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Green chemistry

Just fifty years ago, chemical industry consisted of large, mysterious and secluded complexes which processed dangerous and toxic substances at high temperatures and pressures. Employees and the surrounding population could, in case of reactions gone wild, be hit by explosions and toxic clouds. Installations were dominated by large pipes and furnaces, and high stacks which had to dilute exhaust gases and prevent harmful concentrations of toxic gases in the close neighbourhood. Those factories produced chemical waste, which posed great difficulties at removal.

Nowadays, we still see pipes, furnaces and high stacks, but they tend to belong to the past. New green chemistry performs its functions at a lower temperature and at atmospheric pressure, increasingly in water as a solvent (as opposed to organic substances), producing less (and above all less toxic) waste which can be reused, requiring less energy and producing a lower footprint. The key to all these changes is highly improved catalysis, the technology which allows chemical reactions to progress with minimal exertion (temperature, pressure) and maximal yield. Catalysis was very important in the ‘old’ chemistry, too; a science which thrived in Europe. But in green chemistry, one branch of catalysis has expanded hugely: biocatalysis. And in biocatalysis, too, Europe excels. Biocatalysis employs processes from nature: from yeasts, fungi, bacteria, from enzymes generally speaking. Biocatalysis allows us to perform reactions in the factory, as precise as in nature. Combined with ‘old’ catalysis, this allows us to produce virtually any chemical from biobased resources.

Processing complexity
Nature supplies the resources for this new chemistry. Green chemical researchers try to produce complex end products from complex resources, while retaining as much complexity as possible along the way. Because of this, green chemistry’s principles are diametrically opposed to those of petrochemistry. For this starts from a breakdown of oil molecules to simple building blocks, which are then meticulously reassembled to complex substances. Breakdown of oil and to building blocks, and reassembling building blocks to complex molecules, take place under pretty extreme conditions, and precisely from this stem the negative aspects of the ‘old’ chemistry. New chemistry is mild, it operates at moderate temperatures and pressures, it is more precise, it starts from renewable resources, and is better for both the economy as nature because of all this combined. The new ‘green’ chemistry can handle building blocks from petrochemistry as well as a starting point for further chemical synthesis (e.g. biomethanol, and bioethanol for the production of building block bioethylene), and this will surely take place in the start-up phase of the biobased economy. But the aim is to process complexity, further up the ladder of chemical production. This we call ‘holistic chemistry’.

At times, scientists can take a clear view of the future development of their scientific branch. Chemistry now is in such a phase. Chemical researchers predict a spectacular development of their subject, leading to increasingly better imitation or even improvement of natural processes, causing much less harm to the environment. The biobased economy is simply the economy in which this green chemistry has come to full bloom. The development of such a biobased economy will lead to quite another society, because of different ways of handling waste, and closing of all production loops. Such a society we call a biobased society, into which we shall look later.

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