Centre in Green Chemistry and Catalysis (CGCC)
The CGCC was created in 2009 through the financial support of FRQNT and is composed of researchers from 7 universities across Quebec. In addition to the Université de Montréal, there are McGill University, Université Laval, the Université de Sherbrooke, Concordia University, the Université du Québec à Montréal and Polytechnique Montréal.
The scientific program of CGCC aims to yield major conceptual scientific advances in areas in which Quebec has already demonstrated its international leadership. More specifically, its mandate is to:
- Bring together talented researchers for the development of new green chemistry
- Enhance the quality of training by providing students with first-class infrastructure, high-quality professional support and scientific interactions with those in complementary disciplines
- Enhance the sharing of the world-class infrastructure among centre members
- Make significant advances in green chemistry/catalysis areas
- Encourage the creation of spin-off companies
- Increase public awareness of the benefits of green chemistry
The CGCC is a multidisciplinary centre, consisting mainly of chemists, as well as professors from the Faculties of Management and of Law. It not only addresses the optimization and efficiency of chemical transformations, but also examines the economic, legal and engineering aspects related to the development of chemistry in better harmony with the environment.
What is green chemistry?
Green chemistry is the design of chemical products and processes to reduce or eliminate the use and generation of hazardous substances.
This definition becomes clearer when we consider the 12 basic principles of green chemistry laid out by Paul T. Anastas and John C. Warner in a book published in 1998: limiting pollution, saving atoms, less-toxic raw materials, etc.
Chemists, and more specifically synthetic chemists, have traditionally been concerned mainly with preparing a target molecule and obtaining optimal yield for each step in its production. Little attention was paid to the amount of waste that was generated or the energy required by the chemical reactions used. Synthesis gives rise to energy-consuming reaction sequences and tends to produce large amounts of waste that sometimes exceed the amount of the desired product obtained.
In green chemistry, one established approach consists of performing chemical transformations in a more efficient manner by replacing stoichiometric reagents with catalysts, using less energy and little or no solvent, and, for reactions where solvent use cannot be avoided, using less harmful solvents.
Green chemistry is not the same as environmental chemistry. Green chemistry prevents potential damage to the environment, while environmental chemistry observes and quantifies chemicals released into the environment.
... and how is catalysis connected with green chemistry?
Catalysis is one of the approaches used to make chemical reactions more efficient and less energy consuming. Compared to reactions using stoichiometric reagents, catalysis reduces the amount of waste generated. In fact, the catalytic approach to chemical reactions is a pillar of green chemistry, an approach that results in significant gains in terms of overall efficiency of chemical reactions.
The Centre’s research axes
Axis 1: Development of green solvents for synthesis
Solvents play an auxiliary role in the preparation of chemicals but they are responsible for the majority of waste generated. Their removal and elimination requires supplemental energy and additional waste may be released into the environment.
Consequently, evaluating alternatives to conventional solvents is one of the mandates of the CGCC. Ideally, a green solvent should be non-toxic, readily available and inexpensive but, above all, it should have additional attributes such as increasing chemical reactivity, improving chromatographic separations or facilitating catalyst recycling.
Consequently, researchers are evaluating the use of green solvents such as water, supercritical CO2and ionic liquids in reactions relevant to synthesis.
New applications of supercritical fluid chromatography (SFC) are also being considered in the context of enantiomer separation. The work will provide alternative methods with low environmental impact to convert raw materials into useful products or synthetic intermediates.
Axis 2: Invention of new homogenous catalytic reactions
Conventionally, attaining the highest yield and product selectivity have been the governing factors of chemical synthesis. Little consideration has been given to the use of multiple reagents in stoichiometric quantities or of chiral auxiliaries, which often are not incorporated into the target molecule and can result in significant byproducts and waste to be eliminated.
It is increasingly recognized that it is highly desirable that all atoms of the starting materials and of the reagents be included in the product. The concept, referred to as "atom-economy," is one of the basic principles of green chemistry and has altered the way many chemists design and plan their syntheses.
Catalysis plays a central role in attaining high atom-economy for reactions, since, in a well-conceived reaction, minute amounts of catalysis can convert a starting material into more complex products.
Axis 3: Development of readily recyclable heterogeneous catalytic reactions
Heterogeneous catalysts have significant green advantages over their homogeneous counterparts, given the more facile removal of the metal catalyst from the reaction mixture, helping to ensure that there is no contamination of the product by the metal.
