Activation of benzene

Fig. 108.—The activity of benzene in solution with rubber plotted against the volume fraction of rubber. The solid curve represents smoothed experimental data of Gee and Treloar. The upper dashed curve represents the calculated ideal curve for an ideal solution of a solute with M = 280,000 dissolved in benzene. The diagonal dashed curve corresponds to ai — Vi. (From the data of Gee and Treloar. )...

A related base-promoted C-H activation of benzene by Pt(II) was recently reported. With the tridentate monoanionic amido pineer ligand N3 , the triflate complex N3 Pt(OTf), depicted in Scheme 8 was shown to activate benzene in the presence of base (35). It was noted that the chloro complex N3 PtCl was not reactive under these conditions. The activity of the triflate complex again appears to result from the higher lability of triflate which can allow for coordination of the hydrocarbon. 

Morimoto K, Wolff S, Koizumi A. 1983. Induction of sister-chromatid exchanges in human lymphocytes by microsomal activation of benzene metabolites. Mutat Res 119 355-360. 

Figure 6.29 Metabolic activation of benzene to reactive metabolites, which may damage bone marrow and other tissues.

A large number of studies have been performed on the effects of hydroquinone on bone marrow, in order to elucidate the mechanisms of the myelodepressive and leukae-mogenic activity of benzene. 

M. (1996) The role of CYP2E1 and 2B1 in metabolic activation of benzene derivatives. Arch. 

The activation energy is roughly twice as large for the alloys as for pure nickel. Lyubarski (70S) was the first to show that the specific activity of benzene hydrogenation decreases upon alloying of nickel with copper. He found, however, an initial rise in activity on plotting the activity as a function of weight of the catalysts. 

Decarbonylation of a-acyliron complexes by photolysis (Section 3.5) is the primary method for the preparation of a-aryliron complexes. Alternatively, cr-aryliron complexes can be prepared by the method of Beletskaya from FpNa (5). For example, the /7-tolyl analog has been recently prepared in order to study the C H activation of benzene (equation 3). ... 

An alternative to the coupling of olefins with aryl halides is C-H activation of benzenes and addition to alkynes. A Pd" catalyst was shown to catalyze this reaction in an acidic medium such as CF3COOH, even at room temperature (eq. (17)) [83],... 

A very recent example of an enantioselective C-H activation has been reported by Bergman. A chiral metal complex was employed in several C-H activation reactions, as shown in Scheme 3. Activation of benzene results in the formation of a 1 1 mixture of possible diasteriomers. Activation of cyclohexane, however, gives only a single diasteriomer. Subsequent thermolysis of the sample at 150°C... 

In 1983, Watson reported that Lu(III) and Y(III) methyl complexes mediate C—H activation of benzene and methane.59 For benzene activation, Cp 2Lu(Me), which is in equilibrium with the species Cp 2 Lu (,u - Me)Lu (Me)Cp 2, reacts to release methane and produce Cp 2Lu(Ph) (Equation 11.7). Kinetic studies revealed a rate equation — d[Lu-Me] = (ki + fc2[C6H6])[Lu-Me] that is consistent with two... 

Among four different supports, a - AI2O3, y - AI2O3, Kieselguhr and MgO, nickel on a-Al203 is the best choice for catalytic hydrogenation of benzene. The activity of benzene hydrogenation increases with the increase of nickel concentration upto 40% NiO, after which increase of concentration the opposite trend is noticed. Similarly, an optimum value of nickel dispersion, metal area and its crystallite size have also been observed. 

---