Toluene, reaction with hydrogen

Cg Aromatic Reactions with Hydrogen. The mild acid nature of the family of aluminophosphate based sieves renders them selective for a number of rearrangements as observed in the reactions of olefins and paraffins described above. This property as well as their apparent low disproportionation activity observed in the alkylation of toluene suggests that they be evaluated as the acid function in bifunctional Cg aromatic isomerization. As described above, cyclo-olefins are most likely involved in the conversion of ethylbenzene to xylenes. Strong acid functions, such as in mordenite, actively isomerize cyclo-olefinic intermediates but also catalyze ring-opening reactions which lead to loss of aromatics. A more selective acid function must still effectively interconvert ethyl cyclohexene to dimethylcyclohexenes but must leave the cyclohexene rings intact. 

Hydrodealkylation of toluene is a process where toluene is converted into benzene by reaction with hydrogen, forming Diphenyl as a byproduct. This is a well known process, which has been studied in numerous publications. The reference design and flowsheet considered in this paper are taken from Seider et al. (1999), where further details can be found. The necessary steady state simulations have been performed with a commercial process simulator, from where the results have been transferred to a software developed for this work to calculate the indicator values. The steady state simulation results are also transferred to ICAS (ICAS Documentation, 2002) to determine the environmental impact factors, the sustainability metrics and the safety factors. Table 1 shows the most important indicator-values from the base case design. A detailed calculation results document can be obtained from the corresponding author. 

Ketones can be converted into homologous nitriles either by reaction of the corresponding toluene-/ -suIphonylhydrazone with hydrogen cyanide followed by pyrolysis (Scheme 62), or, at least in the case of adamantanone,... 

Arata and Hino found that better catalysts could be obtained by calcining Fe(OH)3 at 573 — 873 K. The hydroxide was prepared by hydrolyzing FeCls or Fe(N03)3 9H20. The alkylation reactions were carried out at room temperature with 50 cm of toluene solution (0.5 mol 1 ) of benzyl chloride, t-butyl chloride or acetyl chloride and 0.1 g (for benzylation or t-butylation) or 0.5g (for acetylation) of catalyst. Benzylation and t-butylation was completed within 2 min and 10 min, respectively. For acetylation with acetyl chloride, the reaction was slow, the conversion being 28% after 6 h of reaction. The reaction with acetyl bromide is slighdy faster conversion of 30% was obtained after 4 h.The isomer distribution of alkyltoluenes was 42% ortho, 6% meta and 52% para for benzylation and 3% meta and 97% para for butylation with /-butyl chloride. It was presumed that iron chloride formed on the surface of amorphous iron oxide by its reaction with hydrogen chloride is a catalytically active species for alkylation. 

These effects can be attributed mainly to the inductive nature of the chlorine atoms, which reduces the electron density at position 4 and increases polarization of the 3,4-double bond. The dual reactivity of the chloropteridines has been further confirmed by the preparation of new adducts and substitution products. The addition reaction competes successfully, in a preparative sense, with the substitution reaction, if the latter is slowed down by a low temperature and a non-polar solvent. Compounds (12) and (13) react with dry ammonia in benzene at 5 °C to yield the 3,4-adducts (IS), which were shown by IR spectroscopy to contain little or none of the corresponding substitution product. The adducts decompose slowly in air and almost instantaneously in water or ethanol to give the original chloropteridine and ammonia. Certain other amines behave similarly, forming adducts which can be stored for a few days at -20 °C. Treatment of (12) and (13) in acetone with hydrogen sulfide or toluene-a-thiol gives adducts of the same type. 

The aromatic sulfonyl chlorides which have no a-hydrogen and thus cannot form sulfenes give acylic sulfones. Thus 1-piperidinopropene on reaction with benzene sulfonyl chloride (9J) gave 2-benzenesulfonyl-l-piperidinopropene (153). Similarly the enamine (28) reacts with p-toluene-sulfonyl chloride to give the 2-p-toluenesulfonylcyclohexanone (154) on hydrolysis (/OS). 

The catalytic disproportionation of toluene (Figure 10-13) in the presence of hydrogen produces henzene and a xylene mixture. Disproportionation is an equilihrium reaction with a 58% conversion per pass theoretically possible. The reverse reaction is the transalkylation of xylenes with henzene ... 

It follows from the above that, in the reactions of fairly unreactive aromatics, the formation of Cl+ (either from HOC1 or H2OCl+) will be relatively fast compared with the subsequent reaction of this ion with the aromatic so that the kinetics will be governed mainly by the third term in equation (94). Hence de la Mare et al.204 found the rate of chlorination of benzene and toluene by acidified hypochlorous acid to depend on the concentration and nature of the aromatic and to increase with hydrogen ion concentration though (as in the case of positive... 

Anon., Univ. Safety Assoc., Safety Newsletter, 1982-1984 A solution of the chloride (120 ml) in toluene (750 ml) was treated (apparently without effective stirring) with excess sodium bicarbonate solution to destroy it. When reaction had ceased, the organic layer was poured into a waste solvent drum. Vigorous evolution of sulfur dioxide and hydrogen chloride then ensued from reaction with ethanol (toluene-soluble) in the waste drum. For destruction of solutions of sulfinyl chloride in water-insoluble solvents, extremely good agitation is necessary to ensure proper contact with a basic reagent. Ammonia is more soluble in toluene than is water, so ammonia solution should be used after bicarbonate treatment to ensure complete destruction. 

The fused heterocycles 58 have been synthesized via cycloaddition of 1-phenylisobenzofuran 467 (prepared in situ from 466) and methyl a-phenylselenoacrylate. The cycloaddition was carried out in toluene at 80 °C for 2 h to give adduct 468. Hydrogen peroxide on reaction with 468 at —40 °C provided product 469. The [3+2] cycloaddition between 469 and an amine-derived dipole has been accomplished under acidic conditions <1985CPB2762> to provide the heterocycle 58 as a single diastereomer (Scheme 105) <20000L923>. 

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