History, preparation, and uses

In addition to this work on charcoal- and silica-supported catalysts and on evaporated platinum films, a number of studies have been made on alumina-supported platinum catalysts (e.g., 111-114, 81,115) in which the aim has been the study of reactions at the platinum alone. In these cases, one cannot automatically dismiss the possibility of participation of the alumina support (i.e., of dual function behavior of the catalyst) because it is known that alumina may have acidic properties, particularly when retained halogen is present. In general terms, there is no immediate answer to this problem because the nature of this sort of catalyst wall be much dependent on the details of catalyst history, preparation, and use. However, there can be little doubt that in many experimental studies using plati-num/alumina, and in which the assumption has been made that the alumina support is inert, this assumption is essentially valid. For instance, one may note the inert alumina used by Davis and Venuto (111) and the justification provided by Gault et al. (116) for the inertness of the alumina used in a substantial body of previous work irrespective of whether the catalyst was... 

The next section under Elements is subtitled History, Occurrence and Uses. This includes a brief history of chemical discoveries and the origin of their names and symbols, natural occurrence, principal minerals, abundance in the earth s crust and in sea water and principal uses. Uses include commercial applications, preparative reactions, analytical applications and other laboratory reactions. More general information is provided in this section. 

Noel G. Coley, The Preparation and Uses of Artificial Mineral Waters, Ambix 31, 1984, 32-48 idem, Physicians, Chemists, and the Analysis of Mineral Waters, in The Medical History of Waters and Spas, ed. R. Porter (Wellcome Institute for the History of Medicine, 1990). 

For the greater part of the history of 1,2,4-triazoles only two derivatives were used extensively one in small quantities as an analytical reagent and the other on a large scale for agricultural purposes. The number of triazole derivatives in either of these categories has increased greatly but only a small fraction of approximately one thousand patents covering the preparation and use of triazoles can be treated here. 

In actual practice, the antimony electrode does not give highly accurate results. The previous history, preparation, and surface characteristics of each antimony billet used affect the response. Each electrode must be carefully calibrated over the pH range to be used and factors such as dissolved oxygen and the composition of the buffer solution affect response. Nevertheless, the ruggedness, simplicity, very low resistance, and low cost of the antimony electrode have made it useful, for example, in continuous industrial-process monitoring when high precision and accuracy is not required. 

Contents Origin and History World and US. Production Processing Coconuts Selection, Preparation, and Uses Nutritional Value of Coconuts... 

Properties of Concentrated Polymer Solutions History of Polymers Preparation and Uses of Oligomers Polymeric Membranes for Separation and Purification New Developments in Additives for Coatings and Polymers... 

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