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The extended hydrogen bond networks formed by alcohols are good indicators of their capacities to hold water. Results from molecular dynamics simulations on 24 linear alcohol isomers containing 6–12 carbon atoms show the effects of hydroxyl location on bulk hydrogenbonded structures. Calculated oxygen–oxygen radial distributions obtained from simulations were correlated to experimental liquid–liquid solvent extraction studies involving ternary water/ethanol/alcohol systems. It was found that hydroxyl group location determines the primary structure of the bulk alcohol’s hydrogen bond network and that an alcohol’s capacity for water correlates directly to the size of this network. 2006 Elsevier Ltd. All rights reserved.

Distribution coefficients and separation factors were determined for the partitioning of ethanol and water from aqueous mixtures into several vegetable oils and their fatty alcohol and fatty ester derivatives. Castor oil, ricinoleyl alcohol, and methyl ricinoleate all show higher ethanol distribution coefficients, and similar or reduced separation factors, relative to other oils and derivatives studied here or reported by others. Of particular interest, ricinoleyl alcohol has an ethanol distribution coefficient 50% higher than that of oleyl alcohol, a commonly studied solvent for ethanol extraction from fermentation broths.

Velocity modulation spectroscopy has been investigated in the terahertz region, employing pure rotational transitions of ArH + and rotation-tunneling transitions of H3O + to study the competition between pressure broadening and Doppler broadening on the lineshapes, neutral suppression, and modulation efficiency. Velocity modulation is demonstrated to be effective to frequencies as low as 60 cm � 1 , yielding S/N values for ArH + (770/1) that surpass published terahertz FM results by an order

Online analyzers enable manufacturers to operate modern polymerization processes as safely, reliably, and profitably as possible. The most critical application of this technology involves monitoring the reactor itself to determine the molecular weight and comonomer content of the polymer produced. Polymer process streams introduce unique challenges for online analyzers because the process chemistry, sample transport, and stream conditions are harsher, prone to fouling, and pose unique safety hazards. Spectroscopy lends itself very well to online analysis of polymers because the data it provides is information rich and can be deployed using fiber optics for remote sampling of gases, liquids, and solids. Additionally, it is relatively fast and reliable if well designed and installed properly. The combination of spectroscopy, fiber optics, and chemometrics gives manufacturers the ability to use modern spectrometers and statistical models to analyze and monitor diverse types of polymerization processes. Several examples are provided in this article, including application to polyethylene, polycarbonate, polyurethane, and polystyrene processes.