Alkylation toluene with ethylene

The same type catalyst modified with boron (41), magnesium (42), or phosphoms (43) to reduce the pore size can be used to alkylate toluene with ethylene to produce predominantly -ethyltoluene. Since -ethyltoluene [622-96-8] has the smallest effective diameter of the ethyltoluene isomers, the selectivity to this isomer is favored because it can most easily escape the ZSM-5 pore stmcture. For the same reason, the alkylation of toluene [108-88-3] to xylene [106 2-3] also is favored over the usual acid catalyzed equiHbrium mixture of isomers when it is carried out over magnesium- or phosphoms-modified ZSM-5 (44). 

The reaction of toluene with propylene and higher olefins is similar to that of toluene with ethylene. In contrast to the acid-catalyzed alkylation of aromatics, the base-catalyzed reaction of toluene with propylene takes place less rapidly than the reaction with ethylene. With more severe conditions, such as temperatures of 225-250°, the reaction of toluene with propylene may be made to proceed satisfactorily, but butylenes yield only small amounts of products even at 300°, as reported by Pines and Mark 20). Such conditions result not only in more hydrogen transfer, but alkyl-group... 

A material such as Na°/NaY catalyzes the aldol condensation of acetone, to form mesityl oxide and eventually isophorone. Another strong base catalyzed reaction is the side chain alkylation of toluene with ethylene. In contrast with acid catalysis, side chain reaction is strongly preferred over ring alkylation. With a Na°/NaX in the gas phase at 473 K, toluene reacts to give n-propylbenzene (66%) and the dialkylated product, 3-phenylpentane (32%) (41). 

Of the processes likely to favor its production, only the one proposed by Mobil currently appears capable of industrialization. This is because, among the different forms of zeolite developed by this company, tbe catalyst HZSM5, modified by magnesium mid phosphorus, is capable of alkylating toluene by ethylene with a high para isomer selectivity. Thus, a 95/5 blend of p- and m>methylethylbenzenes can be obtained, which considerably simplifies separation problems and yields p-meth styrene by dehydrogena ... 

Alkylation of toluene with ethylene over W modified ZSM-5 at 620 K and WHSV = 10 h l,... 

The present study explores acidity and poisoning on the external surface of a zeolite, using ZSM-5 and a facile probe reaction, the alkylation of toluene with ethylene to yield ortho-, meta- and para-ethyltoluenes (OET, MET and PET, respectively) (ref. 3). As with the xylenes, strong para-selectivity is to be expected in the toluene-ethylene reactions which occur within the ZSM-5 poiespace. 

This paper deals with the activity and para-selectivity of small crystals of H-ZSM-5 zeolites modified by various metal cations located at different sites. The effect of Fe, Mn (which can be expected to enhance coke removal) and Al cations, modelling an electron acceptor site without redox properties, located mostly in the zeolite channels or on the zeolite outer surface, has been investigated. Attention has been paid to the alkylation of toluene with ethylene, including coke formation and its removal by oxidation. The surface deposition of silicon is discussed to explain some effects of the metal cation location in the zeolite on its para-selectivity. 

The surface silylated zeolites were prepared by suspending the H-ZSM-5 or FeH-ZSM-5 zeolite in n-hexane into which a calculated amount of tetraethyl orthosilicate was added to obtain addition of 1.5 wt. % of Si in the final product (abbrev. SiH-ZSM-5 or SiFeH-ZSM-5). n-Hexane was evaporated and the zeolites were dried and calcined in an oxygen stream at 770 K for 5 hours. To add some Fe cations to the surface of silylated zeolites, the SiH-ZSM-5 was introduced into a FeCl solution, filtered and dried (abbrev. FeSiH-ZSM-5). The characteristics of the parent and modified zeolites are given in the Table. The alkylation of toluene with ethylene was carried out in a vapour phase continuous flow microreactor at atmospheric pressure. Nitrogen as a carrier gas was saturated with toluene to 18.5 vol. %, the toluene to ethylene molar ratio was 3.8. The reaction products were analyzed by an "on-line" gas chromatograph (Hewlett-Packard 5890) with MS and FID detection. 

Fig. 1 Alkylation of toluene with ethylene at WHSV 10 h , 620 K, after 15 minutes in T-O-S on ZSM-5 zeolites. A) Dependence of toluene conversion and p-ET selectivity on the number of strong acid OH groups, B) Dependence of p-ET selectivity on toluene conversion H-(0, ), MnH-(Q,B), FeH-(A,4), AlH-(y, ),...

