Toluene ethylene alkylation

In the presence of alkah metals such as potassium and sodium, toluene is alkylated with ethylene on the methyl group to yield, successively, normal propylbenzene, 3-phenylpentane, and S-ethji-S-phenylpentane (21). 

Vinyltoluene. Viayltoluene is produced by Dow Chemical Company and is used as a resia modifier ia unsaturated polyester resias. Its manufacture is similar to that of styrene toluene is alkylated with ethylene, and the resulting ethyltoluene is dehydrogenated to yield vinyltoluene. Annual production is ia the range of 18,000—23,000 t/yr requiring 20,000—25,000 t (6-7.5 x 10 gal) of toluene. 

Benzene and para-xylene are the most sought after components from reformate and pygas, followed by ortho-xylene and meta-xylene. While there is petrochemical demand for toluene and ethylbenzene, the consumption of these carmot be discussed in the same way as the other four. Toluene is used in such a large quantity in gasoline blending that its demand as a petrochemical pales in comparison. Fthylbenzene from reformate and pygas is typically dealkylated to make benzene or isomerized to make xylenes. On-purpose production of petrochemical ethylbenzene (via ethylene alkylation of benzene) is primarily for use as an intermediate in the production of another petrochemical, styrene monomer. Ethylbenzene plants are typically built close coupled with styrene plants. 

VinyUoluene. Vinyltolnene is used as a resin modifier in nnsaturated polyester resins. Its manufacture is similar to that of styrene toluene is alkylated with ethylene, and the resulting ethyltoluene is dehydrogenated to yield vinyltoluene. 

Figure 8. Conversion of toluene during alkylation with ethylene over samples activated at 623 K and 773 K, respectively, after 55 min time on stream. T = 620 K, WHSV = 10 h l, T/E ratio = 3.8.

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. 

Tn 1955 Pines and Schaap (1) discovered that toluene was alkylated by ethylene in the presence of sodium or potassium metal or, more specifically, their organometallic derivatives. This reaction requires a high temperature (about 200°C) and considerable olefin pressure the organometallic catalyst is essentially insoluble in the reaction medium. The catalyst cycle—for example, in the side-chain ethylation of toluene— involves a benzyl carbanion which adds to ethylene to form a primary alkyl carbanion. The latter immediately abstracts a proton from the excess toluene reactant to form n-propylbenzene and to reform the energetically-favored benzylic anion in a catalytic cycle. 

Zeolite NU-87, if containing Bronsted-acid sites, is an active catalyst for a large variety of acid catalyzed reactions hke toluene disproportionation, alkylation of benzene with ethylene, amination of methanol to methylamines etc. [51]. Moreover, it was found to possess interesting shape selective properties in the conversion of m-xylene [52] and of polynuclear aromatics, e.g. methylnaphtha-lenes [53]. On non-acidic (i.e. Cs+-exchanged) zeolite NU-87, loaded with small amounts of platinum, n-alkanes like n-hexane or n-octane can be dehydrocycliz-ed in high yields to the corresponding aromatics [54]. 

Certain Mobil ZSM-5 type zeolites have pore openings with rings of 10 oxygen atoms (17). This structure permits access to reactant or product molecules with larger dimensions, such as substituted aromatic compounds, which can diffuse in and out of the catalyst. A mixture of toluene and alkylating agents, such as methanol or ethylene can easily enter the pores and react at an acidic site to produce the corresponding xylenes or ethyltoluenes In previously reported work, thermodynamic equilibrium mixtures of Isomers were produced (18). Furthermore, individual Isomers were Isomerized to the equilibrium mixture under alkylation conditions over a zeolite with similar properties (19). 

