Reaction benzene production

Modification of the Erlenmeyer reaction has been developed using imines of the carbonyl compounds, obtained with aniline," benzylamine or n-butylamine. Ivanova has also shown that an A-methylketimine is an effective reagent in the Erlenmeyer azlactone synthesis. Quantitative yield of 19 is generated by treatment of 3 equivalents of 2-phenyl-5(4ff)-oxazolone (2) (freshly prepared in benzene) with 1 equivalent of iV-methyl-diphenylmethanimine (18) in benzene. Products resulting from aminolysis (20), alkali-catalyzed hydrolysis (21), and alcoholysis (22) were also described. 

Reaction Relative Rate toluene/ benzene Product Distribution (%) ... 

It has become clear that benzoate occupies a central position in the anaerobic degradation of both phenols and alkylated arenes such as toluene and xylenes, and that carboxylation, hydroxylation, and reductive dehydroxylation are important reactions for phenols that are discussed in Part 4 of this chapter. The simplest examples include alkylated benzenes, products from the carboxylation of napthalene and phenanthrene (Zhang and Young 1997), the decarboxylation of o-, m-, and p-phthalate under denitrifying conditions (Nozawa and Maruyama 1988), and the metabolism of phenols and anilines by carboxylation. Further illustrative examples include the following ... 

The catalytic activity of Mg/Al/O sample in m-cresol gas-phase methylation is summarized in Figure 1, where the conversion of m-cresol, and the selectivity to the products are reported as a function of the reaction temperature. Products were 3-methylanisole (3-MA, the product of O-methylation), 2,3-dimethylphenol and 2,5-dimethylphenol (2,3-DMP and 2,5-DMP, the products of ortho-C-methylation), 3,4-dimethylphenol (3,4-DMP, the product of para-C-methylation), and poly-C-methylated compounds. Other by-products which formed in minor amounts were dimethylanisoles, toluene, benzene and anisole (not reported in the Figure). 

Formation of cuprene is either by a free-radical chain reaction or by clustering around the parent ion (cluster size 20) followed by neutralization, which is not a chain process. The M /N value for decomposition of acetylene is about 20, giving the corresponding G value as 70-80, which is very large. The G value of benzene production is 5, whereas the G of conversion of monomers into the polymer is 60. 

The synergism of a dual-catalyst system comprising of Pt/ZSM-12 and H-Beta aiming to improve the benzene product purity during transalkylation of aromatics has been studied. Catalyst compositions of the dual-catalyst system were optimized at various reaction temperatures in terms of benzene product purity and premium product yields. Accordingly, a notable improvement in benzene purity at 683 K that meets the industrial specification was achieved using the cascade dual-bed catalyst. 

All three chlorine atoms of chloroform take part in the Friedel-Crafts reaction the product of the reaction with benzene is the important hydrocarbon triphenylmethane, the parent substance of the well-known class of dyes. Paraleucaniline, [(p) NH2.C6H4]3CH, has been converted into triphenylmethane by reductive hydrolysis of its tris-diazo-com-pound (E. and 0. Fischer). 

In the ideal biphasic hydrogenation process, the substrate will be more soluble or partially soluble in the immobilization solvent and the hydrogenation product will be insoluble as this facilitates both reaction and product separation. Mixing problems are sometimes encountered with biphasic processes and much work has been conducted to elucidate exactly where catalysis takes place (see Chapter 2). Clearly, if the substrates are soluble in the catalyst support phase, then mixing is not an issue. The hydrogenation of benzene to cyclohexane in tetrafluoroborate ionic liquids exploits the differing solubilities of the substrate and product. The solubility of benzene and cyclohexane has been measured in... 

Hydrogenation of Benzene Benzene hydrogenation is a facile reaction and is indicative of the number of surface Ni atoms available for catalysis. The activity of the catalysts in the benzene hydrogenation reaction was investigated at 453 Cyclohexane was the only product of the reaction. Benzene conversion (Table 11.4) increased with increasing Ni content (samples 2A—4A) up to 20 wt.%. 

