Alcohols, synthesis, alkane oxidation

Applications of HT-type catalysts, prepared by the above methods, have been reported in recent years for basic catalysis (polymerization of alkene oxides, aldol condensation), steam reforming of methane or naphtha, CO hydrogenation as in methanol and higher-alcohol synthesis, conversion of syngas to alkanes and alkenes, hydrogenation of nitrobenzene, oxidation reactions, and as a support for Ziegler-Natta catalysts (Table 2). 

The rationale for specific goals of this proposal is that the first step in new catalytic processes can be the availability of novel catalytic materials. Our initial focus has been to synthesize and characterize a variety of OMS and OL materials and scout out reactions that can be catalyzed by such systems. Catalytic oxidations with OMS and OL materials provide outstanding selectivity to terminal olefins and alcohols from alkanes. We have chosen to pursue these specific oxidations due to their importance in chemical synthesis and detergent applications,and to explore the fundamental reasons that such systems are highly active and selective. At the same time we have tried to limit our proposed synthetic efforts to a few new target OMS systems based on past experience. 

Supported copper-based catalysts are active for a great variety of reactions and there have been many fundamental studies of their catalytic and solid state properties. Among them, the oxidation of hydrocarbons and CO (1), alkanes (2) and alcohols (3) dehydrogenation, hydrogenation of ketones (4), allyl alcohols and a- and 6-unsaturated aldehydes and ketones (5), alcohol amination (6), low temperature water gas shift (7). methanol synthesis (8), oxidative condensation of methanol (9), hydrolysis of acrylonitrile to acrylamide (10), and removal of NOx pollutants (11). 

Ionic liquids have been used for a wide variety of oxidations, ranging from the relatively straightforward oxidation of alcohols to ketones, to the more difficult oxidations of alkanes. For clean synthesis, the oxidizing agent should give rise to... 

The conversion of Ught hydrocarbons into value-added functionalized products, under mild conditions, is still a serious challenge, but tris(pyrazol-l-yl)methane complexes of V, Fe, Cu, and Re have already been successfully applied as catalysts or catalyst precursors for relevant alkane oxidation reactions, namely, peroxidative oxygenations (to give alcohols and ketones) and carboxylations (to produce carboxylic acids). All these types of alkane reactions are promising toward the eventual exploration of alkanes as unconventional starting materials for synthesis. 

Pd-based catalysts have been shown to catalyse many oxidation reactions, including hydroxylation of benzenes, oxidation of alkanes, oxidative coupling reactions, epox-idation of alkenes and oxidation of alcohols/aldehydes (see Table 22.2)P- DilTerent synthetic approaches have been used for the synthesis of active Pd-based catalysts. 

Raw Material and Energy Aspects to Pyridine Manufacture. The majority of pyridine and pyridine derivatives are based on raw materials like aldehydes or ketones. These are petroleum-derived starting materials and their manufacture entails cracking and distillation of alkanes and alkenes, and oxidation of alkanes, alkenes, or alcohols. Ammonia is usually the source of the nitrogen atom in pyridine compounds. Gas-phase synthesis of pyridines requires high temperatures (350—550°C) and is therefore somewhat energy intensive. 

Although the unsaturated nitrile oxides 124 can be prepared via the aldoxime route (see Scheme 8), the older procedure suffers from the disadvantage that a tenfold excess of allyl alcohol and two additional steps are required when compared to Scheme 15. Therefore, unsaturated nitro ether 123 that can be prepared by condensation of an aldehyde 120 and a nitro alkane followed by Michael addition of alcohol 122, was a useful precursor to nitrile oxide 124 [381. The nitrile oxide 124 spontaneously cyclized to ether 125. This procedure is particularly suitable for the synthesis of tetrahydrofurans (125a-h) and tetrahydropyrans (125i-k) possessing Ar substituents in 72-95% yield (Table 12). The seven-membered ether 1251 was obtained only in 30% yield on high dilution. The acetylenic nitro ether 126 underwent INOC reaction to provide the isoxazole 127. 

Over the past 25 years, biomimetic model systems have been extensively studied and a wide variety of interesting oxidation processes such as the epoxidation of olefins, the hydroxylation of aromatics and alkanes, the oxidation of alcohols to ketones, etc., have been accomplished some of these are also known in enantioselective versions with spectacular ee s. The vast majority of these transformations were obtained using monooxygen donors such as those mentioned above as primary oxidants. The complexity of the catalysts and the practical impossibility to use dioxygen as the terminal oxidant have so far prevented the use of such systems for large industrial applications, but some small applications in the synthesis of chiral intermediates for pharmaceuticals and agrochemicals, are finding their way to market. 

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