Amidacetale, Darstellung und Verwendung

Abstract

By integration of energy distribution functions for the cathode fall of H2 glow discharges we may show: Space charge is almost constant within a large part of the dark space, therefore the field strength is a nearly linearly decreasing function of distance from cathode. Deviations from linearity are quantitatively discussed. Composition of space charge: The contribution of atomic ions to the space charge may range from 5 to 10%. and the contribution of electrons from 0,1 to 10%, increasing with growing voltage. Relative ion and neutral current densities at the cathode (ion current from the glow edge = 1) are decreasing with growing voltage. Molecular neutral current density equals 3 to 10 times molecular ion current density, in case of atomic particles the relation is from 1 to 5. Total current density is increasing from 2.0 · 10−4 A/cm2 torr2 at the voltage U0 = 0,19 kV to 3,7 A/cm2 torr2 at U0 = 10 kV; cathode field strength is increasing from 0,53 kV/cm torr to 97 kV/cm torr. The mean energy of neutrals is smaller than the mean ion energy by a factor of about 0.45…0.85, and the mean energy of molecules is smaller than the energy of atoms by a about 0.2…0.8. The dependence of the mean energies from voltage is discussed. The energy gain of electrons is growing from 15% of total dark space energy at 0.19 kV to 70% at 10 kV; the energy gain of neutrals is decreasing at the same time.

Esterification of Carboxylic Acids and Etherification of Phenols with Amide Acetals

“…Nowadays, however, the Bredereck aminal (Me 2 N) 2 CHOt-Bu, which on dissociation generates the amidinium cation Me 2 N + =CHNMe 2 and the tert-butoxy anion, has become the preferred reagent for condensations with weakly activated methyl or methylene groups. [23][24][25] The chemistry of amide acetals has been reviewed, for example, in 1969, 35 1977, 36 and 1979. 37…”