Addition reactions theoretical aspects

Alkylation reactions reveal a mechanistic aspect of the cuprate reactions different from that of addition reactions. Theoretical analyses of reactions of alkyl halides (Mel and MeBr) [123, 124] and epoxides (ethylene oxide and cyclohexene oxide) [124] with lithium cuprate clusters (Me2CuLi dimer or Me2CuLi-LiCl, Scheme 10.11) resolved long-standing questions on the mechanism of the alkylation reaction. Density functional calculations showed that the rate-determining step of the... 

In Chap. 2, the analysis of diffusion-limited reaction rates of Smolu-chowski, Collins and Kimball, and that of Noyes is followed. The considerable literature on reaction rates between solute species is also presented. Additional and important other factors which influence the rate of reaction are a coulomb interaction between reactants, long-range energy or electron transfer and an angular dependence of the rate of reaction. These topics are considered in the Chaps. 3—5. The experimental and theoretical work are compared and contrasted. When the reactants are formed in pairs (by bond fission of a precursor), the rate or probability of recombination can be measured and is of considerable interest. Chapters 6 and 7 discuss the theoretical aspects of the recombination of neutral and ionic radical pairs and also appeal to the extensive literature on the experimentally measured rate of recombination. The weaknesses of this theoretical... 

M. T. Reetz, Structural, Mechanistic, and Theoretical Aspects of Chelation-Controlled Carbonyl Addition Reactions, Ace. Chem. Res. 1993, 26, 462M68. 

Cool flames are difficult subjects for quantitative study since the time scale of events is generally too short to allow the use of conventional sampling. In addition, their non-isothermal character (which implies rate coefficients which change as reaction progresses) makes it difficult to develop theoretical models which satisfactorily describe the more important features (the periodicity and temperature rise). It is outside the scope of this review to discuss the more general theoretical aspects of cool-flame phenomena, and the reader is referred to VoL 2, Chap. 2 of this Series and also to the work of Yang and Gray [113], Halstead et al. [114, 115] and others [112,116,117]. 

This chapter provides in troductory material that applies to all types of titrimetric methods of analysis, using precipitation titrimetry to illustrate the various theoretical aspects of the titration process. Chapters 14, 15, and 16 are devoted to the various types of neutralization titrations, in which the analyte and titrants undergo acid/base reactions. Chapter 17 provides information about titrations in which the analytical reactions involve complex formation. These methods are of particular importance for the determination of a variety of cations. Finally, Chapters 18 and 19 are devoted to volumetric methods, in which the analytical reactions involve electron transfer. These methods are often called redox titrations. Some additional titration methods are explored in later chapters. These methods include ampero-metric titration, in Section 23B-4, and spectrophotometric titrations, in Section 26A-4. 

In addition to rate constant measurements and mechanistic determinations for reactions of radical species, pulse radiolysis techniques have been especially successful in measurements of one-electron reduction potentials of redox pairs where one of the partners is unstable so that traditional methods cannot be used. The reduction potentials of a large number of species, in various solvents, have been determined. The techniques and theoretical aspects have been presented by Pedi Neta in the Journal of Chemical Education (2). 

Reactions of metal complexes with saturated hydrocarbons are very important not only from the standpoint of applications but are also extremely interesting for theoretical chemistry. So it is not surprising that many papers devoted to the theoretical aspects of C-H bond activation and especially oxidative addition of C-H compounds to metal complexes (as well as ions and atoms), have been published in recent decades. Some of their results are summarized in books [ 1 ] and reviews [2]. 

The theme here is electron transfer, in inner- and outer-sphere reactions and, to a lesser degree, in related processes like optically induced charge transfer or excited state decay. Three books have been written on electron transfer, by Reynolds and Luniry, Cannon and Ulstrup, the last of which emphasizes theoretical aspects. In addition, a series of theoretical and experimental articles appear in the book Tunneling in Biological Systems , edited by Chance et and in volume 74 (1982) of the Faraday Discussions of the Chemical Society. A number of reviews have appeared, dealing both with general aspects - and more specialized themes, and many will be referred to in the sections that follow. 

Since the theoretical aspect of heterocycles is a new addition to this series, it is discussed here in greater detail. Although eight-membered aza heterocycles have been known since 1906, theoretical studies on these systems only occurred from 1960. The conformational property of eight-membered aza heterocycles is also of utmost importance in understanding their synthesis and reactions. 

J. D. Cox and G. Pilcher, Thermochemistry of Organic and Organometallic Compounds, Academic Press, London New York, 1970. The major feature is a tabulation of experimental measurements of A H°, heats of reaction, for organic and organometallic compounds. Values of AfH° are derived for each experimental result where phase changes are involved measurements of AH (heat of vaporization) are tabulated. Experimental uncertainties are assessed. Introductory chapters discuss the basics of thermochemistry, the types of experimental measurements involved, their accuracies and limitations. Additional chapters examine theoretical aspects of thermochemistry and various schemes for relating thermochemical properties to structural parameters. 

Rhodium-catalyzed carbonylation of methanol is known as the Monsanto process, which has been studied extensively. From the reaction mechanism aspect, the study of kinetics has proved that the oxidative addition of methyl iodide to the [Rh(CO)2l2] is the rate-determining step of the catalytic cycle. It was also observed that acetyl iodide readily adds to [Rh(CO)2l2], indicating that the acetyl iodide must be scavenged by hydrolysis in order to drive the overall catalytic reaction forward. An alternative to sequential reductive elimination and the hydrolysis of acetyl iodide is the nucleophilic attack of water on the Rh acetyl complex and the production of acetic acid. The relative importance of these two alternative pathways has not yet been fully determined, although the catalytic mechanism is normally depicted as proceeding via the reductive elimination of acetyl iodide from the rhodium center. The addition of iodide salts, especially lithium iodide, can realize the reaction run at lower water concentrations thus, byproduct formation via the water gas shift reaction is reduced, subsequently improving raw materials consumption and reducing downstream separation. In addition to the experimental studies of the catalytic mechanism, theoretical studies have also been carried out to understand the reaction mechanism [17-20]. 

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