Toluene oxidation reactions

Reaction. Typical liquid-phase toluene oxidizer reaction conditions may be as follows ... 

The toluene oxidation reaction was used as a probe to study the catalytic properties of the Mo-Ce complex oxides. The as-prepared oxides were introduced into a U-type quartz fixed bed microreactor and their catalytic properties for selective oxidation of toluene to benzaldehyde were evaluated under the reaction conditions of O.lMPa, 400 C, air/toluene = 9 (vol/vol), F/W =1900 ml/h g cat. The reaction products were analyzed by an on-line gas chromatography. Under the above reaction conditions, the main products were CO, CO2, H2O and benzaldehyde. 

Partenheimer showed (ref. 15) that when toluene was subjected to dioxygen in acetic acid no reaction occurred, even at 205 °C and 27 bar. He also showed that when a solution of cobalt(II) acetate in acetic acid at 113 °C was treated with dioxygen ca. 1 % of the cobalt was converted to the trivalent state. In the presence of a substituted toluene two reactions are possible formation of a benzyl radical via one-electron oxidation of the substrate or decarboxylation of the acetate ligand (Fig. 9). Unfortunately, at the temperatures required for a reasonable rate of ArCH3 oxidation (> 130 °C) competing decarboxylation predominates. As noted earlier, two methods have been devised to circumvent this undesirable... 

In continuation of the work on oxidation reactions, Ambulgekar et al. [31] investigated different chemical reactions (oxidation of toluene, (o-/p-/w)-xylenes,... 

Kennedy and Stock reported the first use of Oxone for many common oxidation reactions such as formation of benzoic acid from toluene and of benzaldehyde, of ben-zophenone from diphenyhnethane, of frawi-cyclohexanediol Ifom cyclohexene, of acetone from 2-propanol, of hydroquinone from phenol, of e-caprolactone from cyclohexanone, of pyrocatechol from salicylaldehyde, of p-dinitrosobenzene from p-phenylenediamine, of phenylacetic acid from 2-phenethylamine, of dodecylsulfonic acid from dodecyl mercaptan, of diphenyl sulfone from diphenyl sulfide, of triphenylphosphine oxide from triphenylphosphine, of iodoxy benzene from iodobenzene, of benzyl chloride from toluene using NaCl and Oxone and bromination of 2-octene using KBr and Oxone . Thus, they... 

Species such as cresol are known to be products of the toluene oxidation and have commonly been assumed to be formed via reactions such as (63)... 

Such a reaction mechanism could initiate toluene oxidation and increase the observed removal rates and overall conversion of the toluene. 

Alternatively, some of the reaction intermediates generated during the photocatalytic oxidation of aromatic contaminants may be rather recalcitrant to chlorine radicals, leading to the apparent deactivation phenomenon. Thermodynamically, intermediate species that are recalcitrant toward hydroxyl radicals may be recalcitrant toward chlorine radicals as well (Table 3). The accumulation of these recalcitrant reaction intermediates on the catalyst surface may gradually reduce the effectiveness of chlorine radicals in the photocatalytic system, decreasing the chlorine-promoted enhancement in toluene oxidation to negligible levels [51]. 

The kinetics of the toluene oxidation over Bi2Mo06 and a commercial Bi—Mo—P—O ammoxidation catalyst were investigated by Van der Wiele and Van den Berg [348]. A flow reactor was used at 450—550°C, 1—3 atm and varying feed rate, toluene and oxygen partial pressures. Benzaldehyde formation and combustion reactions are the main process the parallel-consecutive scheme which applies is... 

Group 16 (VIA) Perchlorates. A perchlorate compound perchloryl sulfate, [CAS 43059-05-8], SO GO was produced by the low temperature electrolysis of a I2-WH2SO4 and 3-.VHQ04 solution. This compound is a strong oxidizer reaction with toluene, acetone, benzene, or alcohol at room temperature produces an exothermic and explosive reaction. The S04(C104)2 is soluble in Freon and CC14 without reaction. 

Figure 8.6 shows the effect of water vapor on the formation of C02 and BA for the toluene oxidation. The concentration of C02 increased linearly with the increase in relative humidity. The yield at 60% relative humidity was greater by one order than that in the dry condition. It has been pointed out that the amount of 02 adsorbed under photoillumination is proportional to that of hydroxyl groups (OH-) un the Ti02 surface. The phenomenon has been explained by the following reactions ... 

A similar Te02/HBr catalyst has been used in acetic acid for the oxidation of propene at ca. 120 °C to propene oxide and propene glycol via 1,2-diacetoxypropane.361,362 However, this reaction gives lower yields because of side allylic oxidation reactions. Oxidation of toluene under similar conditions (Te02/LiBr, 160 °C) results in the formation of methylbenzyl acetate mixtures rather than benzyl acetate as observed with Se02/LiBr catalyst (equation 133).363... 

As Haber and Weiss (1934) suggested, at lower H202 concentrations and fixed Fe2+ the oxidation reaction approaches second order however, when the ratio of H202 Fe2+ increases, the reaction kinetic approaches zero order and the reaction process depends on the competition between hydroxyl radicals and superoxide radicals. If an excess of hydrogen peroxide is present, then the reactions as shown in Equation (6.123) and Equation (6.124) for 2,4-dinitrotoluene are dominant. The amount of H202 was used up quickly in this study, indicating the importance of Equation (6.123). At concentrations of Fe2+ greater than 600 mg/L, the DRE of BTX reached a maximum value at approximately 82% for benzene and toluene and 73% for xylene. 

The deselelenation reaction of heterocycle 202 with triphenylphosphine followed by addition of mesitonitrile oxide results in the formation of product 203 in 83% yield (Scheme 12) <1995JOM43>. This compound is thermally very stable and does not decompose even at 200 °C in toluene. This reaction has been extended to the use of Tbt(Ditp)Sn=E, Tbt(Dmtp)Sn=S, and Tbt(Tcp)Sn=E precursors (E = S, Se) in the reaction with mesytonitrile oxide (Ditp = 2,2"-diisopropyl-/ -terphenyl-2 -yl Dmtp = 2,2"-dimethyl- z-terphenyl-2 -yl Tcp = 2,4,6-tricyclohexyl-phenyl) <2004JA15572>. 

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