{"73855":{"#nid":"73855","#data":{"type":"news","title":"Switchable Solvents Provide Greener Processing","body":[{"value":"\u003Cp\u003EA new class of solvents whose key properties can be rapidly \u0022switched\u0022 by the introduction of a common gas could provide a more environmentally-friendly way of producing specialty chemicals for the pharmaceutical and other industries.\n\u003C\/p\u003E\n\u003Cp\u003EA research team from Queen\u0027s University in Canada and the Georgia Institute of Technology in the United States reported on the development of the \u0022switchable solvents\u0022 in the August 24th issue of the journal \u003Cem\u003ENature\u003C\/em\u003E. The first example of what could become a family of such solvents can be changed from a non-ionic liquid to an ionic liquid -- and back again -- with the alternate addition of nitrogen or carbon dioxide.\n\u003C\/p\u003E\n\u003Cp\u003EThe ability to rapidly change the key properties of a solvent could allow multiple steps of a chemical reaction to be carried out without the need for removing and replacing solvents. That could potentially reduce pollution, cut cost and speed chemical processing.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022This process could provide a potential tool for benign and economical processing in the manufacture of high-value specialty chemicals,\u0022 said Charles Liotta, Georgia Tech\u0027s vice provost for research and graduate studies, Regents professor of chemistry and a member of the team reporting in the journal. \u0022One possible use for these solvents would be for such applications as the manufacture of pharmaceuticals and pharmaceutical precursors, especially for asymmetric or chiral compounds.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EChemical processing often requires multiple reaction and separation steps, and the type of solvent required for each step may be different. The solvent is therefore usually removed and replaced after each step, contributing to total processing costs, said Charles Eckert, a professor in Georgia Tech\u0027s School of Chemical and Biomolecular Engineering and director of the Specialty Separations Center. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022When you have to add and remove solvents, it\u0027s both expensive and polluting,\u0022 he noted. \u0022With this new class of solvents, we would be able to do what are called \u0027one-pot syntheses\u0027 -- that is, to carry out several steps in the same container with the same materials without having to do separations in between.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe switchable solvent system provides a means of reducing the environmental impact from producing pharmaceuticals and other products that are essential to society today, noted Philip Jessop, the paper\u0027s lead author and Canada Research Chair in Green Chemistry at Queen\u0027s University.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We all want the products of the plastics and pharmaceutical industries, but we don\u0027t want the pollution,\u0022 Jessop noted. \u0022Our research is seeking ways to decrease the amount of solvent waste being generated by these companies.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe reaction begins with a one-to-one mixture of two non-ionic liquids: DBU (1,8-diazabicyclo-[5.4.0]-undec-7-ene) and 1-hexanol. When carbon dioxide is bubbled through the liquid mixture at one atmosphere of pressure, the liquid becomes ionic. The change can be readily reversed, with the ionic liquid converted back to its previous non-ionic state by bubbling nitrogen or argon through it.\n\u003C\/p\u003E\n\u003Cp\u003EThe change of properties takes place at room temperature, and can be accelerated by raising the temperature to about 50 degrees Celsius. The change takes place rapidly, as soon as enough of the gas is bubbled through, Eckert said.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022The carbon dioxide actually reacts with a nitrogen atom of the amidine, so the carbon dioxide here is not a solvent -- it\u0027s a reactant,\u0022 he explained. \u0022That provides a redistribution of charge that makes the combination ionic. When the nitrogen gas is bubbled through, the carbon dioxide is swept out because it is only weakly bound, so the solvent goes back to its original state.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe researchers reported that the non-ionic liquid (hexanol and DBU) formed under nitrogen is as nonpolar as chloroform, while the ionic liquid formed under carbon dioxide is as polar as propanoic acid. The researchers demonstrated the polarity changes by testing the solubility of the nonpolar compound decane in each liquid.