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Syntheses of 1,2-, 1,3-, 1,4-, 1,8-, 2,4-, 3,4-, 4,8-, 1,2,4-, 1,2,8- and 1,3,4-functionalized dibenzofurans in few steps with good to excellent yields starting from dibenzofuran-1-ol or -4-ol are presented. These rapidly accessible bi- or tri-functionalized building blocks are of great interest for the synthesis of bioactive substances or functional material development. Furthermore, for intermediates containing both a bromine and a triflate moiety, a selective mono-substitution by means of Suzuki-Miyaura reaction (SMR) is described.

Im Rahmen von Sanierungskonzepten werden Verbrauchsprognosen zur Quantifizierung und Bewertung von Energieeinsparpotenzialen erstellt. Dabei ist zu beachten, dass sich das Verhaltnis von bilanziertem Energiebedarf und tatsachlichem Energieverbrauch vor und nach der Sanierung nicht linear verhalt. Wahrend der berechnete Warmebedarf vor der Sanierung haufig hoher ist als der gemessene Warmeverbrauch, ist er nach der Sanierung meist niedriger. Dieser vermeintliche Widerspruch wird mit den Begriffen „Prebound-Effekt” und „Rebound-Effekt” beschrieben. Prebound- und Rebound-Effekte konnen zu einer Uberschatzung der potenziellen Energieeinsparungen und zu einer Beeintrachtigung der Gesamtwirtschaftlichkeit von Sanierungsmasnahmen fuhren. Daher sollten sie in der Erarbeitung und Auswertung von Sanierungsstrategien berucksichtigt und einkalkuliert werden. Es wird ein Prognosemodell vorgestellt, das realistische Warme-Verbrauchsprognosen auf einer anpassbaren, empirischen Datengrundlage ermoglicht und sowohl fur Wohn- als auch fur Nichtwohngebaude anwendbar ist. Die Aggregation der Prognosen auf grose Gebaudebestande dient zur ganzheitlichen Optimierung gebaudeubergreifender Sanierungsstrategien. Am Beispiel des Campus Lichtwiese der TU Darmstadt wird das Prognosemodell exemplarisch angewendet und die Relevanz der Berucksichtigung von Prebound- und Rebound-Effekten verdeutlicht.

Oxidative thermal removal of the polymeric templates is not trivial for molybdenum oxides and hampers mesostructuring of this material. At ambient oxygen fugacity, MoVI is the thermodynamically stable oxidation state and sublimation of MoO3 leads to a quick loss of the mesostructure through Oswald ripening. Taking advantage of the Boudouard equilibrium allows to fix the oxygen fugacity at a level where non-volatile MoO2−x is stable while carbonaceous material may be oxidized by CO2. Mesostructured MoO2−x can be chemically converted into MoO3 or MoN under retention of the mesostructure.

The carbon content of mesostructured organic-inorganic hybrid material of a cylindrical block copolymer template of poly(2-vinylpyridine)-block-poly(allyl methacrylate) (P2VP-b-PAMA) and ammonium paramolybdate (APM) could be reduced by thermal depolymerization. By calcination in vacuo at 320 °C the PAMA core can be completely removed while the remaining P2VP brush preserves the mesostructure. The P2VP-APM composite can then be carburized in-situ to MoOxCy in a second pyrolysis step without any additional carbon source but P2VP. The molybdenum oxycarbide nanotubes obtained, form hierarchically porous non-woven structures, which were tested as catalyst in the decomposition of NH3. They proved to be catalytically active at temperatures above 450 °C. The activation energy was estimated from an Arrhenius Plot to be 127 kJ·mol–1.

The combination of phosphorus(V)-based Lewis acids with diaryl amines and diaryl silylamines promotes reversible activation of dihydrogen and can be further exploited in metal-free catalytic olefin hydrogenation. Combined experimental and density functional theory (DFT) studies suggest a frustrated Lewis pair type activation mechanism.

