Green Laboratories: Facility-Independent Experimentation - ACS

C h a p t e r 10

Green Laboratories: Facility-Independent Experimentation

Downloaded by UNIV OF PITTSBURGH on December 25, 2015 | http://pubs.acs.org Publication Date: April 22, 2009 | doi: 10.1021/bk-2009-1011.ch010

Kenneth M. Doxsee Department of Chemistry, University of Oregon, Eugene, OR 97403

By virtue of its focus on the reduction of intrinsic chemical risk rather than solely on minimization of exposure, Green Chemistry allows for laboratory investigations in settings that would be inappropriate for "conventional" chemical experimentation. The benefits of a Green curriculum are numerous, ranging from enhanced safety and cost savings to the facilitation of the (re)introduction of experimental chemistry, particularly at the K-12 and community college levels, where facility limitations have often curtailed laboratory investigation. A Green curriculum thereby promises enhancement of both the numbers and the diversity of students gaining knowledge of the practice of modern chemistry.

Overview Many generations of students have euphemistically "had the opportunity" to carry out chemical experimentation in poorly equipped and inadequately ventilated spaces serving as teaching laboratories. However, modern laboratory safety procedures wisely limit such practice and its attendant risk of student exposure to hazardous chemicals. Recognizing reduction of exposure as an obvious means of reducing the risk of chemical investigations, most institutions attempt to provide well-ventilated laboratories, often having students perform all of their manipulations within the confines of efficient fume hoods. Many have also converted to microscale experimentation in order to further limit the © 2009 American Chemical Society In Green Chemistry Education; Anastas, Paul T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2009.

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148 likelihood of exposure to significant amounts of hazardous substances. Even in microscale experimentation, however, significant volumes of solvents are often evaporated in the fume hoods, and even small quantities of particularly hazardous substances can still present substantial risk upon exposure.


Risk Reduction via Minimization of Exposure Unfortunately, avoidance of risk by reduction of exposure through use of "environmental controls" such as fume hoods presents several significant problems. Foremost among these is the fact that environmental controls can fail to protect students from intrinsically hazardous substances. How many of us have seen a student working literally in a fume hood, with head and shoulders inside the confines of the hood while adjusting an apparatus or adding solvent to the top of a tall chromatography column? (Indeed, how many of us have done this ourselves?) This all-too-common practice, of course, effectively converts the fume hood from a protective device into a fume concentrating device for the student. In addition, fume hoods suffer from the potential for outright failure due to obstruction of air flow (e.g., by books, apparatus, or bottles, or by paper towels sucked into ventilation lines), to loss of electrical power, or to inefficient removal of particularly dense vapors (e.g., bromine). Add to this picture the fact that fume hoods merely release vapors to the atmosphere atop the laboratory building, where building air intakes may be sited and upon which construction and maintenance workers may tread, and one may quickly conclude that reliance on fume hoods to reduce risk is significantly problematic. A n E P A Survey (/) provides typical observations in these regards. "... a survey of the classrooms used by the high school science staff indicated that less than 40% of these rooms were equipped with chemical fume hoods. In addition, we found that none of the middle school science rooms or the secondary level art studios had been equipped with chemical fume hoods to provide additional mechanical exhaust. As a result, the construction of the individual classrooms limited what activities or materials could be safely used by the occupants without jeopardizing indoor air quality. During our inspection, we noted that most of the fume hoods were in a state of serious disrepair. We found units that were missing interior panels and covers and as a result leaked contaminants. We found hoods with malfunctioning or inoperative ventilation fans. We also observed hoods vented through duct work that was perforated. Finally, we also found

In Green Chemistry Education; Anastas, Paul T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2009.

