Green Chemistry: Principles, Importance and Challenges

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Polluted river.

Chemistry is often associated with pollution. Image by Carol Stroker, NASA.

What is Green Chemistry, and what is it based on? Science is making chemical processes more sustainable by reducing the amount of compounds used and reducing and/or eliminating the amount of toxic substances we produce.

Researchers have made important progress in Green Chemistry in recent years. Despite this, however, there are many challenges that could prevent these principles from gaining acceptance at a wider level.

Chemistry: a Dirty Word?

Many people, when hearing the word “chemistry,” immediately think about something dirty and dangerous.

Many people also think that “chemical compounds” are toxic, pollute our atmosphere, our rivers and seas, and potentially could seriously harm our health, if not kill us or seriously damage the environment.

This idea is partly due to the fact that many chemicals are indeed hazardous and need appropriate management to avoid excessive exposure. Moreover, in the past, there was much less awareness and consideration about the long-term effects chemicals could have either on humans or on the environment.

This led to the excessive and unconsidered use of some toxic compounds, without proper safety measures; unfortunately this caused some major environmental disasters, a more polluted environment and, in some places, serious health issues.

Green Chemistry

Green Chemistry uses non-hazardous compounds. Photo by Nemo.

Green Chemistry

Scientists introduced Green Chemistry in the early 1990s to address and partly solve these issues.

According to the ACS Green Chemistry Institute, the U.S. EPA and other institutions, a commonly accepted definition of Green Chemistry is:

“the design, development and implementation of chemical products and processes that reduce or eliminate the use and generation of hazardous substances.”

This approach is opposite to the “pollute and clean” attitude previously used in chemistry and industry.

12 Principles of Green Chemistry

The creators based their Green Chemistry on 12 principles, which were first published in 1998. Decoded Science spoke about this with Dr. Robert Pullar, research assistant from Aveiro University (Portugal). He tells us,

“One the key points of Green Chemistry is the use of benign, less toxic chemicals; this implies the development of alternative synthesis methods which could use less toxic solvents and/or starting materials. Ideally, processes should be based on water, not organic solvents.

Green Chemistry, however, is not just about toxicity and hazards, but also about energy efficiency/saving, reduction of wastes, and uses of renewable and sustainable sources. Basically green chemistry is about minimizing the impact on the environment in any possible way. An innovative non-toxic catalyst, for instance, which could allow a reaction to take place in milder conditions, is a good example of Green Chemistry. The use of wastes to make chemical compounds or materials we need is another example.”

Cork tree section.

Some natural materials show good energy efficiency. Photo by Plantsurfer.

Learning from Mother Nature

According to Dr. Pullar, we can learn about green chemistry from nature itself.

“If we consider energy efficiency, Mother Nature has a lot to teach us. Indeed, some natural materials, for example rocks and minerals, wood such as cork, and naturally occurring polymers have the best energy efficiency, and surely we should use them and/or consider as a model. We can also use natural structures as templates to create new forms of material, such as the porous or fibrous structure of wood.”

The prevention of waste generation, and accidental spillages and leaks, are also crucial aspects of green chemistry.

Green Chemistry: Growing Interest

Since its introduction, Green Chemistry has attracted more and more interest. Considering scientific publications published, for instance, in 1991 less than 100 papers on this topic; in 2010, however, the publication number was higher than 600. Of these publications in 2010, the two countries producing the highest number were US and China, with 18.14 and 15.34 % shares, respectively.

“Both the Royal Society of Chemistry (UK) and the American Chemical Society have journals dedicated to this topic – Green Chemistry and ACS Sustainable Chemistry & Engineering. This clearly shows the interest of the scientific community.” Dr. Pullar said.

Barriers to the Chemistry Cleanup

Despite the progress made in recent years, however, there are still barriers which prevent a further diffusion and acceptance of Green Chemistry. Decoded Science talked about this with Dr. David Constable, director of the ACS Green Chemistry Institute. He explains,

“Like for any new technology innovation, there are always barriers and resistance to full acceptance.

In the case of Green Chemistry, it is sometimes difficult to find economically viable ‘safer’ alternatives to a certain product or process. In many cases, there is a lack of agreement of what is considered ‘safer.’”

On the business supply chain side, it takes always time to switch from something old to something new; issues such as new product re-design, for instance, can be difficult and long.

Surely education is the key to the future; it is essential to have chemists and chemical engineers who understand how to incorporate Green Sustainable Chemistry into their work.”     

The First Steps to the Future

It is still early days for Green and Sustainable Chemistry, and it has yet to gain general acceptance globally as a viable alternative to current practices which govern how scientists perform chemistry and chemical engineering in industry and academia. However, there is growing interest in these ideas, both from the scientific and industrial communities. Political, societal and economic pressures should increase its importance in the future, driven by consumer demand and environmental needs.

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