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Page: 287 The gases released during volcanic eruptions contain large amounts of organohalides, including chloromethane, chloroform, dichlorodifluoromethane, and many others.
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Page: 290 FIGURE 10-1 Mechanism of the radical chlorination of methane. Three kinds of steps are required: initiation, propagation, and termination. The propagation steps are a repeating cycle, with Cl· a reactant in step 1 and a product in step 2, and with ·CH3 a product in step 1 and a reactant in step 2. (The symbol hv shown in the initiation step is the standard way of indicating irradiation with light.)
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Page: 293 FIGURE 10-2 Mechanism of allylic bromination of an alkene with NBS. The process is a radical chain reaction in which (1) a Br· radical abstracts an allylic hydrogen atom of the alkene and gives an allylic radical plus HBr. (2) The HBr then reacts with NBS to form Br2, which (3) reacts with the allylic radical to yield the bromoalkene product and a Br· radical that continues the chain.
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Page: 294 FIGURE 10-3 An orbital view of the allyl radical. The p orbital on the central carbon can overlap equally well with a p orbital on either neighboring carbon, giving rise to two equivalent resonance structures.
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Page: 295 FIGURE 10-4 The spin density surface of the allyl radical locates the position of the unpaired electron and shows that it is equally shared between the two terminal carbons.
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Page: 302 FIGURE 10-5 Mechanism of the Suzuki–Miyaura coupling reaction of an aromatic boronic acid with an aromatic halide to give a biaryl. The reaction takes place by (1) reaction of the aromatic halide, ArX, with the catalyst to form an organopalladium intermediate, followed by (2) reaction with the aromatic boronic acid. (3) Subsequent decomposition of the diarylpalladium intermediate gives the biaryl product.
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Page: 304 FIGURE 10-6 Oxidation levels of some common types of compounds.
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Page: 306 Marine corals secrete organohalogen compounds that act as a feeding deterrent to fish.
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