Is Green Chemistry the Future

The term green chemistry or sustainable chemistry came into fashion in the 1990s, with the first major books and journals in the field appearing toward the end of the decade. The 12 principles of green chemistry were adumbrated by Paul Anastas of the US Environmental Protection Agency in 1998.  

An important aspect of green chemistry involves atom economy. If we consider the oxidation of PhCH(OH)CHj to PhC(=0)CH3 using chromium trioxide, the atom efficiency, the proportion of the product that is actually something we want, is 42 % (Equations 25.4 and 25.5). If the oxidation could be done using molecular oxygen as the oxidant and a catalyst, then this rises to 86 % (Equations 25.6 and 25.7). In both cases, this is only a theoretical figure to get a more practical 

FIGURE 25.6 Green reactions with water as solvent. 

The key to solving this is to work out which atoms have been joined up. 

The synthesis of dieldrin starts with hexachlorocyclopentadiene, and the intermediate in the synthesis is another insecticide, aldrin. Devise a synthesis and give a mechanism for each step. 

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