Clear Conversion Goals

Clearly, there is a need for techniques which provide access to enantiomerically pure compounds. There are a number of methods by which this goal can be achieved . One can start from naturally occurring enantiomerically pure compounds (the chiral pool). Alternatively, racemic mixtures can be separated via kinetic resolutions or via conversion into diastereomers which can be separated by crystallisation. Finally, enantiomerically pure compounds can be obtained through asymmetric synthesis. One possibility is the use of chiral auxiliaries derived from the chiral pool. The most elegant metliod, however, is enantioselective catalysis. In this method only a catalytic quantity of enantiomerically pure material suffices to convert achiral starting materials into, ideally, enantiomerically pure products. This approach has found application in a large number of organic... 

Saturated hydrocarbons are the main constituents of petroleum and natural gas. Mainly used as fuels for energy production they also provide a favorable, inexpensive feedstock for chemical industry [74]. Unfortunately, the inertness of alkanes renders their chemical conversion challenging with respect to selectivity. Clearly, the development of new and improved methods for the selective transformation of alkanes belongs to the central goals of catalysis. Iron-catalyzed processes might be a smart tool for such transformations (for reviews see [75-77]). 

In humans, at least, reward and punishment systems are clearly involved in conscious thought and behaviour. For example, anticipated rewards may be consciously deferred and relatively aversive activities carried out with the prospect of a future pleasurable goal. Conversely, instant pleasure may sometimes be seized despite knowledge of future punishment. Clearly, a degree of consciousness is required to choose the options. Almost every conscious activity carries some affective tone (Edelman Tononi, 2000 Greenheld, 2000) without this, there would be no motivation to do anything at all. This situation is seen in the anhedonia and apathy which sometimes accompanies schizophre-... 

However, since enzymatic hydrolysis is clearly hindered by steric effects, and since rapid conversion is usually desirable if the prodrug goal is improved aqueous solubility, deliberate increases in steric bulk should not be pursued (Anderson, 1985). 

Transmaterialisation is a more fundamental approach to the problem, which, with the goal of sustainable development, would ultimately switch consumption to only those resources that are renewable on a short timescale. Clearly petroleum, which takes millions of years to form, is not an example of such a sustainable resource. For the method to be truly effective, the wastes associated with the conversion and consumption of such resources must also be environmentally compatible on a short timescale. The use of polyolefin plastic bags for example, which have lifetimes in the environment of hundreds of years, is not consistent with this (no matter how they compare with alternative packaging materials at other stages in their lifecycle), nor is the use of some hazardous process auxiliaries which are likely to cause rapid environmental damage on release into the environment. 

Whereas the unit operation concept of chemical engineering asks for a clear separation of educt preparation. chemical reaction and product separation in different units, it is obvious that better conversion and selectivity might be achieved if educts arc added at the required amount and intermediates or products arc withdrawn from the place of reaction immediately Two general alternatives arc presently under discussion to achieve this goal, membrane methods and sorptive methods The basic difference is that membrane... 

For the nucleophilic substitution of aromatic CH bonds, electrochemistry has a clear advantage over chemical conversions. While at the anode, nucleophiles like OR, OCOR, Br, and CN can be introduced simply and in one step [60], chemically multistep procedures are necessary to achieve the same goal. 

The results of the actual assessment, then, met our goal of providing us with data that was both complex, qualitative, and rich (what we were most interested in), while also providing ways for us to make clear, quantitatively-based arguments when those are needed (what busy administrators are often most interested in). In the last year, for instance, we have been able to point to these data in conversations with the Assistant Vice President for Retention,... 

We are concerned with the synthetic approaches which could clearly identify the parameters controlling the spin-crossover characteristics (the sharpness of the thermal spin conversion, the temperature range width of the hysteresis as well as the value of the critical temperature r, 2)- Th ultimate goal is to tune the synthesis in order to provide compoimds with the proper value of those parameters for both theoretical understanding and exploration of applications. 

From the inspection of the gasoline pool of a conversion type refinery, it is clear that major contributions with respect to octane optimization, may be expected from the fluid catalytic cracker and the downstream upgrading of its products. The development of zeolites contributes very substantially to these goals, both by their introduction into FCC catalysts and their use in the upgrading of some of the side streams. 

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