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that all the hoods serving the science area were constructed so that the hood exhaust was located adjacent to the hood intake. As a result materials evacuated by the hood could be reentrained by the intake and brought back into the classroom." A l l these concerns aside, fume hoods as environmental controls in the teaching laboratory represent a tremendously expensive approach to the avoidance of chemical risk. Typical university-level chemical teaching laboratory renovation or construction projects run into the many millions of dollars, with a substantial percentage of this sum devoted to the purchase and installation of fume hoods for each student laboratory worker. Once installed, the air handling costs rapidly begin to mount, not only through the electrical costs of the air handling equipment, but also with the fume hoods quickly and efficiently removing heated (in cold climates) or cooled (in warm climates) laboratory air and requiring the cost-intensive heating or cooling of "makeup" air. While the costs of the latter are not always recognized, they can be daunting. Illustrative is a recent study (2-4) of a University of California prototype energy-efficient fiime hood design, which concluded that the new design, which reduced the airflow to 30% of that for a typical hood installation, "could save 360 gigawatt-hours of electricity in California, and 2,100 gWh in the United States." What cost savings would this reduction represent? "At $0.08 per kWh, the annual electrical savings per hood is about $1,000 (4)." On a more global level, the estimated energy savings i f such reduced-flow hoods were adopted US-wide would be equivalent to approximately half the annual power output of the Bonneville Dam, on the Columbia River in the Pacific Northwest.

Green Chemistry: Reduction of Intrinsic Risk What, then, does one do if one wishes to provide students with the opportunity to carry out chemical investigations in a laboratory setting? The answer, of course, is suggested by the appearance of this chapter in a volume dedicated to the concepts of Green Chemistry. Simply put, Green Chemistry approaches the issue of risk reduction not through minimization of exposure, but rather through reduction of intrinsic chemical hazards. By reducing the intrinsic hazards of the chemicals, solvents, and reagents being used, Green Chemistry reduces or eliminates the risk, even in the event of exposure, since exposure to an innocuous substance does not represent risk. The advantages of the Green Chemistry approach to risk reduction are immediately obvious and realizable. Students enrolled in the organic chemistry laboratory program at the University of Oregon carry out bench-top experimentation in a laboratory that is strikingly simple in its design (Figure 1), comfortable and inviting due to its openness and low ambient ventilation noise


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levels, and safe not only given the intrinsic safety of the materials being used but also given the ease with which supervisory staff can observe all student workers. Additionally, the laboratory's open sight lines foster the free exchange of information among students. The architects and designers of this laboratory frequently marvel at the high level of student comfort and joy evident in this lab, particularly in contrast to the high student stress levels more frequently encountered in such a pre-professional class.

Figure 1. The Green laboratory at the University of Oregon. (See page 4 of color insert.)

Laboratory Experience in Non-Traditional Settings Although not an originally intended consequence of conversion to a Green curriculum, we rather quickly recognized that the intrinsic safety of Green Chemistry allows for experimentation in facilities that might not otherwise be viewed as viable laboratory settings. The extreme of this flexibility, perhaps, has been demonstrated by presentation of Green laboratory workshops in conventional meeting rooms in several resort hotels, including workshops held in conjunction with the 2 2 Mexican Congress for Chemical Education (Ixtapa, Guerrero, Mexico, September, 2003) and with the 4 International Meeting on Chemistry Teaching at College and Pre-College Level (Merida, Yucatan, Mexico, November, 2005). A typical scene from the Ixtapa workshop is depicted in Figure 2, in which student and faculty participants from throughout the Americas are seen working in a conventional meeting room, complete with blue cloth table coverings and floor-length draperies, clearly the antithesis of the typical organic chemistry teaching laboratory! Figure 3 shows a participant carrying out a solvent-free aldol reaction (5) while seated in a comfortable chair, again hardly a standard laboratory setting. Within ten minutes of conclusion of the Merida workshop, the meeting room was in use as a lecture hall by a group of some thirty meeting attendees, not one of whom noted any air quality issues. nd

th



151 Contrast this situation with the not uncommon lingering chemical odors in a conventional teaching laboratory! The concept of carrying out organic chemical experimentation in a hotel room is, of course, extreme. Or is it? The sad reality is that many, perhaps most, of the educational settings in which one would hope to provide the opportunity for hands-on chemical experimentation are seriously under-equipped to allow work with hazardous substances. In grade schools, middle schools, and high schools, in community colleges, and in colleges and universities, and particularly in developing nations, we are more likely to encounter poorly ventilated laboratories than we are state-of-the-art facilities. With many studies showing that interest in the sciences is highest in young children and progressively decreases with educational level (6-9), and other studies highlighting the value of hands-on experience and experimentation in retaining student interest in the sciences (70), the all-too-common inability for schools to offer laboratory experience given the lack of suitable, safe facilities demands attention.

