Safety and Environmental Considerations - Fundamentals of Industrial Chemistry: Pharmaceuticals, Polymers, and Business - page 246

and do not persist in the environment; (11) Analytical methodologies need to
be further developed to allow for real-time, in-process monitoring and control
prior to the formation of hazardous substances; and (12) 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.
The mnemonic, “PRODUCTIVELY” has been used [13] for the
twelve rules. It stands for P (prevent wastes - principle 1); R (renewable
materials - principle 7); O (omit derivatization steps - principle 8); D
(degradable chemical products - principle 10); U (use safe synthetic
methods - principle 3); C (catalytic reagents - principle 9); T (temperature,
pressure ambient - principle 6); I (in-process monitoring - principle 11); V
(very few auxiliary substances - principle 5); E (E-factor, maximize feed in
product - principle 2); L (low toxicity of chemical products - principle 4);
and Y (yes it's safe - principle 12).
Many, maybe even all, of these principles also make good business sense.
Many of the principles have been employed prior to the concept of green
chemistry. For example, consider principle one, “It is better to prevent waste
than to treat or clean up waste after it has been created.” This is true from
a green chemistry perspective but it is also true from an economic perspec-
tive. It costs money to deal with waste. In the first place, you have purchased
raw materials which are not being converted into saleable goods. Second, the
waste has to be handled. It either has to be purified or money has to be paid
for the disposal. Consider a simple example of a company that removes river
water to be used in their process. After use, the waste water has to be dis-
posed. It cannot be returned to the river unless it is first purified and tested to
ensure that the water quality is demonstrated to be of sufficient cleanliness to
be returned to the river without environmental impact. The purification and
testing cost money. Equipment must be purchased to handle the waste water.
If the process water usage is reduced by 50%, then less money is needed for
equipment, handling, purification and testing.
Consider principle 11, “Analytical methodologies need to be further devel-
oped to allow for real-time, in-process monitoring and control prior to the
formation of hazardous substances.” In-process monitoring speeds the feed-
back loop and minimizes the time spent making out-of-specification material.
For example, if a process sample is removed for testing and after a four-hour
test, it is found that there is something wrong with the process, the manufac-
turer has been making out-of-spec material for four hours. An adjustment is
made and another sample sent for testing. If the sample is still out-of-spec,
inferior material has been made for another four hours. Without a fast feed-
back loop, as is achievable using in-process monitoring, inferior material is
produced for several hours. For a plant running at a rate of 40,000 pounds
per hour, this one experience can result in several hundred thousand pounds