The transition-metal catalyzed telomerization of 1,3-dienes with different nucleophiles leads to the synthesis of numerous products, such as sugar ethers, substituted lactones, or terpene derivatives, which can be applied in the cosmetic and pharmaceutical industry as well as in polymers and flavors. The reaction can be controlled by the choice of the catalytic system, the feedstock, and the reaction conditions. Since telomerization was developed in 1967, there have been many efforts to utilize this reaction. Herein we give an overview of the versatility of telomerization based on examples from research and industry, particular emphasis is placed on catalyst and process development as well as mechanistic aspects.
Wandelbar wie ein Chamäleon: Die übergangsmetallkatalysierte Telomerisation von 1,3‐Dienen mit verschiedenen Nucleophilen führt zur zahlreichen Produkten, die sowohl in Kosmetika und Pharmaka als auch in Polymeren und Duftstoffen Anwendung finden. Der Aufsatz gibt einen Überblick über diese vielseitige Reaktion mit Bezug auf die aktuelle Forschung und industrielle Anwendungen.magnified imageDurch übergangsmetallkatalysierte Telomerisation von 1,3‐Dienen mit verschiedenen Nucleophilen lassen sich zahlreiche funktionalisierte Kohlenwasserstoffe synthetisieren, z. B. Zuckerether, substituierte Lactone oder Terpenderivate, die in Kosmetika und pharmazeutischen Produkten sowie in Polymeren und Aromastoffen Anwendung finden. Die Reaktion kann durch die Wahl des Katalysatorsystems, der Reaktanten und der Reaktionsbedingungen gesteuert werden. Seit der Entdeckung der Telomerisation im Jahr 1967 gab es viele Ansätze zur Nutzung der Reaktion. In diesem Aufsatz wird anhand von Beispielen aus Forschung und Industrie die Vielseitigkeit dieser Reaktion verdeutlicht, wobei besonders auf Katalysator‐ und Prozessentwicklungen sowie ausgewählte mechanistische Aspekte eingegangen wird.
The telomerisation with phenol is an efficient way to convert the well accessible 1,3-butadiene into products of higher value. This article describes the optimisation of this reaction both on a laboratory scale using a novel multiphase semi-batch mode and in a loop reactor as an alternative concept for a continuous operation mode. The optimised parameters are applied in a miniplant offering an interesting salt-free route to octadienylphenols.
Supramolecular nanocomposite materials have emerged as a leading interdisciplinary research area that exploits synergistic relationships at the nanoscale to enhance the properties (mechanical and chemical) of nextgeneration biopolymeric materials. Hydrogels synthesized from natural biopolymers have emerged because of their intrinsic properties such as noncytotoxicity and biodegradability as well as their well-defined threedimensional, noncovalent network that is ideal for modification and functionalization. Therefore, it is critical to develop a mechanistic understanding tailored to the nuances involved in the interactions of the biopolymer scaffold with the functional additives present in these complex matrixes. This work will discuss the strategic design of hydrogels placing emphasis on the selection of the biopolymer network and the critical role that the incorporation of additives such as biomimetic cross-linking agents (lactones/amino acids) and antimicrobial nanoparticles (NPs) has on the properties and responsiveness of the final nanocomposite. Results have shown that the hydrogen bonding capacity of the biomimetic additives and antimicrobial agents (i.e., AgNPs) impacts the packing density of the hydrogel network and therefore modulates the resultant swellability. Furthermore, the addition of Ag-coated TiO 2 NPs (Ag/TiO 2 NPs) and biomimetic additives provided antimicrobial activity along with enhanced closure rates of simulated wounds in adult human dermal fibroblasts.
Sand, aus dem ApHorizont einer Parabraunerde (U12) sowie eine Schwarzerde (U4) im Vakuurn imprligniert (Alremiiller, 1974). Weiteres hbenmaterial wurde nach vorheriger Acetonsattigung stufenweise rnit Polyesterharz unterschichtet (Altemiiller u. Vorbuch, 1987). Die Viskositlit des Polyesterharzes wird durch DYNASY-LAN MEMO-E deutlich emiedrigt; der kapillare Aufstieg des Harzes in der Probe ist, vermutlich durch die verbesser-Z. P'nzenerndhr. Boded.. 154.44344 (1991) OVCH Verlagsgesellschaft mbH, W-6940 Weinkim, 1991 0044-3263P1/0612-0443 S 3.50 + .25B
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