Lewis design

Coutant, R. W., P. J. Callahan, M. R. Kuhlman, and R. G. Lewis, Design and Performance of a High-Volume Compound Annular Denuder, Atmos. Environ., 23, 2205-2211 (1989). 

Lewis D W, Sankar G, Wyles J K, Thomas J M, Catlow C R A and Willock D J 1997 Synthesis of a small-pore microporous material using a computationally designed template Angew. Chem. Int. Ed. Engl. 36 2675-7... 

R.A. Lewis, S.D. Pickett, D.E. Qark. Computer-aided molecular diversity analysis and combinatorial library design, in Reviews in Computational Chemistry, Vol. 16, K.B. Opkowitz, D.B. Boyd (Eds.). Wiley-VCH, New York. 2000. pp. 8-51. 

D J, D W Lewis, C R A Catlow, G J Hutchings and J M Thomas 1997. Designing Templates for Synthesis of Microporous Solids Using De Novo Molecular Design Methods. Journal of Molecular alysis A Chemical 119 415-424. 

First of all, given the well recognised promoting effects of Lewis-acids and of aqueous solvents on Diels-Alder reactions, we wanted to know if these two effects could be combined. If this would be possible, dramatic improvements of rate and endo-exo selectivity were envisaged Studies on the Diels-Alder reaction of a dienophile, specifically designed for this purpose are described in Chapter 2. It is demonstrated that Lewis-acid catalysis in an aqueous medium is indeed feasible and, as anticipated, can result in impressive enhancements of both rate and endo-exo selectivity. However, the influences of the Lewis-acid catalyst and the aqueous medium are not fully additive. It seems as if water diminishes the catalytic potential of Lewis acids just as coordination of a Lewis acid diminishes the beneficial effects of water. Still, overall, the rate of the catalysed reaction... 

The HCFC-225 isomers designed to replace CFC-113 are manufactured by Lewis acid promoted addition of HCFC-21 to tetrafluoroethylene... 

Evaluation of Phase 2 Conceptual Designs and Implementation Assessment Resultingfrom the Energy Conversion Alternatives Study (ECAS), NASA TM X-73515, NASA Lewis Research Center, Cleveland, Ohio, Apt. 1977. 

The ammonolysis of phenol (61—65) is a commercial process in Japan. Aristech Chemical Corporation (formerly USS Chemical Division of USX Corporation) currently operates a plant at Ha verb ill, Ohio to convert phenol to aniline. The plant s design is based on Halcon s process (66). In this process, phenol is vapori2ed, mixed with fresh and recycled ammonia, and fed to a reactor that contains a proprietary Lewis acid catalyst. The gas leaving the reactor is fed to a distillation column to recover ammonia overhead for recycle. Aniline, water, phenol, and a small quantity of by-product dipbenylamines are recovered from the bottom of the column and sent to the drying column, where water is removed. 

For the air—water system, the Lewis relation shows that r = 1. Under these conditions, the two parenthetical terms on the right-hand side of equation 33 ate enthalpies, and equation 33 becomes the design equation for humidification operations ... 

R. M. Clark and B. W. Lykins, Jr., Granular Activated Carbon—Design, Operation, and Cost, Lewis PubHshers, Inc., Chelsea, Mich., 1989, pp. 295—338. 

AC Good, R Lewis. New methodology for profiling combinatorial libraries and screening sets Cleaning up the design process with HARPick. I Med Chem 40 3926-3936, 1997. 

Robust design creates performance characteristics that are very insensitive to variations in the manufacturing process, and other variations related to the environment and time (Lewis, 1996 Sanchez, 1993). 

Pitts, G. and Lewis, S. M. 1993 Design Modelling the Taguchi Way. Professional Engineering, April, 32-33. 

Many chiral metal complexes with Lewis acid properties have been developed and applied to the asymmetric Diels-Alder reaction. High enantioselectivity is, of course, one of the goals in the development of these catalysts. Enantioselectivity is not, however, the only factor important in their design. Other important considerations are ... 

Figure 6 shows the scans of virgin and modified PS synthesized by using various Lewis acids. The position of each transition is designated by arrows. These transitions, which are observed to occur above room tempera-... 

Lewis directed subterranean resei voir studies to improve the efficiency of extracting oil from the ground. He designed the first bubble tower to effect more precise and efficient fractionation operations and provided important assistance in developing one of the first continuous thermal cracking process. 

Step-growth polymerization processes must be carefully designed in order to avoid reaction conditions that promote deleterious side reactions that may result in the loss of monomer functionality or the volatilization of monomers. For example, initial transesterification between DMT and EG is conducted in the presence of Lewis acid catalysts at temperatures (200°C) that do not result in the premature volatilization of EG (neat EG boiling point 197°C). In addition, polyurethane formation requires the absence of protic impurities such as water to avoid the premature formation of carbamic acids followed by decarboxylation and formation of the reactive amine.50 Thus, reaction conditions must be carefully chosen to avoid undesirable consumption of the functional groups, and 1 1 stoichiometry must be maintained throughout the polymerization process. 

Some workers have attempted to base the design of humidifiers on the overall heat transfer coefficient between the liquid and gas phases. This treatment is not satisfactory since the quantities of heat transferred through the liquid and through the gas are not the same, as some of the heat is utilised in effecting evaporation at the interface. In fact, at the bottom of a tall tower, the transfer of heat in both the liquid and the gas phases may be towards the interface, as already indicated. A further objection to the use of overall coefficients is that the Lewis relation may be applied only to the heat and mass transfer coefficients in the gas phase. 

Yamamoto H., Yanagisawa A., Ishihara K., Salto S. Designer Lewis Adds for Selective Organic Synthesis Pure Appl. Chem. 1998 70 1507-1512 Keywords Lewis-acid reagents... 

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