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.

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.

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.

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.

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.

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.

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.