Oxides involving

If adsorption of oxygen on such an oxide involves the process... 

Sections Free radical halogenation and oxidation involve reactions at the benzylic 11 12-11 13 carbon See Table 112... 

Decomposition of adducts such as triphenyl phosphite—ozone provides a convenient method for accomplishing chemical oxidations involving singlet oxygen and making it a useful oxygenating agent for synthetic and mechanistic appHcations. 

Hydroperoxide Process. The hydroperoxide process to propylene oxide involves the basic steps of oxidation of an organic to its hydroperoxide, epoxidation of propylene with the hydroperoxide, purification of the propylene oxide, and conversion of the coproduct alcohol to a useful product for sale. Incorporated into the process are various purification, concentration, and recycle methods to maximize product yields and minimize operating expenses. Commercially, two processes are used. The coproducts are / fZ-butanol, which is converted to methyl tert-huty ether [1634-04-4] (MTBE), and 1-phenyl ethanol, converted to styrene [100-42-5]. The coproducts are produced in a weight ratio of 3—4 1 / fZ-butanol/propylene oxide and 2.4 1 styrene/propylene oxide, respectively. These processes use isobutane (see Hydrocarbons) and ethylbenzene (qv), respectively, to produce the hydroperoxide. Other processes have been proposed based on cyclohexane where aniline is the final coproduct, or on cumene (qv) where a-methyl styrene is the final coproduct. 

Af-Oxides, e.g. (125), were similarly prepared using hydroxylamine to give intermediates such as (124) (79JOC1695, 78H(9)1327), and an alternative synthesis of Af-oxides involves cyclization of 3-acylamino-2-aroylpyridine oximes (126) —> (127) (69MIP21500). 

The UV spectra of thiirane 1-oxide and (15,25)-(+)-2-methylthiirane 1-oxide show a broad maximum at about 205 nm (e —23 000). The latter shows a positive Cotton effect at low energy followed by a negative effect at high energy. The lowest excited states of thiirane 1-oxide involve excitations from the two lone pairs of the oxygen atom (79G19). 2,3-Diphenylthiirene 1-oxide and 1,1-dioxide show absorption due to the 1,2-diphenyl-ethylene chromophore. 

In dry oxidation we quantified the tendency for a material to oxidise in terms of the energy needed, in kj mol of O2, to manufacture the oxide from the material and oxygen. Because wet oxidation involves electron flow in conductors, which is easier to measure, the tendency of a metal to oxidise in solution is described by using a voltage scale rather than an energy one. 

Oxidation Involves a Repeated Sequence of Four Reactions... 

For saturated fatty acids, the process of /3-oxidation involves a recurring cycle of four steps, as shown in Figure 24.10. The overall strategy in the first three steps is to create a carbonyl group on the /3-carbon by oxidizing the C, —C bond to form an olefin, with subsequent hydration and oxidation. In essence, this cycle is directly analogous to the sequence of reactions converting succi-... 

A. Synthesis of Annelated 1,2,4-Triazine 1-Oxides Involving a Nitro Group. 291... 

Many anodic oxidations involve an ECE pathway. For example, the neurotransmitter epinephrine can be oxidized to its quinone, which proceeds via cyclization to leukoadrenochrome. The latter can rapidly undergo electron transfer to form adrenochrome (5). The electrochemical oxidation of aniline is another classical example of an ECE pathway (6). The cation radical thus formed rapidly undergoes a dimerization reaction to yield an easily oxidized p-aminodiphenylamine product. Another example (of industrial relevance) is the reductive coupling of activated olefins to yield a radical anion, which reacts with the parent olefin to give a reducible dimer (7). If the chemical step is very fast (in comparison to the electron-transfer process), the system will behave as an EE mechanism (of two successive charge-transfer steps). Table 2-1 summarizes common electrochemical mechanisms involving coupled chemical reactions. Powerful cyclic voltammetric computational simulators, exploring the behavior of virtually any user-specific mechanism, have... 

A method for the stereospecific synthesis of thiolane oxides involves the pyrolysis of derivatives of 5-t-butylsulfinylpentene (310), and is based on the thermal decomposition of dialkyl sulfoxides to alkenes and alkanesulfenic acids299 (equation 113). This reversible reaction proceeds by a concerted syn-intramolecular mechanism246,300 and thus facilitates the desired stereospecific synthesis301. The stereoelectronic requirements preclude the formation of the other possible isomer or the six-membered ring thiane oxide (equation 114). Bicyclic thiolane oxides can be prepared similarly from a cyclic alkene301. 

Formation of Ester Intermediates. A number of oxidations involve the formation of an ester intermediate (usually of an inorganic acid), and then the cleavage of this intermediate ... 

B. Oxidations involving Cleavage of Carbon-Carbon Bonds... 

Earlier in this chapter, we learned definitions for the terms oxidation and reduction. We saw that oxidation involves an increase in oxidation state. For example, oxidation of a secondary alcohol will produce a ketone ... 

Although fatty acids are both oxidized to acetyl-CoA and synthesized from acetyl-CoA, fatty acid oxidation is not the simple reverse of fatty acid biosynthesis but an entirely different process taking place in a separate compartment of the cell. The separation of fatty acid oxidation in mitochondria from biosynthesis in the cytosol allows each process to be individually controlled and integrated with tissue requirements. Each step in fatty acid oxidation involves acyl-CoA derivatives catalyzed by separate enzymes, utihzes NAD and FAD as coenzymes, and generates ATP. It is an aerobic process, requiring the presence of oxygen. 

Experiments and calculations both indicate that electron transfer from potassium to water is spontaneous and rapid, whereas electron transfer from silver to water does not occur. In redox terms, potassium oxidizes easily, but silver resists oxidation. Because oxidation involves the loss of electrons, these differences in reactivity of silver and potassium can be traced to how easily each metal loses electrons to become an aqueous cation. One obvious factor is their first ionization energies, which show that it takes much more energy to remove an electron from silver than from potassium 731 kJ/mol for Ag and 419 kJ/mol for K. The other alkali metals with low first ionization energies, Na, Rb, Cs, and Fr, all react violently with water. 

The mechanisms of all three oxidations involve initial slow one-equivalent oxidation to a radical (NH20-, -NHOCH3 and N02-) followed either by rapid secondary oxidation (of NH20- or N02 ) or by radical dimerisation (-NHOCHs). 

Swain and Hedberg have shown that the tertiary alcohol is not an intermediate, for the dehydration process is slower than the rate of formation of dye. Instead it is proposed that the tertiary hydrogen is removed to give a radical-cation which is further oxidised to the carbonium ion. The oxidation involves two steps one fast and one very much slower. This parallels the Ce(IV) oxidation of iodide ion and is therefore probably a function of the oxidant. 

CO oxidation involving 5) O exchange suface oxygen PdO -CVPd ... 

From the pH dependence of the peak potential (close to 60 mV/decade), it was proposed that the oxidation involves adsorption of oxygenated species, leading to the formation of either the oxide or the hydroxide ... 

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