\n\u003C\/p\u003E\n\u003Cp\u003EThe solvent tested by researchers from Queen\u0027s and Georgia Tech is a \u0022proof of concept,\u0022 though practical applications aren\u0027t yet known. The work being done by the research team -- which also includes David Heldebrant and Xiowang Li, both from Queen\u0027s University -- is an example of how chemical design principles are facilitating the application of green chemistry.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We are designing molecules for a specific function,\u0022 Eckert explained. \u0022We decide what functions we want, then put atoms together in such a way that we can achieve that function. The collaboration of chemists and chemical engineers at different institutions is what makes it possible to look at both the molecular aspects and the applications.\u0022\n\u003C\/p\u003E\n\u003Cp\u003ESolvents known as ionic liquids are salts that are liquid at room temperature or near-room temperature. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022They tend to have a lot of organic character, and have been widely hailed as environmentally benign because they have no vapor pressure,\u0022 Eckert noted. \u0022They have applications where they are beneficial, and they have some unusual properties that we hope to use.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EEckert and Liotta are recipients of the 2004 Presidential Green Chemistry Challenge Awards, which recognized their collaboration in developing benign tunable solvents that couple reaction and separation processes.\n\u003C\/p\u003E\n\u003Cp\u003EGreen chemistry refers to the development of chemical processes and products that reduce or eliminate the use and generation of hazardous substances. Rather than focusing on the natural environment and pollutant chemicals in nature, this type of chemistry seeks to reduce and prevent pollution at its source.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We\u0027re concerned with pollution prevention rather than treatment,\u0022 said Jessop. \u0022That\u0027s a much more economic way to approach the problem.\u0022\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 100\u003Cbr \/\u003E\nAtlanta, Georgia 30308 USA \u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon, Georgia Tech (404-894-6986); E-mail: (\u003Ca href=\u0022mailto:john.toon@edi.gatech.edu\u0022\u003Ejohn.toon@edi.gatech.edu\u003C\/a\u003E); Fax: (404-894-4545) or Nancy Dorrance, Queen\u0027s University (613-533-2869); E-mail: (\u003Ca href=\u0022mailto:dorrance@post.queensu.ca\u0022\u003Edorrance@post.queensu.ca\u003C\/a\u003E) or Jane Sanders, Georgia Tech (404-894-2214); E-mail: (\u003Ca href=\u0022mailto:jane.sanders@edi.gatech.edu\u0022\u003Ejane.sanders@edi.gatech.edu\u003C\/a\u003E); Fax (404-894-4545).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"New class of solvents are more environmentally friendly for specialty processing"}],"field_summary":[{"value":"A new class of solvents whose key properties can be rapidly \u0022switched\u0022 by the introduction of a common gas could provide a more environmentally-friendly way of producing specialty chemicals for the pharmaceutical and other industries.","format":"limited_html"}],"field_summary_sentence":[{"value":"New solvents are more environmentally friendly"}],"uid":"27303","created_gmt":"2005-09-05 00:00:00","changed_gmt":"2016-10-08 03:03:38","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2005-09-05T00:00:00-04:00","iso_date":"2005-09-05T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"73856":{"id":"73856","type":"image","title":"Charles Liotta, Charles Eckert","body":null,"created":"1449178028","gmt_created":"2015-12-03 21:27:08","changed":"1475894681","gmt_changed":"2016-10-08 02:44:41"},"73857":{"id":"73857","type":"image","title":"Diagram of solvents","body":null,"created":"1449178028","gmt_created":"2015-12-03 21:27:08","changed":"1475894681","gmt_changed":"2016-10-08 02:44:41"}},"media_ids":["73856","73857"],"related_links":[{"url":"http:\/\/gtresearchnews.gatech.edu\/newsrelease\/greenchemistry.htm","title":"Green Chemistry Award"},{"url":"http:\/\/www.che.gatech.edu\/ssc\/","title":"Specialty Separations Center"},{"url":"http:\/\/www.chbe.gatech.edu\/faculty_staff\/faculty\/eckert.htm","title":"Charles Eckert"},{"url":"http:\/\/www.chemistry.gatech.edu\/faculty\/Liotta\/","title":"Charles Liotta"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[],"keywords":[],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}