Volume 85, Issue 8

The 4th International IUPAC Conference on Green Chemistry (ICGC-4) was held in Foz do Iguaçu, Brazil, 25-29 August 2012, under the auspices of IUPAC and the Brazilian Chemical Society (SBQ), with the theme “Exchanging experiences towards a sustainable society taking care of natural resources in their socio-economic development”. It is important to understand the historical context of ICGC-4 as part of a series that started in 2006 in Dresden, Germany. As observed by Prof. Tundo, the Chair of the first ICGC, green chemistry is “innovative because it is not necessarily connected to profits, it involves fundamental aspects and does not aim automatically at an industrial process. There is a great need to create a new type of chemistry focused on a new production system and utilization of chemical derivatives, in order to prepare the younger generation to reach a greener future.” ICGC-2 occurred in 2008 aboard the ship “Alexander Radishev” travelling from Moscow to St. Petersburg, Russia, and was centered around a number of fundamental and applied topics on green chemistry. ICGC-3 was held in Ottawa, Canada, 2010, with the theme “The Road to Greener Industry”. Bringing together academia and industry to exchange ideas about green chemistry was the purpose of the meeting. ICGC-4 also included all areas and sectors of chemistry worldwide (academia, industry, government, and chemistry societies) and focused on broad topics such as benign synthesis/process, green chemistry for energy/production, chemicals from renewable resources, green engineering, education in green chemistry, and engineering and policy. It attracted around 600 participants from 4 continents, especially young researchers. The event included 10 plenary lectures and 15 invited talks conducted by the most prominent chemists from all over the world in this field, 4 short courses, 15 parallel sessions with 4 oral presentations each, 3 technical parallel sessions, 4 roundtables, 2 poster sessions, and a book release (Capes at Rio+20). The organizers of ICGC-4 would like to thank the great number of sponsors who generously supported the event and the members of all committees for their immense contributions. Special thanks are extended in particular to Profs. Pietro Tundo and Buxing Han for their outstanding efforts, as well as Profs. Patricia Vazquez, Liliana Mammino, Arlene Corrêa, Vitor Ferreira, and Fernando Galembeck, all of whom contributed to the remarkable success of ICGC-4 (for more details, see www.ufscar.br/icgc4). The nine papers in this issue of Pure and Applied Chemistry are mostly contributions from plenary speakers and represent some of the topics discussed in the event. The tradition and involvement with such a fundamental and innovative field will continue in 2014 with ICGC-5, which will be held in Durban, South Africa. Vânia G. Zuin Secretary General

The plastics enterprise depends on a small number of commodity polymers to perform in diverse applications, requiring additives to produce desired properties and performance. Toxic effects and environmental persistence of certain additive chemicals impact the sustainability of the industry. Green chemistry has been and will continue to be applied to find solutions to these issues. This review focuses on alternatives to phthalate plasticizers and halogenated flame retardants, two categories that together account for a significant portion of the global additives market and the global dispersion of endocrine-disrupting chemicals. Small-molecule alternatives that exist in various stages of research and commercialization will be discussed, with emphasis on the use of renewable resources. The rise of biorefineries and new bio-based monomers may help overcome existing economic barriers to adoption of alternatives. Increasing the molecular weight of additives or covalently linking them to polymer backbones are two promising strategies for reducing both mobility and toxicity that will also be discussed. Finally, the design of new polymers that show desirable properties without the use of additives will be considered. The substances put forward as “green” alternatives have yet to receive the same level of scrutiny as diethylhexyl phthalate (DEHP, also known as dioctyl phthalate) or polybrominated diphenyl ethers (PBDEs). Cooperation between chemists, engineers, and the environmental health community will be critical to ensure the safety and sustainability of new technologies.

The availability of chemically rich food supply chain waste (FSCW) gives it considerable potential as a resource for the manufacture of chemicals including materials and fuels. By applying clean chemical technologies to the extraction and conversion of molecules from FSCW, we can aim to produce genuinely green and sustainable products to help meet the legislative and consumer-oriented demands of a sustainable society. Low-temperature microwave (MW) processing is a particularly powerful technology to achieve this aim and is shown to be effective for several different high-volume, geographically diverse biomass types.

The development of efficient, inexpensive, and nontoxic catalysts for cycloaddition of CO 2 with epoxides to produce five-membered cyclic carbonates is a very interesting topic. In this work, cycloaddition of CO 2 with propylene oxide (PO) to produce propylene carbonate (PC) catalyzed by potassium halides (KCl, KBr, and KI) in the presence of cucurbit[6]uril (CB[6]) was studied at various conditions. It was discovered that the potassium halides and CB[6] had excellent synergetic effect in promoting the reaction, and the KI/CB[6] catalytic system was the most efficient among them. The decrease of the activity and selectivity of KI/CB[6] was negligible after the catalytic system was reused five times. Further study indicated that the KI/CB[6] catalytic system was also very active and selective for the cycloaddition of CO 2 with other epoxides, such as glycidyl phenyl ether, epichlorohydrin, and styrene oxide. The mechanism for the synergetic effect of KI and CB[6] was also discussed.

