Factors affecting selection

The selection of safety measures for a particular application will depend upon a number of factors, including t,  

A common approach for reactors has been the provision of preventive measures, including control systems and safety trips, backed up by an emergency relief system. The addition of a relief,system is seen as having a number of advantages  

However, there are instances -when companies decide not to incorporate an 

In such cases, it may be acceptable to rely on preventive measures, of sufficient 

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Product distributions obtained on esterification of nucleosides and nucleotides under basic conditions throw further light on factors affecting selective reactivity. p-Toluenesulfonylation of adenosine 5 -monophosphate in aqueous alkali yielded exclusively (in 54-61% yield) the 2 -p-toluenesulfonate.107 Lack of reaction at HO-3 was attributed either to formation of a phosphoric p-toluenesulfonic anhydride, which sterically protected this hydroxyl group, or to the higher acidity of HO-2. It has been shown that the acidic site (with pKa 12.5) in adenosine is associated with the presence of both HO-2 and HO-3, as replacement of either of these by hydrogen, or of HO-2 by methoxyl, results in loss of this acidity.108 Inductive effects, or the sta-... 

Arnold, G. W. and Hill, J. L. (1972). Chemical factors affecting selection of food plants by ruminants. In Phytochemical Ecology, ed. J. B. Harborne, pp. 71-101. London Academic Press. 

Room temperature ionic liquids have potential as extractants in recovery of butyl alcohol from fermentation broth water solubility in ionic liquid and ionic liquid solubility in water are important factors affecting selectivity of butyl alcohol extraction from aqueous solutions (Fadeev and Meagher, 2001). 

VII. Factors Affecting Selectivity Roles of Crystal Structure, Nature of... 

Selectivity is determined by a competition between the rate of butadiene production and the rate of degradation of butene and other hydrocarbon intermediates. Various investigators have considered factors affecting selectivity (31,35-37). Generally speaking, along the selective oxidation pathway, the first abstraction of H to form rc-allyl can be viewed as a combination of an acid-base and a redox reaction ... 

These reactions illustrate a key point about radical reactions—a very important factor affecting selectivity is thb strength of the b onds being formed and broken. 

Chemically difficult (or currently impossible) hydroxylations on more complex terpenes can be accomplished by microbial methods, but Aere is as yet no clear understanding of the factors affecting selectivity. As is often the case, microorganisms suitable for a required transformation have been selected largely on precedent or on an empirical basis. In some cases respectable yields of one stereoisomer may result. 

Solvent effects in heterogeneous catalysis are examined in terms of physical or chemical modifications to control the chemo-, regio- and stereoselectivity of a reaction. The main factors affecting selectivity are reactant solubility, polarity, reactivity or acido-basicity of solvents and competitive chemisorption of products and solvents In the special case of molecular sieves, selectivity control of a reaction by competitive adsorption, diffusion or shape selectivity and confinement catalysis are also examined. 

Table 4-7. Factors Affecting Selection of Type of- Filter and Character of Pulps Handled ... 

Tan Y., Kilduff J.E. Factors affecting selectivity during dissolved organic matter removal by anion-exchange resins. Water Research 2007 41(18) 4211-4221. 

Scheme 5.5. Possible mechanism for electrochemical CO2 reduction catalyzed by CoPc-PVC. Reprinted from Figure 10 T. Abe, T. Yoshida, S. Tokita, F. Taguchi, H. Imaya and M. Kaneko, Factors affecting selective electrocatal5dic CO2 reduction with cobalt phthalocya-nine incorporated in a polyvinylpyridine membrane coated on a graphite electrode, Journal of Electroanalytical Chemistry 412 (1996) 125-132. Copyright 1996, with permission of Elsevier.

T. Okada, Factors Affecting Selectivity in Micelle Exclusion Chromatography of Inorganic Anions, J. Chromatogr., 538 341 (1991). 

The data listed in Tables 5.3-5.6 are simply observations concerning the effect of eluent concentration and resin exchange capacity on the retention factors of metal cations. A more fundamental approach is to examine the effect of physical and chemical variations in both the mobile and stationary phases on chromatographic behavior of ions. The factors affecting selectivity of ion chromatography have been reviewed in a recent publication [11]. 

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