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MICROSCALE CHEMISTRY IN UNDERGRADUATE TEACHING LABORATORIES
Summary:
Beginning in 1989, the University of Michigan (U-M) Department of Chemistry began implementing microscale chemistry techniques in the undergraduate teaching laboratories. Microscale laboratory experiments reduce the amount of chemicals necessary to perform undergraduate chemistry experiments to a fraction of what was historically used.

In addition to decreasing the quantities of chemicals purchased and amount of chemical waste generated, microscale techniques have proven to be safer and more cost effective than traditional experiments.

Applicable Regulations
40 CFR Parts 260-268.

State of Michigan Act 451 Part 111.

Overview of Procedure
Microscale chemistry is a pollution prevention method that decreases the amount of chemical waste generated during laboratory experiments. This concept was first introduced by chemistry professors at Bowdoin College in Brunswick, Maine. Standard chemistry procedures are re-written for individual experiments and specialized microscale equipment is utilized to perform the work. In some cases, the amount of a particular chemical needed for an experiment has been decreased by as much as 99 percent. The U-M has implemented microscale chemistry in its undergraduate inorganic and organic teaching laboratories.

Waste Minimization Procedure
Due to the number of laboratory experiments that have been converted to microscale, it is not practical to detail the individual procedures. However, the following table presents a before and after comparison of the amounts of chemicals used, as well as the cost of those chemicals, for an Aldol Condensation experiment. These quantities represent the per student amounts.

Chemical

Traditional Quantity
(gm or ml)
Traditional
Chemical Cost
Micro Quantity
(gm or ml)
Micro Quantity
Chemical Cost
Acetone 5 $0.03 0.073 <$0.01
Ethanol 60 $0.60 4.1 $0.04
Benzaldehyde 5.3 $0.81 0.212 $0.03
Sodium Hydroxide 5 $0.19 0.24 $0.01
p-Anisaldehyde 5 $0.71 0.2 $0.03
p-Chlorobenzaldehyde 5 $0.36 0.2 $0.01
3,4-Dimethoxybenzaldehyde 5 $0.77 0.2 $0.03
2-Furaldehyde 5 $0.47 0.2 $0.02
1-Naphthaldehyde 5 $1.27 0.2 $0.05
  Total Cost* $5.21 Total Cost* $0.23

*All costs were obtained from the 1994/95 Aldrich catalogue.

Known Limitations
Due to the small quantities of materials used, it may not be possible to have enough "product" left at the end of an experiment to run a series of experiments. For example, experiment #1 might have generated a product that was used to run experiment #2, etc. However, in the typical teaching laboratory, the "products" typically have no value and are disposed of as waste.

Safety & Health Precautions/Personal Protective Equipment
Follow all applicable safety and health protocols and regulations as established by your institution.

Benefits
Microscale techniques in the laboratory:

  • Reduce chemical waste produced at the source;
  • Improve laboratory safety by decreasing the potential for exposure to chemicals and reducing the potential for fire/explosion hazards;
  • Improve air quality due to the greatly reduced volumes of solvents and other volatile substances used;
  • Reduce laboratory costs for chemical purchase and disposal;
  • Reduce the time required to perform experiments due to shorter chemical reaction times;
  • Decrease the amount of storage space necessary for chemicals; and
  • Encourage students to think about waste minimization.

Disadvantages
To begin teaching microscale techniques in the laboratory, the institution must purchase microscale equipment and textbooks. However, the costs can be recovered in a relatively short period of time due to savings realized on purchase and disposal costs of reduced quantities of chemicals.

Project Related Costs
The table below presents a per student comparison of traditional vs. micro chemical purchasing costs for the Chemistry 216 course at the U-M. The experiments were performed during the 1996 spring semester. All costs were taken from the 1994/95 Aldrich catalogue.

Experiment Traditional Cost Micro Cost
Acetanilide 0.46 $0.05
Adol Condensation $5.20 $0.23
Sodium Borohydride Reduction $0.16 $0.02
Electrophilic Aromatic Substitution $1.01 $0.02
Diphenylacetylene $0.99 $0.10
Tetrapheynlcyclopentadienone $2.11 $0.08
Total $9.93 $0.50

The purchasing cost of chemicals for performing microscale experiments is 99.5 percent less than for traditional experiments.

Disposal costs for the individual experiments were not calculated. However, the quantities of chemicals used for microscale experiments are typically less than one tenth the amount used in traditional macroscale experiments. Disposal costs should be reflective of this significant decrease.

 

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