0009-2347
Copyright © 2011 American Chemical Society