Dream reactions

Dream reactions can be performed using chemical micro process engineering, e.g., via direct routes from hazardous elements [18]. The direct fluorination starting from elemental fluorine was performed both on aromatics and aliphatics, avoiding the circuitous Anthraquinone process. While the direct fluorination needs hours in a laboratory bubble column, it is completed within seconds or even milliseconds when using a miniature bubble column. Conversions with the volatile and explosive diazomethane, commonly used for methylation, have been conducted safely as well with micro-reactors in a continuous mode. 

Direct oxidation of methane to methanol is an obvious dream reaction ... 

From the Dream Reaction to the Real Process the Implemented HPPO Process... 

The NOx abatement in Diesel and lean-bum Otto engine exhaust gases is of special interest. The direct decomposition of NO into N2 and O2 (Eq. 10-10) is a dream reaction for catalyst researchers ... 

Why oxygen activation The widespread interest in oxygen activation, as is evidenced by the more than 200 publications a year devoted to the subject, stems from the enormous commercial potential that exists for selective catalysts for the dream reactions shown below (reactions 4-6). 

The quest for selective catalysts for the dream reactions discussed at the beginning of this article continues unabated. There is still a great need for systems that create gas-phase conditions in the liquid phase. One approach is maybe to isolate redox metal ions, by isomorphous substitution, in the lattice of molecular sieves [67]. Such redox molecular sieves may be viewed as inorganic en mes containing an active site in which there is no room for solvent molecules in addition to the substrate, i.e. gas phase conditions in the liquid phase. 

More specifically, we have several dream reactions. Can they be realized in the near future (Scheme 12.1)7... 

The asymmetric addition of water or ammonia onto olefins is one of the dream-reactions on organic synthesis and represents one of the (largely unsolved) problems of catalysis. Enzymes called hydratases or ammonia lyases can catalyze this reaction. However, they only act on activated alkenes, such as a,p-unsaturated carboxylic acids, and their substrate tolerance is rather narrow and only allow minor structural variations of their natural substrate(s), which severely limits their application in organic synthesis. 

The direct oxidation of methane to methanol or formaldehyde has been a dream reaction for a long time [537]. Attempts include gas-phase reaction, catalytic reactions, and use of other oxidants than air. Selectivities may be high, but at a lower conversion per pass resulting in yields being inferior for industrial use. 

It is often considered a dream reaction with H2/CO ratios lower than two at low conversions, but industrial utilisation would imply expensive recycle of non-converted methane as also discussed for direct conversion of methane (refer to Section 1.1.2). Other studies which claim high yields at low temperatures may be misleading [105]. 

In conclusion, an innovative route to valsartan that comprises decarboxylative biaryl coupling afforded this antihypertensive dmg in approximately 40% overall yield, which compares favourably with aU other reported routes. This approach was the result of meticulous synthetic experimental work. Professor Goosen stated that at the beginning of the project, one of his collaborators had performed close to 2000 test runs for the model reaction... before he observed the desired product in more than trace quantities [42]. The route to the dream reaction was extensively explored by Goosen s group. Fine-tuning of many parameters in the Cu(II)-catalyzed decarboxylative biaryl synthesis was performed [38, 41] and the final results were impressive... 

Figure 1 Dream reactions in the context of CO2 functionalization and their thermodynamic feasibility. A dream reaction is an economically highly attractive transformation, which is currently unfeasible due to a major scientific and/or technological challenge.

Among the various catalytic reactions studied, those applicable to environmental catalysis (e.g., automobile exhaust gas cleaning catalyst) attract particular attention. Initially, it was reported that perovskite oxide consisting of Cu, Co, Mn, or Fe exhibited superior activity to NO direct decomposition at higher temperatures [16 18]. The direct NO decomposition reaction (2NO = N2 -b O2) is one of the dream reactions in the catalysis field. In this reaction, the ease of removal of surface oxygen as a product of... 

A so-called dream reaction of high synthetic value is the asymmetric addition of water to a nonactivated C—C double bond, for example, in a styrene substrate molecule. Whereas an efficient chemocatalyst for this reaction is still unlmown [43], a combination... 

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