Phenanthrene reaction with ozone

The reaction of ozone with an aromatic compound is considerably slower than the reaction with an alkene. Complete ozonolysis of one mole of benzene with workup under non-oxidative conditions will yield three moles of glyoxal. The selective ozonolysis of particular bonds in appropriate aromatic compounds is used in organic synthesis, for example in the synthesis of a substituted biphenyl 8 from phenanthrene 7 ... 

The resonance energies of fused systems increase as the number of principal canonical forms increases, as predicted by rule 6 (p. 35).75 Thus, for benzene, naphthalene, anthracene, and phenanthrene, for which we can draw, respectively, two, three, four, and five principal canonical forms, the resonance energies are, respectively, 36, 61, 84, and 92 kcal/mol (152, 255, 351, and 385 kJ/mol), calculated from heat-of-combustion data.76 Note that when phenanthrene, which has a total resonance energy of 92 kcal/mol (385 kJ/mol), loses the 9,10 bond by attack of a reagent such as ozone or bromine, two complete benzene rings remain, each with 36 kcal/mol (152 kJ/mol) that would be lost if benzene was similarly attacked. The fact that anthracene undergoes many reactions across the 9,10 positions can... 

Beltran et al. (1995) concluded that (1) the UV/ozone oxidation process can achieve high removal rates of fluorene, phenanthrene, and acenaph-thene, with total efficiencies being near 100% in some cases (2) neutral pH of 7 yields the highest removal rate of fluorene in solution and (3) the greater the bicarbonate concentration added to fluorene, the lower the removal efficiency becomes. When an excess of ozone is present in the reaction mixture, the degradation rate of anthracene, phenanthrene, and pyrene can be given as ... 

In an attempt to determine the atmospheric oxidation processes that would result in an arene oxide functional group in PAHs, Murray and Kong (1994) studied the reaction of particle-bound PAHs with oxidants derived from the reactions of ozone with alkenes. Phenanthrene and pyrene were converted to arene oxides under these simulated atmospheric conditions. Control experiments indicated that the oxidant responsible for the transformation was not ozone, but a product of the reaction of ozone with tetramethylethylene (TME), probably the carbonyl oxide or the dioxirane derived from TME. 

Some aromatic compounds can also react with ozone, although most simple aromatic rings such as benzene derivatives and naphthalene do not. Anthracene reacts with ozone to give anthraquinone in 73% yield after an oxidative workup. Indeed, quinone formation is a more typical example of the reaction of ozone with aromatic compounds (for other oxidative cleavage reactions see sec. 3.8 and for oxidation to phenols and quinones see sec. 3.3). Only a reactive n bond, such as the 9,10 bond of phenanthrene, will oxidatively cleave, and phenanthrene (361) was oxidized to dialdehyde 362 upon treatment with ozone in methanol followed by a workup with potassium iodide in acetic acid. ... 

Polycyclic hydrocarbons are extremely reactive with ozone. For example, naphthalene reacted with ozone at a rate about 1500 times faster than benzene (Hoigne and Bader, 1983b), and higher polycyclic hydrocarbons such as phenanthrene, pyrene, and benzo[a]pyrene were also extremely reactive (Butkovic et al., 1983). The experiments of Hoigne and Bader also indicate that the rate constants for reaction of ozone with aromatic hydrocarbons in water were about 100 times greater than in nonpolar solvents such as CCI4. However, aliphatic compounds did not show such a profound solvent effect. 

H2SO4, H2O2 [8] or KM11O4. The simplest, cheapest and most convenient process is air oxidation, which is an exothermic reaction. Air enriched with ozone does permit lower temperatures (60-70°C) to be used initially and could promote crosslinking similar to the ozonization of phenanthrene in solution [9]. 

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