In 2050, the planet will be populated by more than 9.2 billion inhabitants. This sharp demographic growth has a direct impact on chemistry. Chemistry must continually produce more from resources which are dwindling or becoming increasingly difficult to use. Moreover, our growing awareness of our impact on the planet, and in particular of global warming, requires us to adapt and even design new processes and technologies which are continually safer, more energy efficient, and more environmentally friendly. While chemistry is of course not the only culprit in the case of greenhouse gas emissions, industry in general contributes up to 15-20 % of them.
In order to tackle these great challenges facing our society, chemistry presently has two options:
optimise processes based on the use of fossil carbon and the recycling of the resulting molecules/materials or
introduce renewable carbon sources (biomass, waste, CO2) into chemical processes.
GREEN CHEMISTRY DEFINITION
Green chemistry can be defined as the development of a chemistry that is continually safer and more environmentally friendly, but one that also integrates the necessities of societal and economic competitiveness. Green chemistry is a complex equation which must be sufficient to ensure the competitiveness of our industry while taking into consideration the challenges of access to various resources (carbon, water, metals), the issues of access to energy, global warming, the growth in the population for whom chemistry must ensure a peaceful development, and the erosion of biodiversity.
GREEN CHEMISTRY OR NOT?
Simply conforming to one or more of the twelve principles of green chemistry is of course insufficient justification for being deemed green chemistry. It is important not to consider an isolated reaction but to evaluate the process in its entirety.
HOW DOES ONE DEFINE A SUSTAINABLE PRODUCT OR MATERIAL?
Defining the sustainability of a molecule or material requires considering a reaction in its entirety. Listed below are the ideal criteria to which eco-designed molecules and materials should conform.
Molecules and materials should preferably be of renewable or recycled origin. In the case of renewable carbon, chemistry must be careful to respect the food/non-food equilibrium. When using recycled raw materials as carbon, mineral, metal, and energy sources (notion of a circular economy), chemistry must also be sure to maintain the stability of the main commodity chains.
Molecules and materials must be non-toxic with regard to ecosystems and human health, as well as biodegradable or recyclable.
Molecules and materials must be synthesised by a process that is environmentally-friendly for the planet and safe for human beings
Molecules and materials must engender progress in their intended application. The molecules and materials targeted must therefore lead to a real scientific or technological breakthrough.
Molecules and materials must be accepted by consumers. This directly involves the question of education and the major programmes currently emerging on the international stage.
Molecules and materials must be marketed at competitive prices so the consumer can make a choice that is ecological and not economical.
Molecules and materials must feature a noble application and not harm the population.
It is necessary to add two precautionary measures to these main principles:
There will be no green chemistry projects if there are no funds to back them up (in terms of investment, process cost, etc.). The success of green chemistry therefore depends on two main driving forces: 1. the development of a chemistry that is continually safer and more environmentally-friendly, and 2. its economic profitability.
Green chemistry is a dynamic system in the sense that the viability of a chemical transformation is directly dependent on cost and access to energy. In the current context, it is indeed extremely difficult to predict the sustainability of a process and of a molecule or material.