​Green Chemistry as an opportunity for Brazilian biomass

The need to develop new renewable raw materials for chemistry, replacing oil, has proven to be a strategic challenge for the 21st century.

In this context, the use of different types of plant biomass – starchy, lignocellulosic, oleaginous and saccharide – can be consolidated both as an alternative for the use of cheaper and less polluting raw materials, as well as a model for adding economic value to food chains. agro-industrial sectors, such as soybeans, sugar cane, corn, forests, among others. Such lines of action could, above all, contribute to the sustainability of a wide range of chemical products, especially organic ones, which are widely used in today's society.

Green chemistry emerged in the 1980s in countries such as England, the United States and Italy as a new philosophy in academia and industry to break old paradigms, such as the large generation of waste and the intensive use of petrochemicals, through a holistic vision. processes in laboratories and industries. This approach, described in 12 principles – seen later –, proposes to consider, among other aspects, the reduction of waste generation, atomic and energy savings, and the use of renewable raw materials.

In the case of the use of renewable raw materials, this is an extremely strategic issue for Brazil, as it is one of the main biomass producing countries and, consequently, one of the largest generators of agro-industrial waste that can serve as an abundant and cheap raw material. for chemical transformation processes.

In this way, the use of biomass through chemistry opens up a new business possibility and generation of wealth for the country, in addition to promoting a lower negative impact on the environment and the sustainability of production chains.

Chemical compounds are the products with the greatest potential for adding value to a given biomass chain, given the importance of the conventional chemical industry and fine chemicals in different sectors of the economy, highlighting compounds that can be used as building blocks , synthesis intermediates and polymers. This idea can be greatly explored by biorefineries. On the other hand, the need to develop technologies to obtain these products presents considerable bottlenecks to be overcome, both technical, scientific and market.

The 12 fundamental principles of green chemistry are as follows:

1. Prevention
It is better to prevent the formation of waste than to treat it after it is generated.

2. Atomic Economy
Synthetic methods must be designed to maximize the incorporation of all precursors into the final product.

3. Less Dangerous Syntheses
Whenever possible, synthetic methods should be designed to generate substances that have little or no toxicity to human health and the environment.

4. Designing Safe Chemicals
Chemicals should be designed for their desired function and to minimize their toxicity.

5. Safe Solvents and Auxiliaries
The use of auxiliary substances, such as solvents, separating agents, etc., should be unnecessary whenever possible and harmless when used.

6. Design for Energy Efficiency
The energy needs of chemical processes must be treated according to their environmental and economic impacts and must be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure.

7. Use of Renewable Raw Materials
A raw material should preferably be renewable whenever technically and economically feasible.

8. Reduce Derivatives
Unnecessary derivatizations, such as the use of blocking and protecting groups, and temporary physicochemical modifications, should be minimized or avoided, if possible, as such steps require additional reagents and can generate waste.

9. Catalysis
Catalysts, selective as possible, are superior to stoichiometric reagents.

10. Design for Degradation
Chemical products must be designed so that they can be degraded into harmless and non-persistent species in the environment.

11. Real-Time Analysis for Pollution Prevention
Analytical methodologies must be developed to allow real-time monitoring of processes in order to control the formation of dangerous substances.

12. Inherent Safe Chemistry for Accident Prevention
Substances and their form of use in a chemical process must be chosen to minimize the potential for chemical accidents, including releases, explosions and fires.

Such concepts, which also refer to clean production and green innovations, are already relatively widespread in industrial applications, particularly in countries with a highly developed chemical industry and which have strict control over the emission of polluting agents. They are based on the assumption that chemical processes with the potential to negatively impact the environment will be replaced by less polluting or non-polluting processes. Clean technology, pollutant reduction at source, environmental chemistry and green chemistry are names that have emerged and been coined over the last two decades to reflect the concern with chemical sustainability.

At Embrapa Agroenergia, efforts and investments have been made to use lignocellulosic biomass as a raw material for the renewable chemical industry, according to the seventh and ninth principles of green chemistry. Examples are projectsC5-AGGREGATE e Lignin Biorefinery. The first seeks to develop building block molecules and synthesis intermediates from the xylose constituent of hemicellulose from sugarcane bagasse; The second seeks to develop slow-release agrochemicals, additives for pharmacochemistry, among other products, from kraft lignin derived from wood pulping.

In the case of Brazil, the seventh principle – use of renewable raw materials – stands out as a great strategic opportunity for the country to enter, and even lead, segments related to different areas of green chemistry at a global level. An example of market segments that can be positively impacted by green chemistry and the use of biomass are:

- Polymers and materials for various applications;

- Commodities chemicals, such as monomers;

- Pharmaceuticals, cosmetics and hygiene products;

- Fine chemicals (agrochemicals, catalysts, etc.) and specialties;

- Fuels and energy.

In this way, it is possible to observe the wide range of opportunities for which Brazil can take the lead, both from a technical-scientific point of view and from a socio-economic point of view, generating foreign exchange and recognition for the country.