Search results for "Reaction"
showing 10 items of 6134 documents
Initiierte autoxydation von isotaktischem und ataktischem polybuten-1 in lösung
1968
Isotaktisches und ataktisches Polybuten-1 (PB) wurden bei 70,6°C in brombenzolischer Losung mit Azoisobuttersauredinitril als Initiator mit Sauerstoff oxydiert. Die oxydierten Proben wurden isoliert, und der Gehalt an Hydroperoxidgruppen wurde mit Hilfe von Triphenylphosphin bestimint. Cyclische Peroxide, die bei oxydiertem isotaktischem Polybuten 1 moglich sind, konnen nicht mit Triphenylphosphin bestimmt werden, da sie zerfallen, bevor sie mit dem Phosphin reagieren. Dies wurde an niedermolekularen Modellverbindungen uberpruft. Unter den Reaktionsbedingungen war die kinetische Kettenlange so klein (1 bis 2), das deutliche Unterschiede der Oxydation von isotaktischem und ataktischem Polybu…
Surface Modification of Nanoparticles and Nanovesicles via Click-Chemistry
2019
Surface modification of nanocarriers offers the possibility of targeted drug delivery, which is of major interest in modern pharmaceutical science. Click-chemistry affords an easy and fast way to modify the surface with targeting structures under mild reaction conditions. Here we describe our current method for the post-preparational surface modification of multifunctional sterically stabilized (stealth) liposomes via copper-catalyzed azide-alkyne cycloaddition (CuAAC) and inverse electron demand Diels-Alder norbornene-tetrazine cycloaddition (IEDDA). We emphasize the use of these in a one-pot orthogonal reaction for deep investigation on stability and targeting of nanocarriers. As the prod…
Dry synthesis of B-MFI, MTN- and MTW-type materials
1997
Abstract B-MFI and MTN-type materials were synthesized via the fluoride route from dry powders in the complete absence of a solution phase. Amorphous precursors obtained by drying SiO 2 · Al 2 O 3 gels at 700°C were transformed into MTN-type material in the presence of dried NH 4 F and TMACl. Amorphous precursors obtained by drying SiO 2 gels at 700°C were transformed into B-MFI in the presence of dried NH 4 F, B 2 O 3 and TPABr. Water is formed as a reaction product. However, the water vapor pressure is appreciably below the water vapor saturation pressure under the given reaction conditions. In addition, syntheses using seed crystals were carried out successfully.
A new polyphosphate calcium material with morphogenetic activity
2015
Abstract Polyphosphate [polyP] has been proven to elicit morphogenetic activity on bone cells. By applying mild reaction conditions, a Ca-polyP material that displays a hardness of ≈1.3 GPa has been fabricated. The Ca-polyP granules are prone to hydrolytic degradation during in vitro incubation of the cells, suggesting that this property is associated with the observed bioactivity.
Shape-Dependence of Pd Nanocrystal Carburization during Acetylene Hydrogenation
2015
This interdisciplinary work combines the use of shape- and size-defined Pd nanocrystals (cubes of 10 and 18 nm, and octahedra of 37 nm) with in situ techniques and DFT calculations to unravel the dynamic phenomena with respect to Pd reconstruction taking place during acetylene hydrogenation. Notably, it was found that the reacting Pd surface evolved at a different pace depending on the shape of the Pd nanocrystals, due to their specific propensity to form carbides under reaction conditions. Indeed, Pd cubes (Pd(100)) reacted with acetylene to form a PdC0.13 phase at a rate roughly 6-fold higher than that of octahedra (Pd(111)), resulting in nanocrystals with different degrees of carburizati…
Thermal characterisation of Bio Based Building Materials
2006
This paper describes how the characterization of indigenous renewable biomass sources that are applicable for making bio-based building (BBB) materials is crucial as it can significantly affect the cost of production and the quality of material. Nowadays, in any specific area, wide ranges of biomass sources are usually available but only a few sources may be suitable for making BBB material. Therefore the suited sources should be determined. In this paper, the use of BBB materials is focused on Insulation Materials which are widely used in the buildings. Compared with currently used materials, these materials are bio-degradable. Insulation material with a good energy-adsorbing property and …
Synthesis of Morphinans through Anodic Aryl‐Aryl Coupling
2021
The morphinans are an important class of structurally fascinating and physiologically important natural products as exemplified by the famous opium alkaloids of the morphine family. Although this class of secondary metabolites from the juice of the opium poppy capsule was already used for medicinal purposes thousands of years ago, chemical modifications are still being applied to the core structure today in order to achieve the most specific effect on the various receptor subtypes possible with the fewest possible side effects. The unusual architecture of the morphinan core has also proven to be a highly challenging target for total synthesis. This review highlights electrosynthetic approac…
Inhibitoren der Korrosion (14). pH-Wert-Änderungen in Suspensionen von Eisen in 0, 2 m NaCl-Lösungen unter den Bedingungen der Sauerstoffkorrosion
1971
In einer geeigneten Apparatur werden in Suspensionen von Eisen bei unterschiedlichen Reaktionsbedingungen die pH-Werte laufend bestimmt. Es wurden folgende Ergebnisse erhalten: 1 In einer Suspension van 25 g Carbonyleisenpulver in 100 m reinem Wasser andert sich weder unter N2 nach unter O2 der PH-Wert. 2 Schuttelt man 25 g Carbonyleisenpulver unter 100ml 0,2 m NaCl-Losung, so steigt innerhalb von drei bis acht Minuten der PH-Wert van 6,60 auf 9,4-9,6 an. 3 Durch Bestimmung der Menge an gelostem Fe(OH)2 und Umrechnung in pH-Einheiten kann gezeigt werden, das der pH-Wert-Anstieg zuruckgeht. Corrosion inhibitors (14) pH variations in suspensions of iron in 0.2 m NaCl solutions under condition…
A Rapid Method for Amplification of Plastome DNA-Fragments from Spinacia oleracea by PCR
1993
Summary Polymerase Chain Reaction (PCR) was used as a very powerful technique to amplify DNA-fragments. Isolated chloroplasts and a crude suspension of small leaf pieces of Spinacia oleracea were osmotically shocked and subsequently heated. Aliquots of the resulting homogenate including the organelle DNA were directly added to basic reaction mixtures to carry out PCR without additional isolation- or purification steps. A 180 by DNA-fragment from the psbA-gene was amplified in both cases. In parallel, plasmid-DNA (pHT1) bearing the psbA-gene was subjected to PCR retaining unchanged reaction conditions. Identical DNA-fragments were obtained, as the following sequencing revealed. With the meth…
1,3-Oxazin-2-ones vs tetrahydrofurans by iodocyclisation of 2-alkoxycarbonylamino-3-alken-1-ols
2000
Abstract Iodocyclisation of primary homoallylic alcohols 2a – d , containing either a 2- t -butoxy- or a benzyloxycarbonylamino group, was studied, in order to establish the nucleophilic group involved in cyclofunctionalisation. In fact, the N - t -Boc derivative 2a gave the oxazinone 3 , exclusively, whereas starting from the N -Cbz derivative 2b a diastereomeric mixture of substituted tetrahydrofurans 4 and 5 resulted in ratios depending upon the reaction conditions. These results were rationalised by means of computational methods. On the contrary, migration of both the t -butyl or benzyl group to the hydroxy group was observed when both 2c and 2d underwent cyclisation to give the corres…