O-ETHYLTOLUENE

Ethyltoluene is manufactured by aluminum chloride-cataly2ed alkylation similar to that used for ethylbenzene production. All three isomers are formed. A typical analysis of the reactor effluent is shown in Table 9. After the unconverted toluene and light by-products are removed, the mixture of ethyltoluene isomers and polyethyltoluenes is fractionated to recover the meta and para isomers (bp 161.3 and 162.0°C, respectively) as the overhead product, which typically contains 0.2% or less ortho isomer (bp 165.1°C). This isomer separation is difficult but essential because (9-ethyltoluene undergoes ring closure to form indan and indene in the subsequent dehydrogenation process. These compounds are even more difficult to remove from vinyltoluene, and their presence in the monomer results in inferior polymers. The o-ethyltoluene and polyethyltoluenes are recovered and recycled to the reactor for isomerization and transalkylation to produce more ethyltoluenes. Fina uses a zeoHte-catalyzed vapor-phase alkylation process to produce ethyltoluenes. 

The pathways for the degradation of toluene and xylene under denitrifying and sulfate-reducing conditions have been studied most extensively, and they take place by reactions quite different from those used by aerobic bacteria. As an example, two anaerobes affiliated with known sulfate-reducing bacteria isolated from enrichments with crude oil were able to grow at the expense of a number of alkylated benzenes—strain oXySl with toluene, o-xylene, and o-ethyltoluene and strain mXySl with toluene, m-xylene, and m-ethyltoluene (Harms et al. 1999). 

Common Name 1-Ethyl-2-methylbenzene Synonym 2-ethyltoluene, o-ethyltoluene... 

Reported vapor pressures of o-ethyltoluene at various temperatures and the coefficients for the vapor pressure equations... 

FIGURE 3.1.1.12.1 Logarithm of vapor pressure versus reciprocal temperature for 1-ethyl-2-methylbenzene (o-ethyltoluene). 

Ethyl terl-butyl ether (ETBE), 10 548, 574, 576 12 404-405 derivation from ethanol, 10 557 Ethyltoluene, 23 329, 349 o-Ethyltoluene, 23 349 p-Ethyltoluene, 10 597 p-Ethyltoluene precursor, synthesis of, 23 351 p-Ethyltoluene synthesis, molecular sieves in, 16 846... 

Szebenyi et al. 76) reacted -nonane over alumina-supported Pt and Pt-Re catalysts. With increasing temperature (i.e., less surface hydrogen present) the o-ethyltoluene/ -propylbenzene ratio increased ... 

The microreaction system and operation were described previously (2). Reactions of 5 jul pulses of o-ethyltoluene (280 ml (NTP)/min He passing over 0.057 gram catalyst) were measured in the catalyst initial activity region prior to extensive deactivation. Catalysts were pretreated for 15.5 hours at 538°C in 40 ml (NTP)/min He. 

Selectivity as a Function of Alumina Content. At a reaction temperatures of 204° and 343°C, Csicsery (7, 8) found that the major reaction of o-ethyltoluene over H-mordenite was isomerization to the m- and p-isomers. Results of our study, listed in Table I and plotted in Figure 7, show that this is also so at 360°C. Isomers are the major reaction products over both the parent H-mordenite at 360°C and aluminum-deficient H-mordenite at 360°-505°C. At the higher temperatures, H-mordenite cracking selectivity becomes predominant. 

Table I. Composition of Aromatics After Reaction of o-Ethyltoluene over H-Mordenites at 360°Ca...

To examine selectivity relationships, the following classification of o-ethyltoluene products is proposed for simplification ethylbenzene, toluene, and benzene are dealkylation products p- and m-ethyltoluene are isomerization products. Formation of m- and p-xylenes must have involved skeletal rearrangements to have been produced from o-ethyltoluene. Accordingly, these compounds are counted as isomerization products. In all cases studied, toluene was the major dealkylation product, and m- and... 

Figure 7. Selectivity at initial activity of reaction products of o-ethyltoluene using H-mordenites...

To explain the observed selectivity effect, consider the type of mechanism proposed by Matsumoto et al (9, 10) for reactions of o-ethyltoluene with H+A102 of amorphous silica-alumina cracking catalysts. 

The compound in part b is 1,3,5-trimethylbenzene and that in part c is o-ethyltoluene or 2-ethyltoluene. 

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