v>EPA
Why Focus on .
Research in Organic
Chemistry?
What environmental
concerns are
associated with the
synthesis of
chemicals?
What is the
Chemical Design
Project?
What is EPA doing
to encourage
academic research-
in this area?
United States
Erwironmantal Protection
Agency
Office of Pollution Prevention
and Toxics
Washington, DC 20460
EP A744F-33-005
April 1333
Design for the Environment
Chemical Design Project
The moment a chemist puts pencil to paper to design a synthetic sequence for
a chemical product, he also intrinsically makes decisions about whether that
sequence will use or generate hazardous substances that require treatment,
recycling, transportation or disposal. There are literally hundreds of different
chemical reactions that can be utilized to construct a desired organic chemical,
some which provide more pollution prevention benefits than others. With
proper forethought and analysis, organic chemists can avoid many of the
environmental problems and liabilities chemical producers face before they
arise.
The traditional approach to chemical design has been to search for synthetic
pathways or reaction steps that produce the greatest yield at the least cost.
Many approaches that produce high yields, however, also generate toxic by-
products or use high-risk substances as feedstocks, solvents, and catalysts.
When these chemicals are used or produced in large volumes in their industrial
applications, the associated cost to human health and the environment can be
high. The development of alternative synthetic pathways which avoid or
reduce the use of toxic chemicals will provide chemical producers with
powerful tools for pollution prevention. Companies can save money by
lowering disposal costs, avoiding regulatory problems and reducing health
hazards for employees.
EPA's Chemical Design Project aims to change the way organic chemists
approach the design of synthetic pathways for chemical production. EPA is
encouraging consideration of alternative synthetic pathways through: (1) grant
awards to academic institutions; (2) discussion at national symposia; and (3)
use of computer programs which assist in the design of chemical pathways.
In 1992, EPA awarded six grants to fund basic research projects which
consider environmental impacts, and not just yield, in the design of chemical
synthetic pathways. Now EPA is joining forces with the National Science
Foundation (NSF) through a memorandum of understanding to award
approximately two million dollars in additional grants. By fostering this kind
of basic research in organic chemistry, EPA and NSF hope to bring about a
paradigm shift in the way chemists, in both academia and the chemical
industry, think about the design and manufacture of chemicals.
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What kinds of research constitute alternative synthesis?
The six research projects funded by the 1992 EPA grants provide excellent examples of novel approaches
that minimize or eliminate hazardous feedstocks, catalysts, solvents, or by-products.
Replacing Heavy Metal Catalysts
Catalysts are of utmost importance to the industrial
production of chemicals, yet they often have toxic
components, including silver and mercury, that
contribute to hazardous waste disposal problems when
discarded. The University of Connecticut's research
project, directed by Dr. Gary Epling, is considering
the effectiveness of a more environmentally benign
alternative: molecules that can be activated by
inexpensive artificial light sources. This research is
developing large-scale methodology for the light-
induced cleavage of dithianes and benzyl ethers,
reactions commonly used in the dye industry.
New Synthesis of Styrene
Styrene is a high volume chemical that has hundreds
of applications in everyday products. UCLA's
research project, lead by Dr. Orville Chapman, is
developing an alternative synthetic method for the
manufacture of styrene. The proposed method uses
less toxic chemicals as substitutes for problem
environmental chemicals including the known
carcinogen benzene, which presently serves as a basic
feedstock of styrene.
Visible Light to Replace the Friedel-Crafts
Reaction
Dr. George Krauss is leading Iowa State University's
research into an innovative photochemical alternative
to the Friedel-Crafts reaction, one of the top ten most
used chemical reactions. The use of visible light as a
mechanism for initiating the reaction could provide an
economic incentive for replacing a well-known
reaction step that uses toxic pollutants.
Elimination of Tin Based Catalysts
Dr. Barry Snider of Brandeis University is working
to reduce the hazard posed by radical cyclization
reactions which use highly toxic tin-based catalysts
by substituting a recyclable catalyst that will not
accumulate in waste effluents. The improved
synthetic selectivity of this approach should result in
greater yields of the target compound and fewer
impurities that enter the waste stream.
Replacing Benzene with Simple Sugars
Benzene is a basic ingredient in many commercially
important industrial chemicals including
hydroquinone and benzoquinone. Although benzene
is an extremely useful petrochemical, it is a known
carcinogen and problem pollutant. Dr. John Frost oi
Purdue University is working on a new,
environmentally benign method of producing
hydroquinone and benzoquinone, that replaces the
use of benzene. This method utilizes a genetically
engineered bacterium that produces quinic acid frorr
D-glucose. The quinic acid is converted into
hydroquinone and benzoquinone under more
environmentally safe conditions.
Alternative for Toxic Solvents
Dr. James Tanko at the Virginia Polytechnic Institu
and State University is evaluating the utility of
supercritical carbon dioxide (carbon dioxide betwee
liquid and gaseous states) as the solvent for certain
free-radical chemical reactions. This approach may
provide an economic incentive for private industry
make the transition away from the currently used
problem solvents such as chlorofluorocarbons,
carbon tetrachloride and benzene.
Is there additional information available on the Chemical Design Project?
For more information contact EPA's Pollution Prevention Information Clearinghouse (202) 260-1023 or
Paul Anastas, Economics and Technology Division (TS-779), Office of Pollution Prevention and Toxics,
U.S. EPA, 401 M Street, S.W. Washington, D.C. 20460; (202) 260-2659.
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