GREEN CHEMISTRY AND THE TEN COMMANDMENTS OF SUSTAINABILITY

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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_at_missouri.edu
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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

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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

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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

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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 wasteup
the chimney or down the riveris best.
From American Chemical IndustryA History, W.
Haynes Van Nostrand Publishers, 1954
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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

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1.2. THE ENVIRONMENT AND THE FIVE ENVIRONMENTAL
SPHERES
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The Atmosphere

• Very thin, most within several kilometers of
  Earths surface
• Provides oxygen for animals and other organisms,
  carbon dioxide and nitrogen for plants
• Vital protective function
• Stratospheric ozone protects against harmful
  ultraviolet
• Stabilizes Earths temperature by re-absorbing
  outgoing heat as infrared radiation
• Conduit for fresh water by way of the hydrologic
  cycle

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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

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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

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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

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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

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Environmental Chemistry
Environmental chemistry is the study of the
sources, reactions, transport, and fates of
chemical species involving all environmental
spheres
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Aquatic Chemistry
Gas exchange with the atmosphere
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Atmospheric Chemistry
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Chemistry of the Geosphere and Soil
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Chemistry of the Biosphere and Toxicological
Chemistry
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Chemistry of the Anthrosphere within a Framework
of Industrial Ecology
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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

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Command and Control Approach Emphasizing
End-of-Pipe Treatment Measures
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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.
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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

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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

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Yield and Atom Economy (1)
Typical reaction with less than 100 yield and
with byproducts
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Yield and Atom Economy (2)
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1.7. Reduction of Risk Hazard and Exposure
Risk Fhazard ? 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

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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

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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

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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

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Twelve Principles of Green Chemistry (2)

• 7. Raw materials should be from renewable sources
• Derivatization for blocking groups protection and
  property modification should be avoided
• Catalytic reagents should be used when possible
  because of their specificity and minimum amounts
  required
• Chemical products should be designed so that at
  the end of their lifetime they readily break down
  to harmless products
• The best analytical and monitoring capabilities
  should be employed to allow real-time, in-process
  monitoring that prevents formation of hazardous
  substances
• Substances and forms of them used should be
  chosen to avoid potentially harmful releases,
  fires, and explosions

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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

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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

The H atoms in elemental hydrogen
are held together by chemical bonds in molecules
That have the chemical formula H2
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CHEMICAL COMPOUNDS

• A chemical compound is a substance consisting of
  atoms of two or more elements joined together by
  chemical bonds

Hydrogen atoms and oxygen atoms bond together
To form molecules in which 2 H atoms are attached
to 1 O atom
The chemical formula of the resulting compound,
water is H2O
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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 chargesionic
  bondsin a crystalline lattice.

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
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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 ? 2H2O CO2
Reactants
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.
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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

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States of Matter
A quantity of liquid has a definite volume, but
takes on the shape of its container.
A solid has a definite shape and volume
regardless of the container into which it is
placed.
A quantity of gas has the shape and volume of the
container it occupies.