WHEN IT COMES TO SOLVENTS, IONIC LIQUIDSare in a class by themselves. Compared to othersolvents in wide commercial use, they’re environ-mentally friendly — in a word, green. They’renonflammable and nonvolatile, releasing no harmfulvapors into the atmosphere. Amazingly versatile,their properties can be fine-tuned for applicationsin fields as varied as pharmaceuticals, fine chemicals,medical science, nanotechnology and environmen-tal remediation.

Ionic liquids are exceptionally potent as well.Research to date indicates that these solvents canbe customized with the chemical muscle to dissolvealmost any material, including metals, plastics andeven rock. And that’s not all of their virtues. Oneespecially useful type of ionic liquid can be madefrom a very renewable natural resource — pine trees.

“The potential of such agents is immense,”says Sanjay V. Malhotra, assistant professor in theDepartment of Chemistry and EnvironmentalScience at NJIT. “Properly formulated ionic liquidscould be a safe and effective way to dissolve andrecover dangerous chemicals that have been spilledon the ground. They might be used for mining, andfor refining petroleum. The list goes on and on.”

Given their qualities, it’s easy to understand whyionic liquids comprise one of the most intriguingareas of research for investigators like Malhotra,who has already participated in major grant-fundedstudies of these compounds. More work is on thehorizon with funding from sources that includethe National Institutes of Health and the U.S.Department of Energy.

Ionic liquids are organic salts that can be kept ina liquid state at room temperature, a breakthroughachieved only recently. Imidazolium and pyridiniumderivatives are typical examples. However, as a lab-oratory curiosity liquefied at higher temperature,the unique characteristics of these compoundshave been known for over 50 years. There is evenevidence that related compounds were used byBronze Age weavers to fix the dyes in their fabrics.

But in the twenty-first century, Malhotra explains,ionic liquids are a groundbreaking green alternativeto highly toxic solvents capable of causing signifi-cant environmental harm. Such solvents are basicconstituents of products as commonplace as paintremover, and they are critical in many complexindustrial processes. When employed as media forpromoting organic synthesis or catalytic reactions,ionic liquids offer other substantial advantages asalternatives to conventional solvents. They can besafely reused, along with making product recoveryeasier and allowing catalysts to be recycled.

Reflective of the current widespread interest inionic liquids, Malhotra points to the eight paperson the subject presented at an August 2004 meetingof the American Chemical Society (ACS) by mem-bers of his research team. A feature article on thepotential of ionic liquids for organic synthesis,which gives prominent mention to the work at NJIT,followed the Philadelphia ACS gathering in theNovember 8 issue of Chemical & Engineering News.

To promote investigation of the many applicationsfor ionic liquids, Malhotra and his colleagues havespearheaded the formation of the New York Regional

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PHOTO: BILL WITTKOP

IONIC LIQUIDS:THE GREEN

SUPER-SOLVENTSAUTHOR: DEAN L. MASKEVICHis editor of NJITMagazine.

Alliance for Ionic Liquid Studies, or NYRAILS.Malhotra says that this research consortium, whichincludes Rutgers University, The City University of New York, The State University of New York atBinghamton and Brookhaven National Laboratory,is the only organization of its kind in NorthAmerica dedicated to researching ionic liquids.

In addition to exploring the industrial utility ofionic liquids, Malhotra and his colleagues will belooking at how they can help to protect peopleagainst one of this century’s disturbing realities —chemical warfare. Reporting on the more than7,000 papers given in Philadelphia last August, theSeptember 13 issue of Chemical & EngineeringNews also singled out the discussion by Malhotraand PhD student Chengdong Zhang regarding theuse of ionic liquids as a superior assay medium totest for the presence of organophosphates. Thesecompounds, common in many insecticides andpesticides, are also a key ingredient of less benignchemical warfare agents.

But Malhotra is quick to emphasize how ionicliquids can open new paths to better health as wellaffording greater security against chemical attacks.This is the province of research focused on a specialclass of ionic liquids known as chiral ionic liquids.NJIT has one of the few labs in the world dedicatedto organic synthesis involving this type of ionicliquids.

In simple terms, chirality means that somecompounds can have either a “left-handed” or “right-handed” molecular structure, as discovered byLouis Pasteur. Such mirror-image forms can havevery different properties. What is a poison on theone hand, can be a medicine on the other. Chirality,Malhotra says, is the heart and soul of pharmaceu-tical development and production. Accordingly,because it’s possible to synthesize chiral forms ofionic liquids, they hold great promise for advancingbasic biomedical research as well as facilitating themanufacture of pharmaceuticals. ■

Department of Chemistry and EnvironmentalScience: www.njit.edu/chem

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Assistant professor Sanjay V. Malhotra and PhD student Chengdong Zhang were cited by Chemical & Engineering News for their paper on the potential ofionic liquids to detect chemical warfare agents.