Safety and Environmental Considerations - Fundamentals of Industrial Chemistry: Pharmaceuticals, Polymers, and Business - page 247

of material that is off-specification. It either needs to be sold at a discount
resulting in a financial loss or reworked at an expense to improve the quality.
In the worst case it must be disposed, which can be expensive. Clearly, the
business priorities are in concert with this principle of green chemistry.
Like safety, green chemistry makes good business sense. The reader may
wonder why all the fuss about green chemistry if it is something that might be
done anyway. The answer is one of focus. Just as an increased focus on safety
can lead to a decrease in accidents, the increased focus on green chemistry
can lead to improvements both from an environmental perspective and from
a business perspective.
In order to promote green chemistry, the U.S. Environmental Protection
Agency sponsors the Presidential Green Chemistry Challenge. The awards are
listed on the EPA website ( http://www.epa.gov/greenchemistry/index.html).
Some examples of past award winners are given here to illustrate the princi-
ples of green chemistry.
The 2012 Greener Reaction Conditions Award was won by Cytec Indus-
tries Inc. for the use of scale inhibitors for the heat exchangers used in the
Bayer process that converts bauxite ore to alumina. Alumina is primarily used
to make aluminum metal. Previously, the heat exchangers had to be taken
off-line to remove the scale with sulfuric acid. Scale inhibition resulted in
tremendous energy savings (green principle six) and in fewer cleaning cycles
which means less hazardous waste generation (green principle one).
The 2012 Designing Greener Chemicals Award went to Buckman Interna-
tional Inc. for the use of enzymes to make paper of improved strength and
quality. This enables higher usage of recycled paper, savings in the amount of
wood consumed, and lower energy usage (green principle six). The enzymes
are from natural renewable sources (green principle seven) and replace chem-
ical additives (green principle five). The 2011 Greener Synthetic Pathways
Award went to Genomatica for a microbe that makes 1,4-butanediol by fer-
mentation of sugar (green principle seven).
Many organic reactions require solvation, typically in organic solvents.
Organic solvents can create waste; some pose flammability concerns; and
others may be toxic or harmful to the environment. For cost, environmen-
tal, and safety reasons, water is a preferred solvent but many reactants are
insoluble in water precluding its use as a solvent. The 2011 Green Chem-
istry Academic Award was earned by Dr. Bruce Lipshutz of the University
of California, Santa Barbara. He designed a surfactant that, in water, formed
micelles which enabled many organic reactants to dissolve in the lipophilic
inside region of the micelle. They reacted in these regions, effectively using
water to replace organic solvents. This is a good example of green principle
five: The use of auxiliary substances (e.g., solvents, separation agents, etc.)
should be made unnecessary wherever possible and innocuous when used.