TECHNOLOGY
FT-NMR spectrometer analyzes solid samples A Fourier transform nuclear mag netic resonance (FT-NMR) spec trometer specifically designed for solid samples has been introduced by Nicolet Instrument Corp., Madison, Wis. The company designed the NMR-computer system according to o p t i m u m conditions for solids anal ysis worked out by Monsanto chem ists Jacob Schaeffer and Edward O. Stejskal (C&EN, Oct. 16, 1978, page 22), and has taken a license from Monsanto. M o u n t i n g the sample-spinning rotor on a double bearing with air-jet propulsion allows instant, precise, reliable spinning, which means that samples can be inhomogeneous or consist of loose fragments. Thus, in vestigators can analyze such materi als as coal, oil shale, polymers, cata lysts, foods, and biological specimens in their natural state. Spinning solids at the magic angle of 54.7° from the magnetic field di
rection averages out spin vectors of nuclei. The rotor is made of boron nitride, which is magnetically in visible in proton and carbon-13 spectral regions. The spectrometer uses a 2.3-tesla superconducting magnet, which corresponds to a 100-MHz radiofrequency (rf) signal for protons and 25 MHz for carbon-13. Nicolet chose a superconducting magnet to save the 200,000 kWh of electricity and large volumes of cooling water that an electromagnet would use in a year. Monsanto experiments had indicated that a field lower than 2.3 teslas w o u l d give insufficient resolution, whereas a higher field would need excessively high sample-spinning speeds to get rid of side bands, as well as excessive rf power for dipolar decoupling and cross polarization. Dipolar d e c o u p l i n g irradiates protons with an rf signal to saturate and decouple them from carbon-13
nuclei for sharper carbon-13 peaks. Cross polarization irradiates both protons and carbon-13 nuclei with rf signals tuned to cause both kinds of nuclei to spin at the same rate. Achieving such resonance in the ro tating frame eases transfer of mag netization from fast-relaxing protons to the usually more slowly relaxing carbon-13 nuclei. This causes the carbon-13 nuclei to relax faster be tween analyzing pulses of rf, thus shortening times n e e d e d to collect spectral data. The Nicolet computer adjusts rf signals for cross polariza tion within 0.1 decibel for exact matching of nuclear rotation rates. The magnet is oriented horizon tally rather than vertically, so access to the sample chamber is easier. The opening to the sample chamber is six inches in diameter, further easing sample changes. The h o r i z o n t a l placing of the magnet means that the system will fit well into rooms with 8-foot ceilings. The weight of the entire system is 1100 lb, so no special floor support is needed. For now, Nicolet offers a single probe, doubly tuned for both protons and carbon-13. The company plans to develop probes for other nuclei. Π
Advanced materials center planned for Berkeley
Nicolet's FT-NMR horizontal magnet makes sample changes easier 36
February 14, 1983 C&EN
Plans to establish a National Center for Advanced Materials (NCAM) at Lawrence Berkeley Laboratory have been announced by David A. Shirley, director of LBL. If approved by Con gress, construction of the center will begin later this year, with completion scheduled for 1989. The total cost will be about $140 million. The Reagan Administration's fiscal 1984 budget requests $35 million for the first phase of the project. As seems inevitable nowadays, competition from Japan and Euro pean nations in high-technology areas is cited as a reason for NCAM. As an example, Shirley points out that "Japan has a very highly inte grated infrastructure of university/ industry cooperation which has been developed to focus on high-tech nology problems. This will be one
part of America's response to that challenge. "The goals of the project are to redirect the capabilities of this na tional laboratory to address a vital national need, to accelerate basic re search in an area that promises me dium-term impact on high-technol ogy American industries, and to fos ter closer ties between industrial and university researchers and their counterparts in the national labora tory," Shirley says. The centerpiece of NCAM will be the advanced light source (ALS), w h i c h is described by Shirley as the first of the next generation of syn chrotron radiation sources. ALS will produce synchrotron radiation about 10,000 times more brilliant than current synchrotron sources. The radiation will be produced in very
iairmouiït short pulses, allowing studies not now possible with synchrotron radiation. ALS will be able to accommodate 12 beam lines. Essentially, ALS will be a 1.3-GeV electron storage ring. Present synchrotron radiation sources produce radiation when the ring's bender magnets force a packet of electrons around a curve in the ring. By contrast, ALS will produce the radiation in the straight sections of the ring through the use of "wigglers" and "undulators." Wigglers set up a magnetic field that is structured to force the packets of electrons to wobble as they travel down the straight sections of the ring. Each wobble is a change in direction and so produces radiation, most of which is directed along the straight section of the ring. Undulators take advantage of positive interference to further increase the light's intensity. ALS will be able to hold up to 300 packets of electrons simultaneously, which means that the light pulses can be spaced as closely as one every
2 nanoseconds. Each packet is held bunched tightly together so that 30-picosecond pulses can be produced. NCAM will include three other major components, each of which will take advantage of ALS: • A surface science and catalysis laboratory will be devoted to understanding catalysis on solid surfaces and developing new catalysts. • An advanced materials synthesis laboratory will develop and characterize new kinds of polymers, metal alloys, ceramics, and electronic materials such as ultrahigh-purity silicon. • An advanced device concepts laboratory will apply the improved understanding of the atomic and molecular properties of materials to new devices. Until the new light source is constructed, researchers will use the Stanford Synchrotron Radiation Source for experiments. That facility is being upgraded as part of the NCAM project. D
Your Domestic Source of
PHOTOSENSITIVE COMPOUNDS N-l-CHlOMDC 1,2-Naphthaquinone(2)-dia2ido-5-sulfonyl chloride Q and custom derivatives
Τ S02R
R = CI, Br, - O - a - N - R
ffl€THVl ABC 2,6-di (p-Azidobenzal)-4-methylcyclohexanone Ο
CH 3
HARD€N€ft N0.3 4,4' -diazidostilbene-2-2 ' -disulfonic acid disodium salt N 3
^ C SQjNa
Analogs & Homologs of these compounds are available.
fairmoiant: CHEMICAL
CO., INC
,NJ 07105 (201)344 5790 Te
The "bible" of chemical technology in 25 volumes—Volumes 21-24 due in 1983 Excerpts from reviews of the Third Edition: ".. .the quality, accuracy, and selection of information is excellent..." —Journal of the American Chemical Society "Kirk-Othmer is universally regarded as a reference work par excellence. It stands supreme in the field of chemical technology..." —The Chemical Engineer Individual volumes: (to February (after March Subscription Price: (to February (after March
28, 1983). . . . $165 per volume 1, 1983) $180 per volume 28, 1983). . . . $150 per volume 1, 1983) $165 per volume
Send the coupon for a FREE PROSPECTUS CALL TOLL-FREE 24 hours a day
(800) 526-5368. In New Jersey, call collect (201) 797-7809.
WILEY-INTERSCIENCE a division of JOHN WILEY & SONS, Inc. 605 Third Avenue, New York, NY 10158
KIRK-OTHMER ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY - - - - - MAIL FOR FREE PROSPECTUS Wiley-lnterscience, Dept. 092 605 Third Avenue, New York, NY 10158
"®-
Please send me a FREE PROSPECTUS on the 3rd Edition of the Kirk-Othmer Encyclopedia of Chemical Technology D Please telephone me a t i L D I have questions about D individual volumes and/or D a subscription. Name Company/Institution Address City/State/Zip_ Prices subject to change without notice.
3-1004
February 14, 1983 C&EN 37
