STATE SELECT synthesis/optimization

Charged interphases may also be exploited to create high local concentrations of electron acceptors which affect the rate of electron transfer reactions confined within these restricted reaction volumes and diminish considerably the efficiency of the corresponding back-transfer [24], These results have been primarily applied in photochemical conversion projects [22,25], but technically more interesting applications may be found in their use for the development of new specific analytical procedures (e.g., optical or photoelectrochemical probes). High local concentrations are also of considerable interest in the optimization of photochemical dimerization reactions [22], as the rate of bimolecular reactions between excited and ground state molecules confined in an extremely restricted reaction volume (microreactor) will be considerably enhanced. In addition, spatial gradients of polarity may lead to preferential structures of the solvated substrate and, hence, to the synthesis of specific isomers [24, 22, 26], Similar selectivities have been found when monomolecular photochemical or photoinduced reactions [2,3] are made via inclusion complexes [27,28]. 

Moreover, it was recently shown that the deliberate removal of phosphatases from the in vitro translation mixture by immunoprecipitation results in increased protein yields (Shen et al., 1998). As proposed earlier (Jermutus et al., 1998), the elimination of one of the many causes of fast ATP and GTP depletion extends the time of synthesis, and, as a consequence, the total amount of produced protein. It should be possible to similarly remove proteases and nucleases (see above). Together with new ATP regeneration systems to keep the biochemical energy level at a high steady state (Kim and Swartz, 1999), the optimization measures mentioned should increase the level of synthesis of most proteins, and this should directly improve in vitro selection. 

Another approach that addresses the reduction of size of the MINLP is the state space approach by Bagajewicz and Manousiouthakis (1992). The basic idea of this strategy is to partition the synthesis problem into two major subsystems, the distribution network and the state space operator. The objective in the former is to make the decisions related to the distribution of flows in the superstructure, while the objective in the latter is to perform the optimization for the decisions selected in the distribution network. At the level of the state space operator one can consider the process either in its detailed level or simply as a pinch-based targeting model. While this strategy has the advantage of reducing the size of the MINLP, it is unclear how to develop automated procedures based on this approach. 

Today it is recognized that all three approaches (heuristics-based selection, geometric representation, and optimization methods) are useful, and indeed required, for complex process synthesis strategies. This follows because different applications lend themselves to quite different representations. This volume addresses a variety of these synthesis strategies for process subsystems, but represents only a sampling of the state-of-the-art of process synthesis research. The five chapters in this volume address quite different process subsystems and application areas but still combine basic concepts related to a systematic approach. 

In order to synthesize gasoline effectively from carbon dioxide through one-pass reaction system, methanol synthesis catalyst was improved. Pd and Ga were added to Cu-Zn based catalyst to optimize the state of Cu during the reaction. As the result, the space-time yield (STY) of methanol from CO2 was 1,410 gd h at 270, 80 atm and SV=18,800 /h. In second stage reactor in which H-Ga or Al-silicate was packed, methanol was converted to gasoline. Maximum selectivity to gasoline fraction was 54.4 % and STY was 312 gl h at 320 C and 15 atm. 

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