The presence of isolated metal cations in the zeolite channels also plays an important role in the oxidation of coke formed during the alkylation of toluene with ethylene. The facility of coke burning was characterized by the initial temperature at which the coke started to be removed as CO and CO and the temperature for the CO and CO2 concentration maxima. It appears that Mn and especially Fe cations enhance significantly coke burning. The initial temperature for coke oxidation and the concentration maxima for CO and CO evolution were 470, 590 and 780 K, resp., for FeH-ZSM-5 and 520, 765 and 830 K, resp., for pure H-ZSM-5. On the other hand, A1 cations apparently slightly retard coke oxidation (CO is evolved at higher temperatures) likely owing to steric hindrances. 

Another example of product selectivity is the alkylation of toluene with ethylene to give ethyltoluene (Table 7-5). The comparison with the conventional Friedel-Crafts catalyst shows the clear advantages of the highly selective zeohte catalyst... 

Para-methyl-styrene can substitute styrene in several applications (210). This is produced by alkylation of toluene with ethylene over a chemically modified ZSM-5. This catalyst gives high selectivity to the para isomer. 

Kaeding, W.W., Brewster Young, L. and Chin-Chiun Chu (1984) Shape-selective reactions with zeolite catalysts. IV- Alkylation of toluene with ethylene to produce p-ethyltoluene J. Catal. 89, 267-273. 

Sequencing of two distillation columns. The demand for styrene monomer continues to increase. Other companies produce styrene by alkylating benzene with ethylene to ethylbenzene, fol-bwed by dehydrogenation to styrene. Our chemists have developed a new reaction path to styrene that involves other chemicals that appear to be available from our own supplies at a relatively low cost. These chemicals are toluene and methanol. We have been asked to prepare a preliminary design and economic evaluation for this new route to determine if it merits further consideration. If so, we will consider entering the styrene manufacturing business. 

The demand for vinyltoluene is considerably higher than that for divinylbenzene, reaching around 30,000 to 35,000 tpa. Ethyltoluene is used as a raw material. It is produced by Friedel-Crafts alkylation of toluene with ethylene in the presence of AICI3 at 80 °C in the liquid phase, or in the gas phase, using zeolite catalysts. During the refining operation, care must be taken to ensure that the o-ethyl-... 

Modified Zeolites. As described above, alkali ion-exchanged zeolites are weak bases. Various efforts have been made to increase the base strength of alkali metal-ion exchanged zeolites. Metallic sodium particles in zeolites are formed by the decomposition of occluded sodium azide (59). These sodium particles are capable of performing base-catalyzed reactions. These catalysts catalyze the isomerization of butenes at 300 K and the side-chain alkylation of toluene with ethylene at 523 K. 

Mobil PMS is prepared by an acid-catalyzed alkylation of toluene with ethylene to make ethyltoluene, which is subsequently dehydrogenated to methylstyrene. The key technological innovation which makes Mobil PMS different from vlnyltoluene is the ability to produce the para Isomer in high selectivity (> 97%) during the ... 

Alkylation of Toluene with Ethylene Composition of Typical Product Streams... 

While alkylation of aromatics with olefins or alcohols occurs at the aromatic ring over acid catalysts, alkylation of the alkyl groups proceeds over basic catalysts. Pines and coworkers reported that the side-chain alkylation of toluene with ethylene is effectively catalyzed by the use of a mixture of sodium and a promotor such as anthracene or o-chlorotoluene. ... 

The reactions of xylenes and ethylbenzene with methanol over RbX also give side-chain alkylation products. Alkylation of toluene with ethylene over RbX gives isopropylbenzene and a-methylstyrene. Similarly, the reactions of a- and jS-methylnaphthalene with methanol give the corresponding ethylnaphtalenes with traces of vinylnaphthalenes over KX and RbX at 670 — 720 K. ... 

HZSM-5 modified by tetraethyl orthosiUcate was used for alkylation of toluene with ethylene in supercritical carbon dioxide [194]. The maximum yield and selectivity of p-ethyltoluene were 70 and 97%, respectively, at 623 K, 13.1 MPa, Wf/5V=5.0h and a molar ratio of toluene to ethylene of 5. 

As the isomerization reaction among three kinds of methyl ethylbenzene isomers (K3, K4) is much easier than alkylation reaction of toluene with ethylene (Kl, K2), shown in Figure 1, the mixture of / ara-methyl ethylbenzene, orth-vasOsy ethylbenzene... 

According to the results shown in Table 1, zeolite ZSM-5, with the high Si/Al ratio 150, 10-membered ring channels and mid-strength acidity, shows both high selectivity and catalytic activity for alkylation of toluene with ethylene. 

A modified ZSM-5 catalyst has a unique shape-selective property for producing -ethyltoluene [622-96-8] selectively by the alkylation of toluene [108-88-3] with ethylene (54). j )-Ethyltoluene is an intermediate in the production of poly -methylstyrene) [24936-41-2] (PPMS), which is reported to have... 

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