Chemical origins

Gloria M. Lawler and co-workers. Chemical Origins and Markets, Flow Charts, and Tables, 5th ed.. Chemical Information Services, Menlo Park, Calif., 1977. 

G. M. Lawler, Ed, Chemical Origins Markets, S " ed.. Chemical Information Services, Stanford Research Institute, Menlow Park, CA, 1977. 

A brief summary of current and potential processes is given in Table 8.1. As shown in the table, most of the reactions are hydrolysis, hydrogenolysis, hydration, hydrogenation, oxidation, and isomerization reactions, where catalysis plays a key role. Particularly, the role of heterogeneous catalysts has increased in this connection in recent years therefore, this chapter concerns mostly the application of heterogeneous solid catalysts in the transformation of biomass. An extensive review of various chemicals originating from nature is provided by Maki-Arvela et al. [33]. 

The chemical origin of free radicals in coffee is attributed to the sugars or carbohydrates, rather than phenolic constituents100. 

Gonis, J., Hewitt, D. G., Troup, G., Hutton, D. R., Hunter, C. R., The chemical origin of free radicals in coffee and other beverages, Free Radical Res., 23(4), 393, 1995. (CA124 85240e)... 

In the following we shall briefly review some of the recent applications of computational quantum chemistry to zeolites, in particular, some studies on the quantum chemical origin of Loewenstein s aluminum avoidance rule, and on the role of counter ions in stabilizing various structural units in zeolite lattices. These calculations are often extremely time consuming, nevertheless, the scope of their application is continuously expanding. 

The first example of the deliberate separation of optically active molecules is appropriate as an example of physical separation in the clearest sense of the term. The molecules are referred to as optically active because polarized light interacts differently with right- and left-handed molecules. In the case of simple diastereomers the RR and SS forms are enantiomers while the RS and SR forms are not. The separation of the latter and former was first done under a microscope using crossed polarizers and the crystals which were seen were separated from those that caused little or no rotation of plane-polarized light by hand using tweezers. A truly physical separation of chemical species using a physical property of chemical origin ... 

The behavior of practically all luminescent materials is sensitive to various parameters of physical and chemical origin. The excited state lifetimes and average intensities of the fluorescence and/or phosphorescence of these materials are modulated, for example, by temperature, oxygen, pH, carbon dioxide, voltage, pressure, and ionic strength. Consequently, the luminescence of various materials could be used, in principle, to monitor parameters of interest in medicine, industry, research, and the environment. 

Kleinfeld M Acute pulmonary edema of chemical origin. Arch Environ Health 10 942-946, 1965... 

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