Development of Sustainable and Green Chemistry

Event Date: 

Monday, April 27, 2015 - 1:00pm

Event Location: 

  • ESB 1001

István T. Horváth, Biology and Chemistry, City University of Hong Kong

By providing the fundamental knowledge on how to supply enough energy, water, food, and chemicals to the increasing population without simultaneously compromising the long-term health of our planet, the application of the definitions of sustainability, green chemistry, and green engineering in the development of sustainable fluorous chemistry and the sustainable and green valorization of the exoskeletons of crustaceans will be demonstrated.

Fluorous biphasic systems were based on the attachment of fluorous ponytails to reagents and catalysts in appropriate size and numbers. The preferred size was in the range of C6-C12 perfluoroalkylchains to achieve high fluorous solubility and partition in two phase systems. Compounds with C6-C12 fluorous ponytails could form C6-C12 perfluoroalkyl acids in the environment, some of which are persistent, toxic, and have long half-lives in humans. The replacement of longer perfluoroalkyl-chains with shorter C1-4-perfluoroalkyl-groups was proposed to limit accumulation and ensure high fluorous solubility. We have used t-C4F9-, n-C4F9-, and n-C3F7-groups to synthesize new fluorous aromatics, heterocycles, ethers, and phosphines.

Valorization of biomass-based wastes is perhaps one of the oldest practices of sustainable development, but it has to be reinvented to achieve higher sustainability in the future. The exoskeletons of crustaceans (lobsters, shrimps, and crabs) are major components of seafood wastes and they offer a unique opportunity for their valorization by selective conversion to chemicals. The major constituents of the exoskeletons include CaCO3 (42–67 %), proteins (15–46 %), and chitin (17–24 %) depending on the age/location of the species. Chitin is a linear polymer of 2-(acetylamino)-2-deoxy-D-glucose and primarily found in the exoskeletons of crustaceans, insects, and cell walls of fungi. The annual global production of exoskeletons from crustacean harvest is estimated to be 1.44 million metric tons on a dry weight basis. The accumulation of the exoskeletons has also become a major concern for the seafood processing industry. Since the biodegradation of chitin is rather slow, the conversion of the exoskeletons into useful chemicals and/or materials is desirable. We have developed a sustainable process to convert the chitin-rich, non-edible food residues to levulinic, acetic, and formic acids and ammonia. It should be noted that the presence of hemicellulose and cellulose in the food wastes is not an issue, as all of these could be converted to levulinic acid with high atom economy. The facile and complete conversion of levulinic acid to gamma-valero-lactone was also achieved by using the Shvo-catalyst.

The major challenges of sustainable development will be also discussed including the production of renewable energy, biomass-based fuels and consumer products, and fresh water.

István T. Horváth is a Chair Professor of Chemistry and Head of the Department of Biology and Chemistry, City University of Hong Kong. He received his Diploma in Chemical Engineering (1977) and Ph.D. in Chemistry (1979), both at the University of Pannonia, Veszprém, Hungary. He was a Postdoctoral Research Associate at Yale University (1982 - 1984), a Scientific Co-worker at the Swiss Federal Institute of Technology (ETH), Zürich, Switzerland (1984 - 1987), and a Senior Staff Chemist at Exxon (now ExxonMobil) Corporate Research, Annandale, New Jersey (1987-1998). After spending 10 years at the Institute of Chemistry, Eötvös University, Budapest, Hungary as a Professor, he moved to City University of Hong Kong in May, 2009. He has published over 150 scientific papers, book chapters and patents. He was the Editor-in-Chief of the "Encyclopedia of Catalysis" (Wiley, 2002), Editor of “Fluorous Chemistry” (Springer, 2012), and a Co-Editor of Aqueous Organometallic Chemistry and Catalysis (Kluwer, 1995), Handbook of Fluorous Chemistry (Wiley-VCH, 2004), and Multiphase Homogeneous Catalysis (Wiley-VCH, 2005). The books on fluorous chemistry were based on the fluorous biphasic concept he invented in the early nineties. He was the Chairman of the COST Action D29 on Sustainable/Green Chemistry and Chemical Technology (2002-2007). He was awarded a D.Sc. in Chemistry by the Hungarian Academy of Sciences in 1998 and was a Széchenyi Professor Scholar (2000 - 2003). He received the 1st Fluorous Technology Award in 2005, the Senior Humboldt Research Award in 2006, and the Green Chemistry Lecture Award in 2008. He is a Honorary Member of the Academia Nazionale di Scienze Letter e Arti, Modena, Italy (2010) and Fellow of the Royal Society of Chemistry (2013) and the American Chemical Society (2014).