2 research outputs found
Template-Particle Stabilized Bicontinuous Emulsion Yielding Controlled Assembly of Hierarchical High-Flux Filtration Membranes
A novel solvent-evaporation-based
process that exploits template-particle
stabilized bicontinuous emulsions for the formation of previously
unreached membrane morphologies is reported in this article. Porous
membranes have a wide range of applications spanning from water filtration,
pharmaceutical purification, and battery separators to scaffolds for
tissue engineering. Different situations require different membrane
morphologies including various pore sizes and pore gradients. However,
most of the previously reported membrane preparation procedures are
restricted to specific morphologies and morphology alterations require
an extensive optimization process. The tertiary system presented in
this article, which consists of a polyÂ(ether sulfone)/dimethylacetamide
(PES/DMAc) solution, glycerol, and ZnO-nanoparticles, allows simple
and exact tuning of pore diameters ranging from sub-20 nm, up to 100
nm. At the same time, the pore size gradient is controlled from 0
up to 840%/μm yielding extreme asymmetry. In addition to structural
analysis, water flux rates of over 5600 L m<sup>–2</sup> h<sup>–1</sup> are measured for membranes retaining 45 nm silica
beads
Magnetic Superbasic Proton Sponges Are Readily Removed and Permit Direct Product Isolation
Workup in organic synthesis can be
very time-consuming, particularly
when using reagents with both a solubility similar to that of the
desired products and a tendency not to crystallize. In this respect,
reactions involving organic bases would strongly benefit from a tremendously
simplified separation process. Therefore, we synthesized a derivative
of the superbasic proton sponge 1,8-bisÂ(dimethylamino)Ânaphthalene
(DMAN) and covalently linked it to the strongest currently available
nanomagnets based on carbon-coated cobalt metal nanoparticles. The
immobilized magnetic superbase reagent was tested in Knoevenagel-
and Claisen–Schmidt-type condensations and showed conversions
of up to 99%. High yields of up to 97% isolated product could be obtained
by simple recrystallization without using column chromatography. Recycling
the catalyst was simple and fast with an insignificant decrease in
catalytic activity