University of Nottingham, UK

A champion of environmentally friendly chemistry encourages attempts to identify reactions ripe to be turned ‘green’.

The aim of ‘green chemistry’ is to make the design, production and use of chemicals more sustainable. This means that, unusually for an academic discipline, industrial implementation is an inherent goal.

Research groups in this field, including mine, strive to reduce waste by identifying selective catalysts, alternative solvents or renewable feedstocks that could lead to new industrial processes.

But how do we choose which reactions to try to green? Some targets are obvious; the reactions are notoriously inefficient. However, many chemical manufacturers are understandably reticent about the shortcomings of their processes.

It was therefore particularly refreshing to find a paper that results from the collaboration of seven pharmaceutical companies and highlights key research areas for green chemists (D. J. C. Constable et al. Green Chem. 9, 411–420; 2007). The paper describes several classes of reaction that, if ‘greened’, would significantly lessen the pharmaceutical industry’s effect on the environment.

For example, the paper asks that researchers develop methods to carry out oxidations safely in non-chlorinated solvents (chlorinated solvents are non-flammable but toxic); or to find ways to tame the fearsome reactivity of fluorine so that fluorination occurs selectively.

Another clear message is that new strategies for using solvents could lead to substantial reductions in waste. Could reaction vessels be cleaned out at the end of a process without using organic solvents?

This paper is a great start, but I think the authors have been too conservative. They could have asked for more, such as catalysts that can trigger two or more reactions in sequence. We need really tough challenges to intrigue academic chemists and bring new blood to the task of greening chemistry.