GREEN CHEMISTRY


1.        What is Green Chemistry?

Green chemistry, also called sustainable chemistry, is a chemical philosophy encouraging the
design of products and processes that reduce or eliminate the use and generation of
hazardous substances. Whereas environmental chemistry is the chemistry of the natural
environment, and of pollutant chemicals in nature, green chemistry seeks to reduce and
prevent pollution at its source. In 1990 the Pollution Prevention Act was passed in the
United States. This act helped create a modus operandi for dealing with pollution in an
original and innovative way. It aims to avoid problems before they happen.

As a chemical philosophy, green chemistry applies to organic chemistry, inorganic chemistry,
biochemistry, analytical chemistry, and even physical chemistry. While green chemistry
seems to focus on industrial applications, it does apply to any chemistry choice. Click
chemistry is often cited as a style of chemical synthesis that is consistent with the goals of
green chemistry. The focus is on minimizing the hazard and maximizing the efficiency of any
chemical choice. It is distinct from environmental chemistry which focuses on chemical
phenomena in the environment.

2.        Twelve Principles of Green Chemistry.

a.        Prevention

It is better to prevent waste than to treat or clean up waste after it has been created.

b.        Atom Economy

Synthetic methods should be designed to maximize the incorporation of all materials used in
the process into the final product.

c.        Less Hazardous Chemical Syntheses

Wherever practicable, synthetic methods should be designed to use and generate substances
that possess little or no toxicity to human health and the environment.

d.        Designing Safer Chemicals

Chemical products should be designed to affect their desired function while minimizing their
toxicity.

e.        Safer Solvents and Auxiliaries

The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made
unnecessary wherever possible and innocuous when used.

f.        Design for Energy Efficiency

Energy requirements of chemical processes should be recognized for their environmental
and economic impacts and should be minimized. If possible, synthetic methods should be
conducted at ambient temperature and pressure.

g.        Use of Renewable Feedstocks

A raw material or feedstock should be renewable rather than depleting whenever technically
and economically practicable.

h.        Reduce Derivatives

Unnecessary derivatization (use of blocking groups, protection/ deprotection, temporary
modification of physical/chemical processes) should be minimized or avoided if possible,
because such steps require additional reagents and can generate waste.

i.        Catalysis

Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.

j.        Design for Degradation

Chemical products should be designed so that at the end of their function they break down
into innocuous degradation products and do not persist in the environment.

k.        Real-time analysis for Pollution Prevention

Analytical methodologies need to be further developed to allow for real-time, in-process
monitoring and control prior to the formation of hazardous substances.

l.        Inherently Safer Chemistry for Accident Prevention

Substances and the form of a substance used in a chemical process should be chosen to
minimize the potential for chemical accidents, including releases, explosions, and fires.