PMMA is not affected by most inorganic solutions, mineral oils, animal oils, low concentrations of alcohols paraffins, olefins, amines, alkyl monohahdes and ahphatic hydrocarbons and higher esters, ie, >10 carbon atoms. However, PMMA is attacked by lower esters, eg, ethyl acetate, isopropyl acetate aromatic hydrocarbons, eg, benzene, toluene, xylene phenols, eg, cresol, carboHc acid aryl hahdes, eg, chlorobenzene, bromobenzene ahphatic acids, eg, butyric acid, acetic acid alkyl polyhaHdes, eg, ethylene dichloride, methylene chloride high concentrations of alcohols, eg, methanol, ethanol 2-propanol and high concentrations of alkahes and oxidizing agents. 

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... 

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). 

Polymerization of Ethylene by Zirconium Alkyl Halides in Toluene at 80°C. Concentration 3.00 X 10 3 mole liter-1 Ethylene Partial Pressure 10 atm.Hydrogen Partial Pressure 10 atm (9, 16)... 

Polymerization of Ethylene with Transition Metal Alkyl Compounds in Toluene at 80°C... 

Polymerization of Propylene by Transition Metal Alkyl Compounds Toluene as Solvent, Temperature 65°C. Ethylene Pressure 10 atm (IS, 16)... 

Among the wide variety of organic reactions in which zeolites have been employed as catalysts, may be emphasized the transformations of aromatic hydrocarbons of importance in petrochemistry, and in the synthesis of intermediates for pharmaceutical or fragrance products.5 In particular, Friede 1-Crafts acylation and alkylation over zeolites have been widely used for the synthesis of fine chemicals.6 Insights into the mechanism of aromatic acylation over zeolites have been disclosed.7 The production of ethylbenzene from benzene and ethylene, catalyzed by HZSM-5 zeolite and developed by the Mobil-Badger Company, was the first commercialized industrial process for aromatic alkylation over zeolites.8 Other typical examples of zeolite-mediated Friedel-Crafts reactions are the regioselective formation of p-xylene by alkylation of toluene with methanol over HZSM-5,9 or the regioselective p-acylation of toluene with acetic anhydride over HBEA zeolites.10 In both transformations, the p-isomers are obtained in nearly quantitative yield. 

It has been found that the disproportionation of toluene over ZSM-5 catalyst can be directed such that p-xylene is the predominant xylene isomer (14-17). This reaction, designated STOP, is one of several in which disubstituted aromatics rich in the para isomer are produced. Others are the alkylation of toluene with methanol to produce p-xylene (15,18) and with ethylene to produce p-ethyltoluene (19,20), as well as the aromatization of olefins (20), paraffins (20) and of methanol... 

The pyrolysis of diethyl mercury has been studied using a nitrogen carrier flow system87 both in the presence and absence of toluene. The experimental conditions used were total pressure = 10+1 torr with 0.4 torr partial pressure of toluene, alkyl pressure 1-10 x 10 2 torr, decomposition 10-75 % and contact time 0.1-0.3 sec. The presence of toluene had no effect on the rate coefficient, the observed ethane/ethylene ratio ( 1) or the C4/C2 ratio ( 4). These ratios were essentially independent of temperature. 

Of the olefins, ethylene has been most extensively studied (19, 21, 23-26, 36) it reacts most readily in base-catalyzed alkylations. In general temperatures of 150-200 are used with relatively low ethylene pressures (0-70 atm.). Benzylic hydrogens are replaced by ethyl groups i.e., toluene yields n-propylbenzene. Additional substitution on the a-carbon may yield 3-phenylpentane and 3-ethyl-3-phenylpentane [Reaction (3)]. 

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... 

In this work acidic and catalytic properties of ZSM-5 type zeolites containing polyvalent cations in exchange positions wera Investigated. Toluene alkylation by ethylene and ethylbenzene transalkylation were studied as model reactions. 

Toluene alkylation by ethylene temperature inside catalyst bed... 

Pig. 1 Scheme of main reaction routes of toluene alkylation by ethylene. (ET= ethyltoluene XYL=xylene S = selectivity to the product on converted toluene)... 

---