Ethylbenzene relative concentration

The greater steric hindrance to acetylation was also shown by a comparison of the rate of (103At2) of acetylation of toluene (0.763), ethylbenzene (0.660), i-propylbenzene (0.606) and f-butylbenzene (0.462) with those (determined by the competition method) for benzoylation both sets of data (Table 112) were obtained with dichloroethane as solvent at 25 °C, all reagent concentrations being 0.1 A/421. Relative rates of acylation other aromatics under the same conditions have also been obtained and are given in Table 113422. The different steric requirements for acetylation and benzoylation are further shown by the following respective relative rates for acylation of naphthalene derivatives in chloroform at 0 °C naphthalene (1 position) 1.00,1.00, (2 position) 0.31,0.04 2,3-dimethylnaphthalene (1 position) 1.59, 172, (5 position) 7.14, 38.2, (6 position) 3.68, 7.7422a. 

The quantity of aromatic contaminants that adsorb onto TiO2 surfaces is also relatively low. d Hennezel and Ollis [47] measured the dark adsorption of the BTEX compounds at a gas-phase concentration of 50 mg/m . Benzene displays the lowest dark adsorption, followed by ethylbenzene. Higher dark adsorption was observed for toluene and xylenes. At 50 mg/m, the dark adsorption of m-xylene was nearly 10 times that of benzene (Table 1). 

Since petroleum products are complex mixtures of hundreds of compounds, the compounds characterized by relatively high vapor pressures tend to volatilize and enter the vapor phase. The exact composition of these vapors depends on the composition of the original product. Using gasoline as an example, compounds such as butane, propane, benzene, toluene, ethylbenzene and xylene are preferentially volatilized (Bauman 1988). Because volatility represents transfer of the compound from the product or liquid phase to the air phase, it is expected that the concentration of that compound in the product or liquid phase will decrease as the concentration in the air phase increases. 

It was established by us earlier, that at the relatively low nickel catalyst concentration the selectivity of the ethylbenzene oxidation into PEH, catalyzed by Ni(L )2 (1,5 lO" mol/1), was sufficiently high = 90%. 

For the reaction of the ethylbenzene oxidation inhibited by BHT the negative contribution of steps with the participation of the quinolide peroxides formed just by the transformations of ortAo-substituted phenols is characteristic. In the case of applying BHT, as a rule, a substantial negative contribution is introduced by the reaction of the phenoxyl radical with the hydroperoxide, the reverse reaction of the peroxyl radical with BHT. At first sight this result seems to be imexpected, so far as the rate constant of the reaction between the ortho-substituted phenoxyl radical and the hydroperoxide is significantly smaller than that of the similar reaction with the ortAo-nonsubstituted phenoxyl radicals. As numerical experiments have shown, the reason is that imlike the ori/ o-nonsubstituted phenols, in the case of the ortAo-substituted phenols the reaction occurs under a kinetic mode with relatively high predominance in the concentration of the phenoxyl radicals over the peroxyl ones. In other words, in the case of BHT the role of the reaction between the phenoxyl radical and the hydroperoxide increases at the expense of the concentration factor. 

Kinetic parameters preexponential factors and activation energies) have been allocated to the particular reaction steps. For reaction (1),(2) and (6) the values were taken from the literature, for the other reactions values have been estimated from analogous approximations (2)- ). These are listed in Table I. Calculations oF the reaction based on the scheme were made and the results compared with the experimental results obtained from the runs carried out in the NPA. Good agreement was obtained for the decrease in ethylbenzene and the Increase in styrene and hydrogen concentrations. In the NPA experiments relatively large amounts of ethylene and benzene were formed at temperatures below 760°C. To take... 

Figures 4—7. Comparison of the decomposition of ethylbenzene and yields of different products or ratios of them in relative molar concentrations at various temperatures in the NPA (9 A experiments at different runs) with...

Studies by Kiersznicki and co-workers demonstrated that chlorosulfonic acid is an effective catalyst in the alkylation of arenes by reaction with alkenes. Benzene, toluene and ethylbenzene were alkylated by propene, elhene and 2-butene in the presence of chlorosulfonic acid which strongly catalysed the alkylations and inhibited polyalkylation. Increasing the concentration of the catalyst enhanced the proportion of /7-isomers in the products. Fluoro-, chloro-and bromobenzenes were similarly alkylated by reaction with C2-C4 alkenes using chlorosulfonic acid as catalyst. The optimum alkylation conditions were with a halobenzene alkene ratio of 1 0.25, a catalyst concentration of 0.33 mol mol" of fluorobenzene and 0.5 mol mol of the other halobenzenes, a temperature of 70 C and a reaction time of 2 hours. Alkylation with propene gave haloisopropylbenzenes the monoalkyl products were obtained as o-, m- and p- mixtures, the relative amounts depended on the quantity of catalyst used and the by-products were dialkyl derivatives, sulfonic acids and sulfones. In the reaction of benzene with propene, fluorosulfonic acid was a more potent alkylation catalyst than chlorosulfonic acid. ... 

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