CHAPTER 1
CHEMISTRY, GREEN CHEMISTRY, AND
ENVIRONMENTAL CHEMISTRY
From Green Chemistry and the Ten Commandments of
Sustainability, Stanley E. Manahan, ChemChar Research,
Inc., 2006
manahans@missouri.edu
1.1. Chemistry is Good
• All matter is chemical; we are chemical
• The human body is a complex chemical factory
• Green Chemistry seeks to present a body of chemical
knowledge from the most fundamental level within a
framework of the relationship of chemical science to
human beings, their surroundings, and their
environment.
• Green chemistry is the practice of chemistry in a
manner that maximizes its benefits while eliminating
or at least greatly reducing its adverse impacts
Good Things from Chemistry
• Pharmaceuticals that have improved health and
extended life
• Fertilizers that have greatly increased food
productivity
• Semiconductors that have made possible computers
and other modern electronic devices
The Downside of Chemistry
• Pollutants
• Toxic substances
• Nonbiodegradable plastic containers
These have resulted in harm to the environment
Major Categories of Chemistry
• Inorganic chemistry deals with materials composed of
most elements other than carbon (and includes a few
carbon compounds)
• Organic chemistry deals with carbon-containing
materials, most having carbon-carbon bonds
• Physical chemistry involves the underlying theory and
physical phenomena that explain chemical processes
• Biochemistry is the chemistry of living processes
• Analytical chemistry is the identification and
quantification of chemical species, often at very low
levels
The Old Attitude:
“By sensible definition any by-product of a chemical operation for
which there is no profitable use is a waste. The most convenient,
least expensive way of disposing of said waste—up the chimney or
down the river—is best.”
From American Chemical Industry—
A History, W. Haynes Van Nostrand
Publishers, 1954
Chemists and Chemistry are Part of the
Solution
• Chemistry is required to deal with environmental
problems and challenges to sustainability
• Of all professionals, chemists are the best qualified to
understand environmental problems from the misuse
of chemistry
• The practice of environmentally beneficial chemistry
is not a burden, but rather an opportunity that
challenges human imagination and ingenuity
1.2. THE ENVIRONMENT AND THE FIVE
ENVIRONMENTAL SPHERES
The Atmosphere
• Very thin, most within several kilometers of Earth’s
surface
• Provides oxygen for animals and other organisms,
carbon dioxide and nitrogen for plants
• Vital protective function
• Stratospheric ozone protects against harmful
ultraviolet
• Stabilizes Earth’s temperature by re-absorbing
outgoing heat as infrared radiation
• Conduit for fresh water by way of the hydrologic cycle
The Hydrosphere
• More than 97% in oceans
• Most of the remaining fresh water is ice and snow in
polar ice caps and glaciers
• Small fraction of water in atmospheric water vapor
• Fresh water on the surface in lakes, reservoirs, and
streams and as groundwater in underground aquifers
The Geosphere
• Includes all rocks and minerals
Soil, where present
Crust, several km or less
Lithosphere, 50-100 km
Molten rock
• The crust is the part of the geosphere that is available
to interact with the other environmental spheres and
that is accessible to humans
The Biosphere
• All living organisms
• Most found in a very thin layer at the interface of the
geosphere and atmosphere and in the hydrosphere
• Involved with the geosphere, hydrosphere,
atmosphere and even anthrosphere through
biogeochemical cycles
• Biogeochemical cycles involve important life
elements including carbon, nitrogen, and phosphorus
The Anthrosphere
• Strong interactions with other environmental spheres
• Cultivation of land modifies the geosphere
• Diversion and use of water affects the hydrosphere
• Emission of particles, acid gases, organics,
greenhouse warming carbon dioxide
• Perturbation of biogeochemical cycles
• Entering anthropocene era
Environmental Chemistry
Environmental chemistry is the study of the sources, reactions,
transport, and fates of chemical species involving all environmental
spheres
SO 2 + 1/ 2 O2 + H2 O
H2 SO 4
H 2SO 4
SO 2
S(coal ) + O 2
SO 2
H2 SO 4, sul fates
Aquatic Chemistry
Gas exchange with the atmosphere
Atmospheric Chemistry
Gas-phase molecules can absorb
photons to produce excited species
O*
O
H3C C H + h H3C C H
.
H3C
.
That can dissociate to
produce reactive radicals H3C + O C H
.
.
+ O2  H3COO
NO
.
H3CO
SO 2, O2
+ NO2 Radicals in turn participate in
a number of chain reactions.
Reactions also occur
inside water droplets
H2SO 4
And on particle
surfaces.
Chemistry of the Geosphere and Soil
Chemistry of the Biosphere and
Toxicological Chemistry
Toxicant
... + ...
Toxic
effect
Organism
Toxicological
chemistry
Toxicology
Chemistry of the Anthrosphere within a
Framework of Industrial Ecology
Materials
processing and
manufacture
Primary
materials
producer
Energy
Waste
processor
Consumer
1.4. Environmental Pollution
Awareness from
• Silent Spring, Rachel Carson, 1962
• Approximately 10,000 deformed children from
thalidomide
• Visible air pollution
• “Dead” bodies of water
• Love Canal around 1970
Command and Control Approach
Emphasizing End-of-Pipe Treatment
Measures
1.5. What is Green Chemistry?
Green chemistry is the sustainable practice of chemical science and
manufacturing within a framework of industrial ecology in a manner
that is sustainable, safe, and non-polluting, consuming minimum
amounts of energy and material resources while producing virtually
no wastes.
