What’s green chemistry ?

For sure this question is interesting.

A thing is sure: answers we can hear everywhere are quite different and many times are indefinite or even contradictory.

In this article I will explain you ( on the basis of an historical scientific publication ) how you will be able to recognize green chemistry, its daily products and which real principles are leading it.

As known, chemistry, as a discipline, is quite enchanting, with all its colored solutions, bechers, glass instruments, fumes, reactions, etc… that sometimes explode !

Our collective fantasy is crowded by many persons with a white smock and some test – tubesin their hands.

Let’s be sincere: who never played at the “ young chemist “ at least once in his life ?

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When we became adults the initial fascination has been overcome by a more prudent approach.

May be you haven’t got occasion to study chemistry as I, but you too are using daily an incredible number of chemical products, many times without realizing it.

When we are hearing about “ green chemistry ” a great debate happens, sometimes even confusing.

It happens for many reasons:

- first of all, adjective “ green “ is more and more trendy and overused

- secondly, many times “ green “ is confused with “ non dangerous “, “ ecologic “ or “ natural “.

Many times things are in coincidence, but most times things have to be analyzed in details.

Now I will reveal you, on the basis of a scientific publication, the 12 green chemistry principles, with which you will be able answering to the following great questions:

- can really be green the chemistry ?

- which way can we distinguish green chemistry from traditional one ?

I can introduce now to the 12 principles of Green Chemistry, directly from Oxford University :

1. Prevention

It’s better to prevent waste formation than treat or clean them after their formation

2. Atomic economy

Don’t be afraid ! Here we aren’t talking about missiles or atomic weapons, but just about atoms. As you remind from your first chemistry lessons, atom is the smallest part of an chemical element that keeps all chemical properties of the element itself.

In chemical reactions, everything is in transformation, but not always all materials we produce are useful, therefore a great part of them has to be drained or transformed again. On the contrary, in green chemistry it’s important keeping all starting materials in finished products.

3. Less dangerous synthetic methods

Whenever possible, all synthetic methods have to be planned in order to use and generate substances with the minimum of toxicity, for human and environmental health.

4. Planning safer chemical products

Chemical products have to be planned in order to achieve desired functions by minimizing toxicity.

5. Safer solvents and additives

When usage of additives and solvents is necessary ( ad es. diluents, acetone, etc.. ) those who have less toxicity during their usage should be selected.

6. Energy efficiency

Energy need of chemical preparations has to be optimized in order to avoid any energy waste. Synthetic processes should be run at atmospheric temperature and pressure.

7. Renewable resources usage

Every raw material should be renewable and sustainable, whenever technically and economically viable.

8. Reducing derivatives

Derivation processes that aren’t necessary ( for example, using blocking agents, or systems of protection and de-protection, etc..) have to be minimized, since these steps request additional reagents who are producing non desired waste.

9. Using selective reagents ( catalysis )

Catalytic reagents, that aren’t consumed during the process, are preferred to the stoichiometric ones, that are totally consumed during the process.

10. Degradability

Chemical products must be planned in such a way that, at the end of their function, they can undergo a total degradation, producing non toxic by-products, that cannot damage the environment.

11. On time pollution monitoring 

Analytical methods have to be improved and enhanced to allow the online processes monitoring and predict formation of hazardous substances.

12. Accident prevention for a safer chemistry

All chemical substances have to be selected and used with the target of minimizing accidents, included air releases, as toxic fume releases, explosions and fires.

If you are interested in reading the original article in English, here you have reference :

Anastas P.T. and Warner, J.C.

Green Chemistry : Theory and Practice

Oxford University Press, New York, 1988, pag 30

( Courtesy of Oxford University Press )

 

See also :

Paul T. Anastas, Mary M. Kirchhoff

Accounts of Chemical Research, 2002, 35 (9), 686-694

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