Functional groups, organic reactivity

Figure 13.1 The general structure of a silane coupling agent includes a functional group or reactive group at the end of an organic spacer This alkyl chain is attached to the central silicon atom, which also has up to three hydrolysable groups attached to it.

Traditionally, water is not a popular solvent for organic reactions. The limited solubility of many organic substrates and reagents as well as the fact that a variety of functional groups is reactive toward water have traditionally contributed to this lack of popularity of water as a reaction medium. Contrarily, the chemistry of all life processes occurs in aqueous media, and few people will doubt the high quality and efficiency of these transformations ... 

In conclusion, we have achieved a detailed picture of the activity and the form of interactions with polar and charged species of organic functional groups representing reactive sites of humic substances and of two important soil minerals, kaolinite and... 

Functional Groups The reactivity of organic compounds can be reliably predicted by the presence of functional groups, which are groups of atoms that are laigely responsible for Ae chemical behavior of the compounds. 

When you study the reactions of a particular functional group, you need to understand why the functional group reacts the way it does. It is not enough to look at the two reactions shown in Section 5.5 and see that the carbon-carbon double bond reacts with HBr to form a product in which the H and Br atoms have taken the place of the tt bond. You need to understand why the reaction occurs. If you understand the reason for each functional group s reactivity, you will reach the point where you can look at an organic compound and be able to predict the kind of reactions it will undergo. 

Our first three chapters established some fundamental principles concerning the structure of organic molecules and introduced the connection between structure and reactivity with a review of acid-base reactions In this chapter we explore structure and reactivity m more detail by developing two concepts functional groups and reaction mechanisms A functional group is the atom or group m a molecule most respon sible for the reaction the compound undergoes under a prescribed set of conditions How the structure of the reactant is transformed to that of the product is what we mean by the reaction mechanism... 

The value of alkyl halides as starting materials for the preparation of a variety of organic functional groups has been stressed many times In our earlier discussions we noted that aryl halides are normally much less reactive than alkyl halides m reactions that involve carbon-halogen bond cleavage In the present chapter you will see that aryl halides can exhibit their own patterns of chemical reactivity and that these reac tions are novel useful and mechanistically interesting... 

Function 5 provides thermoset reactivity via functional groups such as methacrylates and amines. Function 6 permits the presence of two or three pendent organic groups. This allows all functionality to be controlled to the first-, second-, or third-degree levels. 

Substitution of fluorine into an organic molecule results in enhanced chemical stabiUty. The resulting chemical reactivity of adjacent functional groups is drastically altered due to the large inductive effect of fluorine. These effects become more pronounced as the degree of fluorine substitution is increased, especially on the same carbon atom. This effect demonstrates a maximum in fluorocarbons and their derivatives. 

Adsorption and Surface Chemical Grafting. As with siHca and many other siHcate minerals, the surface of asbestos fibers exhibit a significant chemical reactivity. In particular, the highly polar surface of chrysotile fibers promotes adsorption (physi- or chemisorption) of various types of organic or inorganic substances (22). Moreover, specific chemical reactions can be performed with the surface functional groups (OH groups from bmcite or exposed siHca). 

The carbon bond mechanism (64—66), a variation of a lumped mechanism, spHts each organic molecule into functional groups using the assumption that the reactivity of the molecule is dominated by the chemistry of each functional group. 

AHyl chloride exhibits reactivity as an olefin and as an organic haHde. Its activity as a chloride is enhanced by the presence of the double bond, but its activity as an olefin is somewhat less than that of propylene. AHyl chloride participates in most types of reactions characteristic of either functional group ... 

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