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Ionic reactions elimination

Ionic Reactions—Nucleophilic Substitution and Elimination Reactions of Alkyl Halides... [Pg.221]

Because an important reason for studying ionic reactions in the gas phase, rather than in the condensed phase, is to eliminate the strong moderating effects of the solvent, it is generally desirable that the buffer gas serve only as a chemically inert physical medium in which the reactants are suspended and thermalized. In the VHP... [Pg.227]

The Barton-McCombie deoxygenation reaction was invented for use in the manipulation of aminoglycoside antibiotics. It has become a popular method because of the mild conditions employed. Radical reactions have advantages over ionic reactions for carbohydrate chemistry. In this context, there is little neighboring group interference in cationic reactions and little elimination compared with normal nucleophilic displacement reactions. [Pg.154]

This problem is not so severe when acyl xanthates are used as precursors because these substrates absorb in the visible region, while the products do not (however, the products might still be recycled to the radical pool by radical addition-elimination). Visible light photolysis of benzoyl xanthane (42) and allyl acetate provides (43) in 60% yield. Standard (ionic) 3-elimination of the xanthane is a facile reaction that gives (44). When the tertiary acyl xanthane (45) is irradiated in the presence of W-benzylmaleimide... [Pg.749]

The cyclobutene 14 used a few pages back in a cycloaddition was actually made by an ionic reaction from adipic acid 34. Double bromination of the acid chloride and quenching with methanol gives 35 that cyclises12 to 14 with NaH. Presumably one enolate is alkylated by the other bromide and then the second enolate eliminates 36 to give 14. [Pg.248]

The effect of electrical fields on the radiolysis of ethane has been examined by Ausloos et and this study has shown that excited molecules contribute a great deal to the products. The experiments were conducted in the presence of nitric oxide, and free-radical reactions were therefore suppressed. The importance of reactions (12)-(14) was clearly demonstrated by the use of various isotopic mixtures. Propane is formed exclusively by the insertion of CH2 into C2H6 and the yield is nearly equal to the yield of molecular methane from reaction (14). Acetylene is formed from a neutral excited ethane, probably via a hot ethylidene radical. Butene and a fraction of the propene arise from ion precursors while n-butane appears to be formed both by ionic reactions and by the combination of ethyl radicals. The decomposition of excited ethane to give methyl radicals, reaction (15), has been shown by Yang and Gant °° to be relatively unimportant. The importance of molecular hydrogen elimination has been shown in several studies ° °. ... [Pg.122]

Figure 4.4 An aqueous ionic reaction and its equations. When silver nitrate and sodium chromate solutions are mixed, a reaction occurs that forms solid silver chromate and a solution of sodium nitrate. The photos present the macroscopic view of the reaction, the view the chemist sees in the lab. The blow-up arrows lead to an atomic-scale view, a representation of the chemist s mental picture of the reactants and products. (The pale ions are spectator ions, present for electrical neutrality, but not involved in the reaction.) Three equations represent the reaction in symbols. (The ions that are reacting are shown in red type.) The molecular equation shows all substances intact. The total Ionic equation shows all soluble substances as separate, solvated ions. The net Ionic equation eliminates the spectator ions to show only the reacting species. Figure 4.4 An aqueous ionic reaction and its equations. When silver nitrate and sodium chromate solutions are mixed, a reaction occurs that forms solid silver chromate and a solution of sodium nitrate. The photos present the macroscopic view of the reaction, the view the chemist sees in the lab. The blow-up arrows lead to an atomic-scale view, a representation of the chemist s mental picture of the reactants and products. (The pale ions are spectator ions, present for electrical neutrality, but not involved in the reaction.) Three equations represent the reaction in symbols. (The ions that are reacting are shown in red type.) The molecular equation shows all substances intact. The total Ionic equation shows all soluble substances as separate, solvated ions. The net Ionic equation eliminates the spectator ions to show only the reacting species.
A molecular equation for an aqueous ionic reaction shows undissociated substances. A total Ionic equation shows all soluble Ionic compounds as separate, solvated ions. Spectator ions appear unchanged on both sides of the equation. By eliminating them, you see the actual chemical change in a net ionic equation. [Pg.115]

The last two chapters introduced pericyclic reactions, and the next one will cover reactions of radicals. Together with the ionic reactions which have been the subject of most of this book, these three classes cover all organic mechanisms. But before we move on to consider radicals, we need to fill a gap in our coverage of ionic reactions. You have met the most important types of ionic reactions—additions, substitutions, and eliminations. But two remain and they are closely related, in rearrangements the molecule changes its carbon skeleton and in fragmentations the carbon skeleton splits into pieces. We lead up to these types of reaction by looking at a phenomenon known as participation. [Pg.931]

Elimination reactions ch17 to those of ionic reactions Polymerization web... [Pg.970]


See other pages where Ionic reactions elimination is mentioned: [Pg.67]    [Pg.241]    [Pg.155]    [Pg.233]    [Pg.66]    [Pg.607]    [Pg.65]    [Pg.290]    [Pg.393]    [Pg.155]    [Pg.99]    [Pg.67]    [Pg.306]    [Pg.637]    [Pg.415]    [Pg.1013]    [Pg.49]    [Pg.357]    [Pg.280]    [Pg.207]    [Pg.27]   
See also in sourсe #XX -- [ Pg.191 ]




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