WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2006. — 648 p.
Nuclear Magnetic Resonance Imaging in Chemical Engineering
Forward
The field of nuclear magnetic resonance imaging (NMRI) has seen extraordinary technical advances since the seminal demonstrations of the technique by Paul Lauterbur and Peter Mansfield in the early 1970s. Driven by industrial and academic scientists and engineers, the advances in radiofrequency, magnet and gradient capabilities have been nothing short of remarkable. Most of these efforts have focused on biomedical applications, small animal and human imaging. The commercial (i.e. , for profit) and research (i.e. , grant funding) opportunities are unusually rich in the biomedical arena. Importantly for the life sciences, the primary imaging substrate is liquid-state water, which affords long NMR coherence times (tens to hundreds of milliseconds) and high spin densities (approx. 100 molar equivalent protons). The advantages conferred upon the field of NMRI by the approx. 70% water content of living systems cannot be overstated. Were water molecules NMR silent, it is unlikely that NMRI would have undergone such explosive technological developments and today it might be little more than a curiosity,
pursued in a few academic and industrial laboratories. Of course, water molecules are not NMR silent and NMRI engineering has, indeed, advanced at a remarkable pace to provide extraordinary technical capabilities. These capabilities now enable studies of systems beyond those in the biomedical arena, systems that are, in many respects, far more technically challenging. This has led to the development of innovative and fascinating strategies and
tactics to deal with NMRI-unfriendly samples and conditions. Coherence times in the solid-state can be distressingly short, tens to hundreds of microseconds, stimulating the development of novel spatial encoding methods. Samples to be examined can be fairly large, perhaps the wing of an aircraft or a truck tire or a gasket for a rocket engine, requiring the development of single-sided or inside-out NMRI scanners. Conversely, samples can be particularly small, for example, the output of a capillary separation column or a micro-fluidics reaction mixture, motivating the development of ultra high sensitivity micro-coils that can operate at very high magnetic field strengths. For samples composed of porous materials – filters, ceramics, concrete, etc. – the focus of interest is often the void structure within, which has lead to the development of diffusion and susceptibility sensitive methods that employ NMR active fluids and gasses. Reaction engineering is commonly presented with heterogeneous samples undergoing complex flow
patterns, requiring the development of velocity and displacement-sensitive imaging strategies. Combustion and catalytic processes taking place at high temperatures have motivated the development of special NMRI probes for dynamic monitoring of samples under extreme conditions.
This monograph provides a snapshot of current state-of-the-art technology and applications by the leading practitioners of NMRI in the broadly defined field of chemical engineering. The Editors have chosen internationally respected laboratories to contribute to sections on Hardware and Methods, Porous Materials, Fluids and Flow, and Reactors and Reactions. The result is an excellent compilation for the NMRI student requiring an introduction to the field, the junior scientist looking for an NMRI solution to a chemical engineering problem, or the NMRI expert anxious to understand more fully what the competition is doing. Hopefully this volume will be viewed as a timely contribution to the field and will find a place on the bookshelves of NMR scientists and engineers interested in exploring the power of NMRI beyond its traditional applications.
Joseph J. H. Ackerman Summer 2005
Associate Editor of Journal of Magnetic Resonance and
Professor and Chair of the Chemistry Department,
Washington University in St. Louis