Figures 2 and 3. Organic experimentation in a hotel meeting room. (See page 4 of color insert.)

Green Chemistry, by permitting experimental chemistry to be performed in settings perhaps more closely approximating hotel meeting rooms than state-ofthe-art laboratories, allows the reintroduction or revitalization of laboratory curricula throughout the full range of educational institutions, K-12 and beyond. The longer-term impacts of this change, in terms of the very face of chemistry, are staggering. Consider the implications at the community college level alone a recent analysis (77) reports nearly 1,200 such institutions in the United States, enrolling over eleven million students, representing 45% of all US undergraduate students and 45% of first-time freshman students. Who are the students enrolled in community colleges? • •

32% are 30 years of age or older; 46% are 25 years of age or older. 59% are women.


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85,000 are international students.

•

47% of black undergraduate students are enrolled in community colleges; 55% of Hispanic students, 57% of Native Americans, and 47% of Asian/Pacific Islanders. 50% of new nurses, and nearly 80% of emergency medical technicians are community colleges graduates.


•

Given fiscal realities, including historic under-funding and a need to maintain low tuition rates in order to ensure accessibility, many community colleges suffer from lack of availability of quality laboratory space. Can we afford to ignore these students, representing one of the greatest single sources of ethnic, gender, and age diversity, by not offering the opportunity to carry out state-of-the-art experimentation in the sciences? How many more students are impacted by the lack of laboratory facilities at the K-12 levels? How many more well-trained scientists would there be if we did not accept the inevitability of loss of interest in science with increasing grade level?

The Role of Green Chemistry in (General) Education Is there a down side to Green experimentation? Critics occasionally object to the Green Chemistry curriculum, feeling that, by focusing on work with safe chemicals and procedures, students will not be properly trained to work with hazardous materials (12). We find this argument specious on a number of grounds. We do envision a future in which there may be no need for hazardous substances, and we do not see a problem with instilling this hope in the next generation of scientists, rather than pessimistically assuming a future in which chemical hazards are a given. As we work toward this vision, students trained in Green Chemistry learn about "peripheral" subjects such as toxicology and environmental chemistry. In the process, they develop the necessary tools to recognize and critically assess health and environmental hazards rather than following the common advice in traditional laboratories to "treat all chemicals as hazardous." In addition, "Green" is a relative term, and although some experiments are appreciably less hazardous than those they have replaced, they may still offer students the opportunity to work with things that are not completely safe. Finally, we must recognize our clientele - the vast majority of students enrolled in chemistry laboratory courses will, in fact, not become practicing chemists, but rather doctors, nurses, pharmacists, dentists, or any of myriad other professions. Most of them will not work with hazardous substances. They can be taught the scientific method and laboratory techniques with safe substances. Is it reasonable to "test" proper technique by seeing whether a student can successfully avoid being exposed to a known carcinogen? Importantly, the intrinsic interest of Green Chemistry also is attracting students


153 who otherwise would be highly unlikely to consider chemistry courses. This new audience of students, who may go on to become lawyers, journalists, business owners, or politicians, will enter their chosen professions with a firm foundation in chemistry.


Summary Green Chemistry reduces risk through reduction of the intrinsic hazards associated with a chemical or process, not solely through the reduction of exposure. Given its intrinsic safety, Green experimentation does not require special environmental control devices, with their concomitant installation and operation costs as well as the potential of accidental exposure as a result of either misuse or equipment failure. As a result, Green Chemistry allows for experimentation in a wide variety of settings, allowing the reintroduction of real experimentation as a key component in the scientific education of students at all educational levels. By allowing for enlivening of the science curriculum through laboratory investigation, Green Chemistry may play a key role in the education and training of a diverse future generation of scientists and citizens, fully reflective of the face of modern society.

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Green Laboratories: Facility-Independent Experimentation - ACS

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