Some Important Examples

Many biological reactions involve initial binding of a carbonyl compound to an enzyme or coenzyme via mine formation The boxed essay Imines in Biological Chemistry gives some important examples... 

There are obviously many reactions that are too fast to investigate by ordinary mixing techniques. Some important examples are proton transfers, enzymatic reactions, and noncovalent complex formation. Prior to the second half of the 20th century, these reactions were referred to as instantaneous because their kinetics could not be studied. It is now possible to measure the rates of such reactions. In Section 4.1 we will find that the fastest reactions have half-lives of the order 10 s, so the fast reaction regime encompasses a much wider range of rates than does the conventional study of kinetics. 

This part of the presentation embodies first a general treatment on surfactants followed by the elaboration of frothers, collectors and regulators. The text subsequently involves the area of sulfide flotation, which occupies a premier position in the field of flotation. The section is completed with some important examples of flotation of sulfides. The final section is devoted to natural hydrophobicity which, on its own accord constitutes an important and interesting area in the field of flotation. 

Numerous substituted derivatives of chitin and chitosan are known [67] some important examples are shown in Scheme 10.9. The possibility of forming either anionic (5,7,8,11) or cationic (9,12) derivatives should be noted. The O-carboxymethyl (5) and N-carboxymethyl (11) polymers are of particular interest as they have stronger complex-forming capabilities with metal ions than either unsubstituted chitosan or EDTA [65]. In practice, derivatives formed by substitution via the 2-amino group of chitosan are more common than those substituted via the 6-hydroxy position of the glucopyranose grouping [65]. 

Table 4.7 Some important examples of the dominant role played by phosphorus in biochemistry. With permission of F. H. Westheimer (1987)...

Finally, let us look at some important examples in which asymmetric cyclopropanation reactions are used in the asymmetric construction of subunits of biologically active organic molecules. 

In recent years, such a variety of dendrimer syntheses have been described in the literature, that they cannot all be mentioned in this essay. Many reviews have been published, reflecting the enormous attention which has been given to dendri-mers.[41 The general architectural and synthetical concepts of dendrimer chemistry can, however, be explained by some important examples. 

Derivatives of 1,4- and 1,5-diaminoanthraquinone provide some important examples in this class. Relatively simple dyes include Cl Vat Yellow 3 (6.61 X = H) and Cl Vat Violet 15 (6.61 X = OH). 

Some important examples of real radiation sources with spectral distributions close to the Planck distribntion are the sun (which shows a spectrum consistent with T = 6000 K) and the bright tnngsten wire of a light bulb T = 2800 K). 

Some important examples of nucleophilic addition-elimination... 

Aliphatic polyesters are one of the important classes of biodegradable pol3nners. Some important examples are given below ... 

The commercial availability of basic pyridine derivatives has encouraged a tremendous amount of research into pharmaceutically active compounds. Two reviews in particular list a large number of medicinal compounds (B-80MI20900,77CZ389) based on the pyridine ring. Likewise, the occurrence of benzopyridine natural products with chemotherapeutic activity has stimulated the production of synthetic materials from aromatic amine precursors. Some important examples are presented below. 

There are undesirable and unavoidable pharmacological effect of the drug, which occur at therapeutic dose. These unwanted effects of many drugs are based on their pharmacological actions. Some important examples are ... 

In addition to fuel and oxidizer, other additives are as important to the final formulation as the fuel-oxidizer system, and their role, along with some important examples, is as follows. 

Zeolite catalysts in many forms are used for important commercial processes. The studies were extended to L zeolites, mordenite, erionite, and dealuminated faujasites and mordenites. More attention is paid now to zeolites with univalent and multivalent cations and to multicomponent catalysts. Among these some important examples are the tellurium-containing catalyst for hydrocarbon dehydrocyclization (42), the difunctional Ni- and Pd-zeolite catalysts for benzene hydrodimerization to phenylcyclohexane (42), the catalyst for the hydrogenation of phenol cyclohexanol (44), the 4% Ni/NaY which forms butanol, 2-ethylhexanol, 2-ethylhexanal, and 2-ethylhexanol from a mixture of n-butyraldehyde and hydrogen. 

In general, special terminology for reactions is to be discouraged. However, certain catalytic processes of technological interest have special names in common use. Where such processes involve the simultaneous occurrence of two or more different chemical reactions, special names for the processes are probably inevitable. Some important examples of such processes of technological interest are ... 

Although it would be inappropriate to attempt a comprehensive survey of this topic, it may nevertheless be helpful if some important examples of recent work are mentioned. 

In this chapter, some important examples of integrated membrane systems will be presented starting from the most well-known application of membrane technology, that is, water desalination. 

Many less electropositive metals known as chalcophiles are found commonly as sulphide minerals some important examples are pyrites (FeS2), sphalerite (zinc blende, ZnS), molybdenite (MoS2), cinnabar (HgS) and galena (PbS). Volatile sulphur compounds such as H2S and organic compounds are also found... 

THE MOST IMPORTANT TYPES OF COMPLEXES APPLIED IN QUALITATIVE ANALYSIS In qualitative inorganic analysis complexes (both ions and molecules) are often encountered. Some important examples of these are ... 

Problems in Practical Use of Mycoherbicides. Despite the promise held by mycoherbicides and the experimental successes achieved to date, several biological, technological, and economic problems exist which may limit the practical utiliMtion of this technology. The following are some important examples. 

Finally, some important examples emphasizing the versatility and synthetic utility of dipolar non-HBD solvents as reaction media will be given. 

Some important examples of the application of NMR spectroscopy in S-N chemistry include (a) investigations of the (NSC1)3 3NSC1 equilibrium in solution and... 

Technically it is the existence of transcendental numbers in the number continuum that makes chaos possible. We should note, however, that this does not prevent meaningful computer exploration of chaos despite the fact that computers only deal in rational approximations to algebraic and transcendental numbers (see, e.g., Hammel et al. (1987)). This fact is illustrated in Section 2.2, where we discuss some important examples of chaotic mappings. 

Like their metal acycloalkane analogs, the chemical behavior of the unsaturated species is quite different from the corresponding heterocycles without a metal atom. Metallacycloalkenes appear also as reactive intermediates, e.g., in alkyne trimerization or cotrimerization with heterosystems or in alkyne metathesis. Some important examples are given in the following sections. 

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