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‘Faster, cheaper, cleaner’

by Angela Herring

Most organic syn­thesis processes, which give us every­thing from small mol­e­cule drugs to fossil fuel replace­ments, require large vol­umes of haz­ardous sol­vents, pro­duce toxic byprod­ucts, and are extremely costly both in time and money. “The goal is to make things faster, cheaper, cleaner,” said Graham Jones, pro­fessor and chair of Northeastern’s Depart­ment of Chem­istry and Chem­ical Biology, who is helping to push the field of chem­istry into greener pastures.

North­eastern is one of 20 uni­ver­si­ties in the country that have joined forces to commit to a greener way of doing and teaching chem­istry. The group will work on devel­oping best prac­tices in the field as well as cur­ricula for both chem­istry majors and non-​​majors alike. For a truly green chem­ical industry, we must edu­cate not just future chemists but also non-​​chemist con­sumers, policy makers, and citizens.

In his own research, Jones is already pushing the green enve­lope. His team is pio­neering a set of new syn­thetic pro­ce­dures using both microwave and so-​​called “lab-​​on-​​a-​​chip” tech­nolo­gies to min­i­mize the envi­ron­mental and finan­cial impact of pro­ducing imaging agents for can­cers and cen­tral ner­vous system dis­or­ders. “The trick,” he said, “is finding drugs with flu­o­rine in them.”

That’s because he can exchange the benign flu­o­rine with a radioac­tive iso­tope, making the drugs vis­ible in PET scan­ners. Since they are inher­ently designed to bind to spe­cific cancer or dam­aged cen­tral ner­vous system cells, they will spon­ta­neously localize around a tumor or area of CNS damage. But the real nov­elty in Jones’ imaging drugs isn’t what they do, but how they are made.

Instead of a lab bench cov­ered with beakers and test tubes, Jones’ team does its syn­theses in minia­ture microflu­idic devices the size of a credit card. Because of the micro­scopic vol­umes, the chem­istry is fun­da­men­tally dif­ferent than it is on the macro-​​scale. For instance, it requires a frac­tion of the volume of sol­vent nor­mally used in the same reac­tions and pro­duces con­sid­er­ably fewer byprod­ucts. Because there are fewer byprod­ucts, less post-​​processing is required to purify the desired compounds.

The lab-​​on-​​a-​​chip takes care of the “cheaper” and “cleaner” vari­ables in Jones’ green equa­tion, but what about faster? To achieve con­sid­er­ably greater reac­tion speeds, the researchers flow the reac­tion mix­ture out of the microflu­idic device and into a microwave reactor where it gets a rapid burst of energy. A reac­tion that nor­mally takes hours now takes min­utes or sec­onds, Jones explained. Addi­tion­ally, the lab-​​on-​​a-​​chip industry has begun to stack the devices into par­allel pro­cessing units, allowing for increased scale-​​up potential.

Jones’ approach reflects a growing move­ment toward green chem­istry, wherein research and industry prac­tices alike adopt methods that are good for the envi­ron­ment and also “keep green in the wallet,” he said.  Other approaches include using cat­a­lysts to speed up reac­tions and devel­oping strate­gies to reduce the number of steps, volume of sol­vent, and wasted reagents.

One day, Jones said, green chem­istry will no longer be a nov­elty but the norm.

Originally published in news@Northeastern on August 7, 2013

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