NMR puzzle pieces: A teaching tool, Chameleon clothing, Bitsy biodiesel device

• NMR puzzle pieces: A teaching tool
• Chameleon clothing
• Bitsy biodiesel device

NMR puzzle pieces: A teaching tool

Interpreting Nuclear Magnetic Resonance spectroscopy is a proverbial puzzle, but now students can handle puzzlelike pieces. John McClusky, an associate professor of chemistry at Texas Lutheran University, thought "there had to be a better way to teach NMR interpretation." So he developed a tool to help students learn how to "build" molecules on the basis of peak integration, multiplicity, and chemical shift in proton spectra. He introduced the "hardware" (cardboard pieces) for NMR Mosaic last year and says about 20 schools use it. Now, a computer program is also available online.

Both systems work the same way: Pick a generic Mosaic piece (CH₃, CH₂, etc.) by looking at a peak's integration on the NMR spectrum. Add colored, "static-cling" tabs to indicate connectivity, which is derived from the peak's multiplicity, and the presence of functional groups, which is derived from the chemical shift.

After all of the peaks in the spectrum are analyzed, students look at the colors on the fragments and fit them together to form the molecule. Any mistakes made in peak interpretation or connectivity soon become obvious because the colors are mismatched. Students and professors alike praise the puzzle-piece pedagogy.

Chameleon clothing

Soon it may be possible to change your shirt without actually changing your shirt.

Gregory A. Sotzing, a chemist at the University of Connecticut, in Storrs, has developed threads of electrochromic polymer. The knittable, washable thread could be used to change colors or patterns to suit a person's mood, outfit, or surroundings and was reported in New Scientist magazine.

Thin metal wires are woven into fabric with the polymer threads and connected to a battery pack and microcontroller. Each polymer thread changes state at different voltages. Electrons in the chemical bonds can absorb light across a range of different wavelengths. Connect the controller to a camera, and the threads could make you match the wallpaper. Cut the juice, and the threads revert back to their original color.

Sotzing overcame the problems usually associated with making long, electrochromic strands by spinning nonelectrochromic polymer with added groups of carbon and sulfur. Once the threads are spun, adding an oxidant causes the groups to react with each other and cross-link the strands. Voilà—electrochromic color.

The chemist claims that these threads are the first long fibers that can change color. Currently, the threads change from orange to blue and red to blue, but Sotzing hopes to create some that change from red, blue, and green to white. No word yet on yellow and purple.

Bitsy biodiesel device

Could a new gadget help farmers turn some of their crops into homegrown fuel so they can operate agricultural equipment without relying on costly imported oil? Goran Jovanovic thinks so.

The chemical engineering professor at Oregon State University has developed a microreactor that can convert vegetable oil directly into biodiesel. Roughly the size of a credit card, the device pumps vegetable oil and alcohol through tiny parallel channels, each smaller than a human hair, to convert the oil into biodiesel almost instantly.

By comparison, more than a day is needed to produce biodiesel with current technology. A catalyst, such as NaOH, is dissolved in alcohol and then stirred into vegetable oil in large vats for about two hours. The mixture then has to sit for 12 to 24 hours while biodiesel slowly forms along with glycerin, a by-product. The glycerin is separated and can be used to make other products, such as soaps, but it still contains the chemical catalyst, which must be neutralized and removed with HCl, a long and costly process.

The microreactor, which is under development by the university and the Oregon Nanoscience & Microtechnologies Institute, eliminates the mixing, the standing time, and maybe even the need for a catalyst. The device is small, but it can be stacked in banks to increase production levels to the volume required for commercial use, Jovanovic says. "If we're successful with this, nobody will ever make biodiesel any other way."