Cellulose is a renewable and widely available feedstock. It is a biopolymer that is typically found in wood, straw, grass, municipal solid waste, and crop residues. Its use as raw material for biofuel production opens up the possibility of sustainable biorefinery schemes that do not compete with food supply. Tapping into this feedstock for the production of biofuels and chemicals requires--as the first-step--its depolymerization or its hydrolysis into intermediates that are more susceptible to chemical and/or biological transformations. We have shown earlier that solid acids selectively catalyze the depolymerization of cellulose solubilized in 1-butyl-3-methylimidazolium chloride (BMIMCl) at 100 degrees C. Here, we address the factors responsible for the control of this reaction. Both cellulose and solid acid catalysts have distinct and important roles in the process. Describing the depolymerization of cellulose by the equivalent number of scissions occurring in the cellulosic chains allows a direct correlation between the product yields and the extent of the polymer breakdown. The effect of the acid strength on the depolymerization of cellulose is discussed in detail. Practical aspects of the reaction, concerning the homogeneous nature of the catalysis in spite of the use of a solid acid catalyst, are thoroughly addressed. The effect of impurities present in the imidazolium-based ionic liquids on the reaction performance, the suitability of different ionic liquids as solvents, and the recyclability of Amberlyst 15DRY and BMIMCl are also presented.

The hydrogenation of olefins is achieved using a combination of phoshorous(V)-based Lewis acids with diaryl amines for the activation of dihydrogen.

Hydrogenation of CO2 to formic acid (HCO2H) and methanol (MeOH) provides access to valuable products in a low-carbon economy. The development of effective processes for the production of pure HCO2H is still in progress. Hydrogenation of CO2 to MeOH is thermodynamically much more favorable (DG= 9.5 kJ/mole). However, homogeneous catalysts were kinetically not capable of reducing CO2 to MeOH until recently. In the MeOH process, the first organometallic catalyst being capable of the CO2 reduction to MeOH is immobilized in a stationary ionic liquid (IL) phase. The MeOH formed is continuously stripped from the IL phase by excess reaction gases.

The small size and conservative evolution of the chloroplast DNA make it an ideal molecule for tracing the evolutionary history of plant species. Most of the over 200 angiosperm chloroplast genomes examined are overwhelmingly similar in size, conformation, repeat structure, and gene content, and have the highly conserved gene order typified by spinach and tobacco. In fact, the chloroplast gene arrangement in spinach and tobacco appears to be the ancestral one among angiosperms (Palmer, 1985). Inversions and other mutations that change the relative order of genes are extremely rare. Where gene order differences are found they can often be accounted for by single large inversional switches. Such rearrangements, therefore, are potentially valuable characters for phylogenetic studies (Jansen and Palmer, 1987). Plants of the family Onagraceae represent a welldefined group of flowering plants that has been studied in biosystematic detail (Raven, 1988). Therefore, they appear an ideal group for the application of modem genetic and biochemical techniques such as the molecular analysis of chloroplast genomes as a way to elucidate their phylogeny. For example, examination of chloroplast DNA variation in the genus Clarkia proved useful in answering phylogenetic questions (Sytsma and Gottlieb, 1986). In the North American subsection Euoenothera of the genus Oenothera section Oenothera (see Stubbe and Raven, 1979) a gene rearrangement as compared to the spinach chloroplast DNA revealed a 45 kb inversion within the large single copy region (Herrmann et al., 1983). Although Epilobium and Fuchsia are closely related to Oenothera, the chloroplast DNA gene arrangement in Epilobium (Schmitz and Kowallik, 1986) and Fuchsia (Palmer, pers. comm.) resembles that in spinach and tobacco, i.e., they clearly lack the large inversion reported for Euoenothera. Therefore, this inversion is considered a derived character marking the subsection Euoenothera. To study further the phylogenetic distribution of the 45 kb Euoenothera inversion we have analyzed the chloroplast genomes of two South American Oenothera species belonging to the subsection Munzia (0. villaricae and 0. picensis). Restriction site maps of the chloroplast DNA of these species have been published previously (vom Stein and Hachtel, 1986). In addition, we evaluated representative species from other subsections of the genus Oenothera.