Basic Concepts from Organic Chemistry

The fundamental information that environmental engineers and scientists need concerning

organic chemistry differs considerably from that which the organic chemist

requires. This difference is due to the fact that chemists are concerned principally with

the synthesis of compounds, whereas environmental engineers and scientists are concerned,

in the main, with how the organic compounds in liquid, solid, and gaseous

wastes can be destroyed and how they react in the environment. Another major difference

lies in the fact that the organic chemist is usually concerned with the product of

the reaction: the by-products of a reaction are of little interest to him or her. Since few

organic reactions give better than 85 percent yields, the amount of by-products and

unreacted raw materials that represent processing wastes is of considerable magnitude.

In addition, many raw materials contain impurities that do not enter the desired

reaction and, of course, add to the organic load in waste streams. A classical example

is formaldehyde, which normally contains about 5 percent of methanol unless special

precautions are taken in its manufacture. Unfortunately, organic chemists have presented

very little information on the nature of the by-products of reactions to aid environmental

engineers and scientists in solving industrial and hazardous waste problems.

Fortunately, this is changing because of the large liabilities that companies now

face from discharge of environmental pollutants. Awards are now being given for

“green chemistry,” that is, for changing the ways chemicals are produced in order to

reduce the environmental harm they or their production cause.

The environmental engineer and scientist, like the biochemist, must have a fundamental

knowledge of organic chemistry. It is not important for either to know a

multiplicity of ways of preparing a given organic compound and the yields to be expected

from each. Rather, the important consideration is how the compounds react

in the atmosphere, in the soil, in water, and in treatment reactors, especially when

serving as a source of energy for living organisms. It is from this viewpoint that organic

chemistry will be treated in this chapter, and considerations will be from the

viewpoint of classes rather than individual compounds.