Anhydrous liquid ammonia has a boiling point of -33.35 C, which might suggest that it would be a difficult material to handle, particularly in light of the familiar noxious odor of the gas. However, owing to hydrogen bonding, liquid ammonia has a relatively high heat of vaporization (23.3 J/mol vs. 40.7 J/mol for H2O). Thus, if kept in an insulated vessel (e.g., a Dewar flask), its rate of vapo...

Selectivity rules in organic chemistry have been inferred largely from nonaqueous environments. In contrast, enzymes operate in water, and the chemical effect of the medium change remains only partially understood. Structural characterization of the "ladder" polyether marine natural products raised a puzzle that persisted for 20 years: Although the stereochemistry of adjacent tetrahydropyran (T...

Synthesis and characterization of a polymethine cyanine near-infrared (NIR) fluorophoric label for the derivatization and determination of fatty acids separated by capillary electrophoresis are described. The label contains an aromatic amine functionality, which is used to form a covalent linkage with the analyte. Various linking chemistries are explored, including direct amine–acid condensatio...

Stochastic models that account for a wide range of pore-scale e€ects are discussed in the context of two-phase, immiscible displacement problems in natural porous media. We focus on migration of dense, nonaqueous phase liquids (DNAPLs) through watersaturated geological materials. DNAPL movement is governed by buoyancy, capillary, and viscous forces, as well as by the details of the porous mediu...

BACKGROUND The use of biocatalysts has become an increasingly attractive alternative to traditional chemical methods, due to the high selectivity, mild reaction conditions and environmentally-friendly processes in nonaqueous catalysis of nucleosids. However, the extensive use of organic solvents may generally suffer from sever drawbacks such as volatileness and toxicity to the environment and l...

The catalytic activity of four lyophilized oxidative enzymes-horseradish peroxidase, soybean peroxidase, Caldariomyces fumago chloroperoxidase, and mushroom polyphenol oxidase-is much lower when directly suspended in organic solvents containing little water than when they are introduced into the same largely nonaqueous media by first dissolving them in water and then diluting with anhydrous sol...

A comparison of the use of aqueous and nonaqueous buffers in association with beta-CD for the chiral separation of (R)- and (S)-3,4-methylenedioxymethamphetamine and related compounds is described. The (R)- and (S)-isomers of 3,4-methylenedioxymethamphetamine (MDMA) and its major metabolite 3,4-methylenedioxyamphetamine (MDA) were prepared. Under aqueous and nonaqueous buffer conditions and bas...

Current trends in electrochemical studies of nonaqueous solutions are discussed with the emphasis on experimental approaches judged to be particularly promising for the future development of both fundamental and applied aspects of the field of solution chemistry. Topics include recent developments in the application of potentio— metric sensors to nonaqueous solutions, the potentialities of such...