Strukturbildung und molekulare Beweglichkeit im Wasser und in wäßrigen Lösungen

Abstract

Wasserstoffbriicke" wird zusatzlich eine zweite Art von Strukturelementen, ein dritter Zustand, vorgeschlagen : kleinere Molekelaggregate, die neben tetraedrischen vorwiegend nicht tetraedrische Wasserstoffbriicken enthalten und eine dichtere Packung a1s die Netzstrukturen zulassen. Diese Molekelaggregate -Dimere bis Hexameresind als die primiiren Zerfallsprodukte der Netzstrukturen anzusehen und ersetzen diese als Strukturelemente des Wassers mit steigender Temperatur und mit steigender Konzentration geloster Stoffe mehr und mehr. Dieses ,,kombinierte" Strukturmodell la& die Eigenschaften des Wassers und die verschiedenartigen Einfliisse geloster Stoffe ohne innere Widerspriiche verstehen. Einleitung

Properties and Structure of Aqueous Solutions of Hydroxypropyl‐beta‐Cyclodextrin

“…The increase of viscosity which is concentration dependent is caused by interactions between single molecules via hydrogen bonds. Hydrogen bonds have only a very short life time of about lO-"s [18] thus we must consider permanent changes of this structure. Addition of urea results in a decrease of the viscosity, depending on the amount of urea added.…”

Dyeing from Solvents

“…The other difference lies in the fact that water has a special structure (3,6), which results in what are termed hydrophobic interactions (7). These interactions govern many properties of aqueous dye-liquors and are hence capable of influencing conventional dyeing processes.…”

A Proton NMR Study of the Deuterium‐Protium Fractionation in Aqueous Solutions of Some Organic Ions

“…The flame used was a standard 26.7 hPa (20 Torr), flat pre-mixed C2H2/02 flame of 7.5 cm diameter as described previously [lo]. A C/O ratio of 1.12 and a cold gas velocity of 42 cm s-' were chosen, also according to earlier measurements [6,7].…”

“…A comparatively simple method to measure the mass distribution of charged particles in a mass range from about lo3 to 5 . lo4 u is the energy discrimination of charged particles from a supersonic nozzle beam [6,7]. To evaluate the mass distribution from the distribution of kinetic energy the velocity distribution of the ions must be known.…”