Benzene toluene conversion

The liquid stream can readily be separated into relatively pure components by distillation, the benzene taken off as product, diphenyl as an unwanted byproduct and the toluene recycled. It is possible to recycle the diphenyl to improve selectivity, but it will be assumed that is not done here. The hydrogen feed contains methane as an impurity at a mole fraction of 0.05. The production rate of benzene required is 265 kmol-lr1. Assume initially that a phase split can separate the reactor effluent into a vapor stream containing only hydrogen and methane, and a liquid containing only benzene, toluene and diphenyl, and that it can be separated to produce essentially pure products. For a conversion in the reactor of 0.75,... 

Toluene alkylation with isopropyl alcohol was chosen as the test reaction as we can follow in a detail the effect of zeolite structural parameters on the toluene conversion, selectivity to cymenes, selectivity to para-cymene, and isopropyl/n-propyl ratio. It should be stressed that toluene/isopropyl alcohol molar ratio used in the feed was 9.6, which indicates the theoretical toluene conversion around 10.4 %. As you can see from Fig. 2 conversion of toluene over SSZ-33 after 15 min of T-O-S is 21 %, which is almost two times higher than the theoretical toluene conversion for alkylation reaction. The value of toluene conversion over SSZ-33 is influenced by a high rate of toluene disproportionation. About 50 % of toluene converted is transformed into benzene and xylenes. Toluene conversion over zeolites Beta and SSZ-35 is around 12 %, which is due to a much smaller contribution of toluene disproportionation to the overall toluene conversion. A slight increase in toluene conversion over ZSM-5 zeolite is connected with the fact that desorption and transport of products in toluene alkylation with isopropyl alcohol is the rate controlling step of this reaction [9]... 

The pyrolysis gas chromatogram of ABS at 550°C changes considerably when the pyrolysis products are passed over zeolite catalysts. The specific activity towards certain reactions, e.g., cycliza-tion, aromatization, or chain cleavage is somewhat dependent on the nature of the individual zeolite. In general, enhanced benzene, toluene, ethylbenzene at the cost of dimer, trimer formation is observed. Nitrogen containing compounds do not appear in the pyrolysis oil after catalytic conversion. However, the product gas is rich in nitriles (132). 

Crude oil, however, has almost completely replaced coal as a source of aromatics. Crude oil contains several percents of benzene, toluene, and xylenes and their cycloalkane precursors. The conversion efficiency for preparing toluene or xylenes from their precursors is nearly 100%. For benzene this efficiency is slightly lower. Moreover, alkanes are also transformed to aromatics during refining processes, allowing efficient production of simple aromatic compounds. 

The hydrogen polysulphides arc miscible with benzene, toluene, chloroform, bromofomi, carbon disulphide, ether and heptane, giving relatively stable solutions,5 and the use of such solutions has been suggested in place of sulphur chloride for the vulcanisation of caoutchouc at the ordinary temperature. The addition of alcohol to the benzene solutions induces rapid decomposition, with formation of nacreous sulphur, which slowly undergoes conversion into ordinary sulphur (p. 25). Ketones, nitrobenzene, aniline and pyridine also catalyse the decomposition. 

Sarca and Laali199 have used triflic acid in butylmethylimidazolium hexafluor-ophosphate BMIM][PF6 ionic liquid for the benzylation of various arenes with benzyl alcohol [Eq. (5.76)]. When compared with Yb(OTf)3, triflic acid proved to be a better catalyst showing higher selectivity (less dibenzyl ether byproduct) by exhibiting similar activity (typically complete conversion). Of the isomeric products, para isomers dominate. Experimental observations indicate that dibenzyl ether originates from less complete protonation of benzyl alcohol and, consequently, serves as a competing nucleophile. Both substrate selectivity (kT/kB) and positional selectivity (ortho/para ratio) found in competitive benzylation with a benzene-toluene mixture (1 1 molar ratio) are similar to those determined in earlier studies, indicating that the nature of the electrophile is not affected in the ionic liquid. 

Another process is the conversion of toluene into caprolactam that provides an alternative basic building block for this chemical other than benzene. Toluene is oxidized to benzoic acid, and hydrogenation to cyclohexanecar-boxylic acid is followed by treatment with nitrosylsulfuric acid to form cyclohexanone oxime followed by rearrangement to caprolactam. 

Conversely, nucleophilic molecules (Nu) [Lewis bases e.g., catechols, hy-droquinones, phenols, alcohols, and thiols (and their anions) aromatic hydrocarbons and amines (benzene, toluene, pyridine, bipyridine)] can be oxidized by (1) direct electron-transfer oxidation [Eq. (12.3)] or (2) by coupling with the oxidation product of H20 (or HO-), hydroxyl radical (HO-) [Eq. (12-4)] ... 

The alkylation reactions of toluene and benzene with dodecene were used as test reactions in order to evaluate the catalyst activity. It could be observed that the IL is catalytically activity after being immobilised. Moreover, due to the better dispersion of the solid catalyst in the reaction media, even the conversions obtained for the supported IL were better than for the pure IL. In the alkylation of toluene conversions reached at standard conditions were twice as high for the immobilised ILs, for benzene the difference was even bigger. 

In the latter part of the nineteenth century new raw materials for the chemical industries became available from city gas and by-product cote oven operations. Benzene, toluene, xylene, naphthalene, phenol, cresols, and xylenols served as crudes for conversion to various intermediates used in the growing new synthetic dyestuff industry. Many of these intermediates and finished products were nitro compounds and found their way into the explosive industry. 

Application Increase the value of steam cracker pyrolysis gasoline (py-gas) using conversion, distillation and selective hydrogenation processes. Pygas, the C5-C9 fraction issuing from steam crackers, is a potential source of products such as dicyclopentadiene (DCPD), isoprene, cyclopentane, benzene, toluene and xylenes. 

The differences in liquid product composition from the two types of processes are even more pronounced. The major liquid products (see Table V) from hydropyrolysis of 2 at 550°C are C6-Ci0 cyclohexenes and cyclohexanes, and C5-C8 open-chain hydrocarbons, while in thermal cracking the main liquid product at this temperature is 1,2,3,4,5,6,7,8-octahydronaphthalene. At 600°C a much higher conversion of 2 into C5—C10 aliphatic products is observed in the hydropyrolysis Experiment 25, whereas in the thermal cracking Experiment 26 there is much higher formation of aromatic products, i.e., benzene, toluene, ethylbenzene, and... 

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