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Phenol degradation reaction

Figure 27.4 Comparison between homogenous (Na4Wio032 4 x 10 M) and heterogeneous (PVDF-Wio 25.0 wt%) phenol degradation reaction. (Adapted from Fontananova et al., 2006b.)... Figure 27.4 Comparison between homogenous (Na4Wio032 4 x 10 M) and heterogeneous (PVDF-Wio 25.0 wt%) phenol degradation reaction. (Adapted from Fontananova et al., 2006b.)...
In addition to stabilisers, antioxidants and ultra-violent absorbers may also be added to PVC compounds. Amongst antioxidants, trisnonyl phenyl phosphite, mentioned previously, is interesting in that it appears to have additional functions such as a solubiliser or chelator for PVC insoluble metal chlorides formed by reaction of PVC degradation products with metal stabilisers. Since oxidation is both a degradation reaction in its own right and may also accelerate the rate of dehydrochlorination, the use of antioxidants can be beneficial. In addition to the phenyl phosphites, hindered phenols such as octadecyl 3-(3,5-di-tcrt-butyl-4-hydroxyphenyI)propionate and 2,4,6-tris (2,5-di-rcrt-butyl-4-hydroxybenzyl)-1,3,5-trimethylbenzene may be used. [Pg.330]

Phenolic degradation, thermal and thermo-oxidative, 418-425 Phenolic-epoxy networks, 413 Phenolic monomers, second-order reaction rate constants of formaldehyde with, 403... [Pg.593]

Phenol is an important intermediate in the anaerobic degradation of many complex and simple aromatic compounds. Tschech and Fuchs proposed that the carboxylation of phenol to 4-hydroxybenzoate is the first step in the degradation of phenol under denitrifying conditions. However, 4-hydroxybenzoate is not detected in the cultures or cell extracts of the denitrifying Pseudomonas species in the presence of CO2 and phenol, but it is detected if phenol is replaced by phenolphosphate. In contrast, 4-hydroxybenzoate is readily detected as an intermediate of phenol degradation in the iron-reducing bacterium GS-15, and 4-hydroxybenzoate may prove to be a common intermediate in the anaerobic transformation. Thus, in anaerobic degradation of phenolic compounds, it has been postulated that carboxylation reactions may play important roles. [Pg.84]

Chauaqui et al (10) show that y irradiation of two types of kraft lignin with about 2.4 Mrad of dose leads to polymerization materials. High dose of 10 Mrad are required to induce degradation reactions with loss of methoxyl groups. Their results indicate that the most important free radicals formed involved phenolic hydroxyl groups, a carbonyl groups and a ethylenic double bonds. Unfortunately the dose rate used was not reported. [Pg.168]

Calcined temperature. Based on the degrading reaction of the component in dipping solution, temperatures of 400°C, 500°C, 600°C, 700°C, and 800°C were tested at the same pyrolysis time. From the results for phenol degradation (Fig. 14.2), a similar degradation results obtained at the pyrolysis temperature 500°C and 600°C. [Pg.327]

Phenols and phenol ethers may also be converted to quinones directly,488 an example being 2,3,5-trimethylphenol to 2,3,6-trimethylbenzoquinone, an intermediate in vitamin E production. Ring-opening and degradation reactions are... [Pg.164]

This feature implies that the phenol degradation kinetics did not change in the course of the runs due to the accumulation of intermediate products in the reaction ambient. As a consequence, only the phenol concentration values relative to conversion below 60% have been taken into account in the course of photoadsorption modeling. [Pg.21]

By contrast, in the case of the degradation of phenol, all reaction intermediates are formed throngh the oxidative pathway only by reaction of phenol with the OH radicals generated on the surface of the photocatalyst by hole trapping. Therefore the selectivity is spectrally invariant (eq. 5.140 and Fig. 5.49). Also noteworthy is the ratio of the two selectivities for the formation of BQ and ClCat, Sb(JSc ch. , which scales with /(eq. 5.141). This means that the spectral variation of this ratio reflects the spectral variation of the ratio between the electron and hole concentrations on the photocatalyst surface. The ratio /is given by eq. 5.142, where p is the ratio LJI of the diffusion lengths of electrons and holes, and B is a constant. [Pg.371]

Mn oxides are versatile oxidants. They can oxidize to Co, Cr to (chromate), As to As, and phenols and aromatic amines to polymeric products. Some of the organic degradation reactions are discussed in more detail in Chapter... [Pg.269]


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See also in sourсe #XX -- [ Pg.707 ]




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Phenol reactions

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