The proposed mechanism involves either path a in which initially formed ruthenium vinylidene undergoes nonpolar pericyclic reaction or path b in which a polar transition state was formed (Scheme 6.9). According to Merlic s mechanism, the cyclization is followed by aromatization of the ruthenium cyclohexadienylidene intermediate, and reductive elimination of phenylruthenium hydride to form the arene derivatives (path c). A direct transformation of ruthenium cyclohexadienylidene into benzene product (path d) is more likely to occnir through a 1,2-hydride shift of a ruthenium alkylidene intermediate. A similar catalytic transformation was later reported by Iwasawa using W(CO)5THF catalyst [14]. 

Purification. Small amounts of reaction by-products are produced during the liquid-phase oxidation of toluene. These by-products include acetic and formic acids, benzene, benzaldehyde, benzyl alcohol, aliphatic benzyl esters such as benzyl formate and benzyl acetate, biphenyl, 2-, 3-, and 4-methylbiphenyls, and phthalic acid. Of these only benzaldehyde and benzene [71 -43-2] are currendy separated commercially. 

The same commercial Bi—Mo—P—O catalyst was used in a study by Van der Wiele [347], which included the oxidation of the xylenes at 400— 500° C. In contrast to the oxidation of toluene, dealkylation cannot be neglected. Table 33 presents an example of the product distribution at a 71—74% conversion level for both the xylenes and toluene. Remarkably, substantial amounts of the dialdehyde are only formed from p-xylene, while an enhanced benzene production is found in the case of o-xylene. The reaction schemes shown on p. 208 are proposed the combustion reactions, applicable to each component in the scheme are left out for simplicity. 

The Pt(CH2 = CH2)(PPh3)2-catalyzed dehydrogenative double silylation of olefins and dienes with o-bis(dimethylsilyl)benzene was also examined by Tanaka and co-workers.61 The major product of the reaction with dienes, such as isoprene and penta-1,2-diene, is a result of 1,2-addition to the less substituted double bond. The reaction pathway for simple alkenes, shown in Eq. (19), appears to be dependent on the alkene substrate and, in some cases, on reaction temperature. Products resulting from 1,2-addition, 1, and 1,1-addition, 2, are detected for various substrates. In addition, hydrosilylation may occur to give the simple hydrosilylated product, 3, or a by-product, 4, derived from 1,4-migration of a methyl group in 3. 

There was always an induction period of 10 to 20 min before the benzene product reached its steady-state rate of production as detected by the mass spectrometer after the introduction of cyclohexane onto the crystal surface. This is shown in Fig. 22 for several catalyst temperatures. The catalyst was initially at 300 K. When steady-state reaction rates were obtained, the catalyst temperature was rapidly increased (in approximately 30 sec) to 423 K and the reaction rate monitored. This was repeated with heating to 573 and 723 K. The benzene desorbed during rapid heating of the catalyst surface is approximately 1 x 1013 molecules or less and represents only a small fraction of the carbon on the surface. The steady-state reaction rates at a given temperature are the same whether the catalyst was initially at that temperature or another. This induction period coincides with a higher than steady-state uptake of cyclohexane. A mass balance calculation on carbon, utilizing the known... 

The rate of benzene production from neat benzaldehyde solution was measured as a function of [Rh(dppp)2]+ concentration at 135°C. The reaction is first order in catalyst concentration as shown in Figure 1 (21). The rate of benzene production also was monitored as a function... 

The use of photochemical dinitrogen loss has been selectively employed in similar reactions with some notably enlightening results [124,125]. An early study shows that Cp Re(CO)(L)(N2) (L is P(OEt)3, P(OMe)3, PMe2Ph) photochemically produces frans-Cp Re(CO)(L)(Ph)Cl under UV irradiation in chlorobenzene, similar to the reports above [124]. However, the analogous reaction of Cp Re(CO)2(N2) with 1,4-difluorobenzene, produces both the C-H oxidative addition product Cp/Re(CO)2(Ar)H (Ar is 2,5-C6F2H3) and the coordinated benzene product, Cp Re(CO)2( 2-l,4-C6F2H4) [125]. The two isomers interconvert around 213 K. 

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