Reaction, greenness factors, considered

Atom economy is strictly a theoretical number. The calculation considers only reagents from the balanced chemical reaction. The calculation does not include practical factors such as yield or excess reagents. A given reaction has the same atom economy whether its yield is 90% or 10%. Regardless, atom economy was the first accepted attempt at quantifying the greenness of a reaction. 

Electron-phonon interaction in a semiconductor is the main factor for relaxation of a transferred electron. There are two different relaxation processes that decrease the efficiency of light conversion in a solar system (1) relaxation of an electron from a semiconductor conduction band to a valence band and (2) a backward electron transfer reaction. The forward and backward electron transfer processes have been already included in the tunneling interaction, HSm-qd, described by Eq. (108). However, the effect of SM e-ph interaction is important for the correct description of electron transfer in the SM-QD solar cell system. In the previous section, we have gradually considered different types of interactions in the quantum dot and obtained the exact expression for the photocurrent (128) where the exact nonequilibrium QD Green s functions determined from Eq. (127) have been used. However, in... 

There are studies to suggest safer construction materials with the lowest possible risk on health for the indoor environment, mainly to decrease the effect of second factor (chemical contaminants from indoor sources) listed above [7, 8]. Most of these are natural , or in other words, they are green . However, one should also consider the fact that, all natural things are not safe. A number of natural materials can contain VOC and hence can pose hazards to health as well. Radon is an example, it is a natural material, which is radioactive and exists almost everjrwhere in the house. In addition, allergic reactions to the odours from cedar furniture, a natural material, are very common. The risk is always low if a certain agent remains in the building product that does not affect occupants through respiration and physical contact. 

Reacting lipophilic substrates with hydrophilic compounds, as in the case of most transesteriflcation reactions, is one of the major difficulties in lipase-catalyzed reactions. Several parameters need to be considered to overcome this immiscibility problem. One commonly proposed strategy is the use of a nonaqueous medium. In this chapter, the advantages of using nonaqueous media in biochemical synthesis reactions, over aqueous and solvent-free systems, are discussed. The use of hydrophobic solvents is also discussed, followed by a presentation of the alternatives that can overcome the limitations of solvents. The focus of this chapter is mainly on the use of supercritical fluids (SCFs) as a green alternative reaction medium. The chapter also discusses ionic liquids (ILs) as another alternative. These solvents and the factors affecting their physical properties and their effect on the activity and stability of lipase are also discussed. 

There are certain metrics used in Green Chemistry. One is associated with principle two Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. That is the metric of atom economy [14]. Atom economy is the mass of the product divided by the sum of the mass of all the reactants. Ideally this number is one and the closer to one the better. Atom economy does not take into account solvent or other reagents such as bases. Another metric is the Environmental factor or E-factor [15], The E-factor is the mass of the total waste divided by the mass of the product. Ideally the E-factor should be zero and the smaller the number, the better. However, some fine chemical or pharmaceutical syntheses have E-factors of about one hundred. Using micelles, the Lipshutz group reduced the E-factor of a Heck reaction from 137 to 7.5 and then even lower with recycle [16], Consider the following experimental procedure [17],... 

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