The philosophy of green chemistry has been very well received in Latin America’s research and development programs. In this review we describe the green chemistry contributions of Brazilian research groups over the last three years.

Nanotechnology and green chemistry can have much in common from the point of view of processes, considering the possibilities of improving efficiency and quality, achieving a better economy of atoms and energy, promoting catalysis under mild and sustainable conditions, and facilitating online monitoring of production lines and environment. Some of these aspects are dealt with in this paper, focusing on selected examples of application of functionalized nanoparticles and -materials in chemistry and industry.

Metalloporphyrins (MPs) are known to catalyze in vitro a broad range of cytochrome P 450 -mediated reactions occurring in vivo. Most of the biomimetic research using MPs in oxidative catalysis has been directed towards the oxidation of organic compounds presenting significant reactivity features in one functional group. Much less effort has been made to imitate the oxidation of more complex molecules, with a range of functionalities, such as drugs or other xenobiotics. By varying the structure of the porphyrin, the metal ion, the oxidant, and the reaction conditions, it is possible to modulate the regioselectivity of the oxidation reactions. Recently, and along with studies on the synthesis and reactivity of porphyrins, chlorins, and phthalocyanines, our group was able to develop an interesting line of research in the field of biomimetic oxidation of organic compounds using environmentally benign hydrogen peroxide as oxidant and Mn(III) or Fe(III) porphyrin complexes as catalysts. The more up to date results obtained in such work are reviewed here.

Modern organic chemistry requires easily obtainable chiral building blocks that show high chemical versatility for their application in the synthesis of enantiopure compounds. Biomass has been demonstrated to be a widely available raw material that represents the only abundant source of renewable organic carbon. Through the pyrolitic conversion of cellulose or cellulose-containing materials it is possible to produce levoglucosenone, a highly functionalized chiral structure. This compound has been innovatively used as a template for the synthesis of key intermediates of biologically active products and for the preparation of chiral auxiliaries, catalysts, and organocatalysts for their application in asymmetric synthesis.

Even with the high costs of environmental exposure controls, as well as the chance of control failures, options for industries wanting to implement sustainability through frameworks such as green chemistry are not yet cost-effective. We foresee a “green” industrial revolution through the use of transformative technologies that provide cost-effective and sustainable products which could lead to new business opportunities. Through example, we promote the use of natural and abundant biopolymers such as chitin, combined with the solvating power of ionic liquids (ILs), as a transformative technology to develop industries that are overall better and more cost-effective than current practices. The use of shellfish waste as a source of chitin for a variety of applications, including high-value medical applications, represents a total byproduct utilization concept with realistic implications in crustacean processing industries.

Sustainable synthetic activity involving alternate energy input and greener reaction medium under aqueous or solvent-free conditions is summarized. This includes the synthesis of heterocyclic compounds, coupling reactions, and a variety of reactions catalyzed by basic water or recyclable and reusable magnetic nanocatalysts in aqueous media using microwave (MW) irradiation. Micropine-structured catalysts and magnetic nanoferrites and their post-synthetic modification with ligands and other nanometals serve as sustainable nanocatalysts in benign media. The strategic approach attempts to fulfill most of the green chemistry principles in a comprehensive manner and aims to create sustainable functional chemicals that may find large-scale use with significant waste minimization.

This recommendation proposes a definition for the term “halogen bond”, which designates a specific subset of the inter- and intramolecular interactions involving a halogen atom in a molecular entity.

A set of terms, definitions, and recommendations is provided for use in the classification of coordination polymers, networks, and metal–organic frameworks (MOFs). A hierarchical terminology is recommended in which the most general term is coordination polymer. Coordination networks are a subset of coordination polymers and MOFs a further subset of coordination networks. One of the criteria an MOF needs to fulfill is that it contains potential voids, but no physical measurements of porosity or other properties are demanded per se. The use of topology and topology descriptors to enhance the description of crystal structures of MOFs and 3D-coordination polymers is furthermore strongly recommended.

The evolution that has taken place in medicinal chemistry practice as a result of major advances in genomics and molecular biology arising from the Human Genome Project has carried with it an extensive additional working vocabulary that has become both integrated and essential terminology for the medicinal chemist. Some of this augmented terminology has been adopted from the many related and interlocked scientific disciplines with which the modern medicinal chemist must be conversant, but many other terms have been introduced to define new concepts and ideas as they have arisen. In this supplementary Glossary, we have attempted to collate and define many of the additional terms that are now considered to be essential components of the medicinal chemist’s expanded repertoire.