Chemical reactivity, factors affecting

In contrast to topochemical reactions in the crystalline state where the crystalline structure and the distance between reacting chemical bonds are crucial the reactions in amorphous polymer solids are governed by the mobility and heterogeneity of reactive sites. Besides chemical reactivity, factors which affect the reactions in polymer solids are summarized in Table 1. 

All these methods demonstrate that the 2-positions of pyridine, pyrimidine, and other azines are the most electron deficient in the ground state. However, considerably greater chemical reactivity toward nucleophiles at the 4-position is often observed in syntheses and is supported by kinetic studies. Electron deficiency in the ground state is related to the ability to stabilize the pair of electrons donated by the nucleophile in the transition state. However, it is not so directly related that it can explain the relative reactivity at different ring-positions. Certain factors which appear to affect positional selectivity are discussed in Section II, B. 

The Chemical Inherent Safety Index Ici (Eq.4) contains chemical factors affecting the inherent safety of processes. These factors consist of chemical reactivity, flammability, explosiveness, toxicity and corrosiveness of chemical... 

Considering the relevance of aza-PAHs in the elucidation of the mechanism of chemical carcinogenesis, our goal was to apply DFT methods to achieve a better understanding of the structural and electronic factors affecting the reactivity of this type of compounds. In this chapter we summarize our recent and ongoing computational studies in this field. 

Whether or not chemical reactivity hazards are present is a function not only of each chemical s reactivity (by itself and in combination), but also of various extrinsic factors i.e., factors that are not intrinsic properties of the chemicals being handled. As the design for a facility progresses, decisions will be made regarding these factors that will affect the magnitude of the chemical reactivity hazards and the potential consequences if their control is lost. A partial list of extrinsic factors includes ... 

In this article, the authors have attempted to supply a reference to the majority of pertinent papers on gas-carbon reactions. Reasons for the large amount of apparently conflicting data on orders and activation energies for the reactions are advanced. A detailed quantitative discussion of the role which inherent chemical reactivity of the carbon and mass transport of the reactants and products can play in affecting the kinetics of gas-carbon reactions is presented. The possibilities of using bulk-density and surface-area profile data on reacted carbons for better understanding of reaction mechanisms is discussed. Finally, some factors, other than mass transport, affecting gas-carbon reactions are reviewed. 

Surface Groups. Another factor affecting sorption characteristics is the chemical nature of the adsorbing surfaces. Solid sorbent surfaces may contain hydroxyl or phenyl groups, acid or base groups, or even reactive groups such as olefins. Polarities also... 

Geochemistry of Mineral Surfaces and Factors Affecting Their Chemical Reactivity... 

We begin with a discussion of the most common minerals present in Earth s crust, soils, and troposphere, as well as some less common minerals that contain common environmental contaminants. Following this is (1) a discussion of the nature of environmentally important solid surfaces before and after reaction with aqueous solutions, including their charging behavior as a function of solution pH (2) the nature of the electrical double layer and how it is altered by changes in the type of solid present and the ionic strength and pH of the solution in contact with the solid and (3) dissolution, precipitation, and sorption processes relevant to environmental interfacial chemistry. We finish with a discussion of some of the factors affecting chemical reactivity at mineral/aqueous solution interfaces. 

Factors affecting the chemical reactivity of mineral surfaces... 

A variety of interrelated factors affect the chemical reactivity of mineral surfaces with respect to water and aqueous species, including (1) defect density, (2) cooperative effects among adsorbate molecules, (3) differences in intrinsic properties of different mineral surfaces, including different isoelectric points, (4) solution pH,... 

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