In the old synthetic route, each step had a yield of 90% so that the final
product came to be 40% yield compared to the starting chemical. This
resulted in the increased production of by-products as waste. The drug was
produced annually (only in Great Britain) in 3.000 tones and we understand
that substantial amounts of chemicals were lost as waste. Energy also was
lost by the low efficiency of the reaction method. In the “greener’ method of
three steps the final yield is 77%, whereas the Raney nickel catalyst (Nickel,CO/Pt) can be recycled and reused. In the old synthetic route, the AlCl3 used
as a catalyst had to be thrown away as waste. The energy requirements of
the second method were much lower than the first.
The new synthetic route of Ibuprofen is a classic example of how
Green Chemistry ideas can influence to the better the industrial synthetic
methods, not only from the point of economic efficiency, but also from the
point of more effective science and technology methods.