Ten different processes (Methods A-J) were tested to prepare tertiary amines bearing bulky alkyl groups. In particular, S1 alkylation of secondary amines with the help of 1-adamantyl triflate (Method D) and reaction of N-chlorodialkylamines with organometallic reagents (Method H), but also attack of the latter reagents at iminium salts, which were generated in situ by N-alkylation of imines (Method J), led to trialkylamines with unprecedented steric congestion. These products showed a restriction of the rotation about the C-N bond. Consequently, equilibration of rotamers was slow on the NMR time scale resulting in distinguishable sets of NMR data at room temperature. Furthermore, tertiary amines with bulky alkyl substituents underwent Hofmann-like elimination when heating in toluene to form an olefin and a secondary amine. Since the tendency to take part in this decay reaction correlated with the degree of steric hindrance around the nitrogen atom, Hofmann elimination at ambient temperature, which made the isolation of the tertiary amine difficult, was observed in special cases.

Nanoparticles immobilized on protective polymer supports are highly attractive for various applications in industrial processes. However, nanoparticles tend to agglomerate during the preparation of the polymer supports because of often used harsh conditions and thus lose their specific functionalities, like the catalytic active surface. Here, we report a method that solves the agglomeration and loss of activity by a sacrificial intermediate polylactide (PLA)/gold nanoparticle (AuNP) composite material that was coated with poly(p-xylylene) (PPX) and the selective removal of the PLA resulting in PPX/PLA/AuNP composite mesotube nonwovens with nonagglomerated gold nanoparticles on the inner walls of the polymer tubules. The immobilized AuNP were characterized extensively by electron microscopy and smallangle X-ray scattering (SAXS). With this system, we introduce carriers for nonagglomerated nanoparticles for use in heterogeneous catalysis. The functionality of the composite mesotubes was probed by a model catalytic reaction and compared quantitatively to other nanoparticle-based catalytic systems. The reaction rates, turn over frequencies, Au leaching, permeation of reagents specifically into the tubules, and the reusability were quantified in detail. We report that, in the catalytic model reaction with a gold loading 350 times lower than that of the state-of-the-art composite tubes with agglomerated AuNPs, the composite tubes offer a reaction rate 5 times higher. This system was also validated to work with the catalytic reduction of acetophenone, which is an important industrial reaction for the styrene production. Thus, this system, which shows reusability, stability against common solvents, no agglomeration of AuNPs, and no catalyst leaching, marks major progress toward the translation of high-efficiency nanoparticle catalysis to industrial use and the potential of transfer of other nanoparticle applications like sensoring.

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Dry powders embedded with gold nanoparticles (AuNPs) are produced by spray‐drying technique from an aqueous AuNP dispersion in a poly(vinyl alcohol) (PVA) or poly(vinyl pyrrolidone) (PVP) matrix. The prepared powders consist of AuNPs stabilized in hollow capsules of PVA (PVA@AuNP) or PVP (PVP@AuNP) with an average diameter of several micrometers. The AuNP powders are dispersible in water and no agglomeration triggered by the spray drying process of AuNPs is observed. The PVA@AuNP powders are coextruded with polycaprolactone to demonstrate the industrial application of dry‐state AuNPs. With PVP@AuNP the incorporation of AuNP into other stabilizing polymers via ligand exchange method is facilitated. After each step, the active surface of the AuNPs was tested by catalytic studies.