Green Chemistry is Sustainable
• Economic: At a high level of sophistication, green
chemistry normally costs less in conventional
economic terms (as well as environmental costs) than
chemistry as it is traditionally practiced
• Materials: By efficiently using materials, maximum
recycling, and minimum use of virgin raw materials,
green chemistry is sustainable with respect to
materials
• Waste: By reducing insofar as possible, or even
totally eliminating their production, green chemistry is
sustainable with respect to wastes
1.6. Green Chemistry and Synthetic Chemistry
Synthetic chemistry involves finding ways to make new
chemicals and new ways to make known chemicals
• Use existing feedstocks, but make them by more
environmentally benign processes
• Use other feedstocks made by environmental benign
processes
Subsitute chemicals made
by envir onmentally benign
processes
Environmentally benign
synthesis of existing
feedstocks
Chemical
Existing chemicals synthesis process
Products
Yield and Atom Economy (1)
Typical reaction with less than 100% yield
and with byproducts
Yield and Atom Economy (2)
1.7. Reduction of Risk: Hazard and Exposure
Risk = F{hazard  exposure}
• Reduced exposure: The hazard remains, but
exposure to it is reduced, such as by wearing safety
goggles around an eye hazard (a command and
control approach)
• Reduced hazard: The hazard is diminished or
eliminated at its source; measures still may be taken
to reduce exposure to remaining hazard
• Hazard exposure is less costly because costs of
protective measures may be reduced
1.8. The Risks of No Risks
• Refusal to take any risks can cause scientific and
economic progress to stagnate
• Example: Refusal to take the risks of thermally
treating wastes (hazardous waste incineration) can
lead to waste accumulation, or important industrial
processes making the waste may be ceased
• Example: Unwillingness to take risks involved with
nuclear energy can lead to greenhouse warming from
using fossil fuels or to economic stagnation from
energy shortages
1.9. Waste Prevention
• Costs of engineering controls, regulatory compliance,
personnel protection, wastewater treatment, and safe
disposal of hazardous solid wastes have become high
costs of doing business
• Waste prevention applying the principles of green
chemistry and industrial ecology is a much better
approach
1.10. Twelve Principles of Green Chemistry (1)
1. It is better to prevent waste than to treat or clean up
waste after it is formed
2. Synthetic methods should be designed to maximize the
incorporation of all materials used in the process into
the final product
3. Synthetic processes should avoid use and generation of
toxic and environmentally damaging substances
4. Chemical products should be as effective as possible
but with minimum toxicity
5. Auxiliary substances, such as solvents and separation
agents should be avoided or should be as innocuous as
possible
6. Energy requirements should be low; extreme
temperatures and pressures should be avoided
Twelve Principles of Green Chemistry (2)
7. Raw materials should be from renewable sources
8. Derivatization for blocking groups protection and
property modification should be avoided
9. Catalytic reagents should be used when possible
because of their specificity and minimum amounts
required
10. Chemical products should be designed so that at the
end of their lifetime they readily break down to
harmless products
11. The best analytical and monitoring capabilities
should be employed to allow real-time, in-process
monitoring that prevents formation of hazardous
substances
12. Substances and forms of them used should be
chosen to avoid potentially harmful releases, fires,
and explosions
1.11. Some Things to Know About
Chemistry Before You Even Start
• Fewer than 100 naturally occurring elements, about 30
made by humans
• All elements composed of chemically identical atoms
• Each atom of a particular element has the same number
of positively charged protons in its nucleus equal to the
atomic number of the element.
• Electrons are in motion around the nucleus; a neutral
atom has equal numbers of electrons and protons
• Each element has a chemical symbol (nitrogen, N,
sodium, Na, for Latin name natrium
• The average mass of all atoms of an element is its
atomic mass
1.12. Combining Atoms to Make
Molecules and Compounds
• Two or more uncharged atoms bonded together by
chemical bonds compose a molecule
• A covalent chemical bond is composed of two or more
shared electrons
H
H
The H atoms in
elemental hydrogen
H
H
are held together by
chemical bonds in
molecules
H2
That have the
chemical formula H2
CHEMICAL COMPOUNDS
• A chemical compound is a substance consisting of
atoms of two or more elements joined together by
chemical bonds
H
H
H
O
H
O
Hydrogen atoms and To form molecules in
oxygen atoms bond which 2 H atoms are
together
attached to 1 O atom
H2O
The chemical formula of
the resulting compound,
water is H2O
Ionic Bonds
• Ions are electrically charged atoms or groups of atoms
• Cations are positively charged ions and anions are
negatively charged ions
• An ionic compound consists of cations and anions held
together by their opposite charges—ionic bonds—in a
crystalline lattice.
-
Na
Cl
Na+
Cl -
The transfer of a negatively charged electron from a
neutral sodium atom to a neutral chlorine atom
produces positively charged Na+ cations and negatively
charged Cl- ions held together by ionic bonds in the
ionic compound sodium chloride
1.13. Chemical Reactions
• A chemical reaction occurs when chemical bonds are
broken and formed and atoms are exchanged to
produce chemically different species.
CH4 + 2O2

Reactants
2H2O + CO2
Products
Yields
Above is a chemical equation for the reaction of
methane with oxygen. It is balanced because it has the
same number of each kind of atom (1 C, 4H, 4O) among
both the reactants and products.
1.14. The Nature of Matter and
States of Matter
• Most matter consists of mixtures composed of two or
more chemically distinct substances
• A homogeneous mixture, such as air, consists of
substances mixed at the molecular level that cannot
be separated by mechanical means.
• A heterogeneous mixture is composed of two or more
substances that are visibly distinct and can be
separated by mechanical means.
• Mixtures are important in green chemistry; the
separation of components of wastes and byproducts
is often a significant expense in recycling
States of Matter
A solid has a definite
shape and volume
regardless of the
container into which
it is placed.
A quantity of liquid has
a definite volume, but
takes on the shape of
its container.
A quantity of gas has
the shape and volume
of the container it
occupies.