CGCC researchers are exploring 2 types of heterogeneous systems:
- Homogeneous catalysts immobilized on solid supports
- High-surface area nanoparticle catalysts
Each can be used to immobilize a normally homogenous catalyst and provide scientists with tools for further enhancing both the green and economic profile of these reactions. Combining these 2 catalytic approaches fosters collaboration between members and takes advantage of the expertise in surface chemistry at the CGCC. Not only will novel heterogeneous catalyst systems be developed, but the mechanistic aspects of the processes will also be studied.
Heterogeneous catalysis is often believed to be too difficult to study in a fundamental way. However, in the present global context of pressing concerns related to sustainable development, the study of heterogeneous catalysis is undergoing an explosive renaissance. The CGCC is very well placed to take part in the worldwide effort in catalysis and to lead to breakthroughs in a number of green chemistry catalytic processes.
Axis 4: Development of biochemical synthetic methods by using nature's catalysts and enzymes
As an alternative to synthetic catalysts, Nature has created extraordinarily effective catalysts for biological and chemical transformations, which, in almost all cases, operate in a green solvent: water.
A major thrust of green chemistry involves the use of biological catalysts or mimics of biocatalysts in chemical syntheses and processes.
The desirable features of enzyme-catalyzed reactions for chemical synthesis include high substrate specificity, high regio-, stereo- and enantioselectivities, and mild reaction conditions in aqueous media.
Some groups are collaborating by using enzymes to catalyze the regio- and stereoselective hydroxylations of unactivated C-H bonds in water. These are key reactions in the synthesis of many chemicals and pharmaceuticals, but are usually difficult to achieve. Studying the mechanistic aspect of the enzymatic reactions is also part of the CGCC's program.
Axis 5: Tools for green molecular synthesis and applications
Traditional synthetic methods use multiple steps to create the levels of molecular complexity desired in products. From a green perspective, these methods have significant limitations. They:
- Rely on reagents that are not fully incorporated into products.
- Require repeated solvent use.
- Suffer from diminishing yield with increase in number of reaction steps.
- Require repeats of the sequence to generate variants of the products to tune properties.
An alternative approach would be to prepare products directly from readily available resources. CGCC researchers are developing new non-catalytic green transformations that comply as much as possible with the atom-economy principle. These efforts provide a set of transformations that are easy to perform (one step), create minimal waste, and offer access to molecular diversity for the synthesis of new polymers, drug scaffolds, and new materials, all in a green manner.
Axis 6: Catalytic transformation of biomass
The catalytic transformation of biomass into important feedstocks creates new opportunities for Quebec's forestry industry. This important area seeks to transform the existing petrochemical-based chemical industry into one based on renewable materials for nature using catalytic methods. The production of industrial chemicals from renewable materials, such as plants and algae, is still in its infancy, yet is potentially vast. CGCC focuses on developing new bio- and chemical catalytic systems to generate important new biofuels and other commodities. In order for the biofuels industry to compete with current petrochemical manufacturing, waste streams that are created during biomass refinement must be converted into value-added chemicals. New catalytic processes that convert current bio-refining "waste" into important commodity chemicals is thus investigated. This important axis has been recently added to CGCC's research activity profile.
Axis 7: Evaluation, commercialization and policy development
The creation of alternative methods and synthetic platforms to convert feedstock into useful products and/or synthetic building blocks via green methods must also undergo careful scrutiny.
While these may be very effective processes relative to traditional synthetic methods, whether they are indeed environmentally benign must be carefully examined. Ultimately, in each of these green chemistry studies, it is critical that we determine whether the processes and the new chemicals synthesized are truly green. The pollution potential of both the native form and degradation products/eco-metabolites of new products are under investigation.
Another notable feature of CGCC is the inclusion of management and policy experts as members. These researchers study how the processes by which public concerns are (or are not) generated, and how policy changes result when policy-makers and other stakeholders are faced with new environmental and public health risks.
The evolution of technology is also being considered, especially how the chemical and pharmaceutical industries adopt new synthetic methods or alternative products. The Centre, while addressing all steps leading to a chemistry more respectful of the environment, allows researchers to become involved in innovation beyond the strictly scientific aspects.
Infrastructure – Université de Montréal
The member institutions of the CGCC provide a wide array of analytical services to the entire scientific community in Quebec, with some of the most recent equipment available and unique, state-of-the-art techniques.
- Elemental Analysis Laboratory (C, H, N, S)
- X-ray Diffraction Laboratory
- Regional Centre for NMR Spectroscopy
- Regional Centre for Mass Spectrometry
- Materials Characterization Laboratory
- Laboratory for Chemical Synthesis (including flow synthesis)