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Alkylation of isobutane

Faujasites of the X and Y type are the most frequently studied zeolite structure type for this reachon. Because the key step in the reachon is a hydride hansfer, zeolites with low Si02/Al203 ratios are favored. The other preferred characteristic is a large pore opening and hence a low diffusion barrier to product diffusion. These details and others were reviewed recently by Feller et al. [50] (Table 12.8). [Pg.364]


Alkylation of isoalkanes with alkenes is of particular significance. The industrially used alkylation of isobutane with isobutylene to iso-... [Pg.164]

Products do not contain 2,2,3-trimethylbutane or 2,2,3,3-tetramethylbutane, which would be expected as the primary alkylation products of direct alkylation of isobutane with propylene and isobutylene, respectively. In fact, the process iavolves alkylation of the alkenes by the carbocations produced from the isoalkanes via intermolecular hydride abstraction. [Pg.556]

The catalysts used in the industrial alkylation processes are strong Hquid acids, either sulfuric acid [7664-93-9] (H2SO or hydrofluoric acid [7664-39-3] (HE). Other strong acids have been shown to be capable of alkylation in the laboratory but have not been used commercially. Aluminum chloride [7446-70-0] (AlCl ) is suitable for the alkylation of isobutane with ethylene (12). Super acids, such as trifluoromethanesulfonic acid [1493-13-6] also produce alkylate (13). SoHd strong acid catalysts, such as Y-type zeoHte or BE -promoted acidic ion-exchange resin, have also been investigated (14—16). [Pg.45]

The value of butylenes ia the United States is determined by their value ia alkylation of isobutane to high octane gasoline. Table 11 shows how the chemical use of ethylene, propylene, butylenes, and butanes varied between 1983 and 1988 and their corresponding price swiags. [Pg.371]

Alkylation of isobutane and ethylene with a complex of hquid hydrocarbon -1- AICI3 -1- HCl. [Pg.2092]

Figure 9.14. Alkylation of isobutane and propene is a chain reaction with the isobutene carbenium ion as the chain carrier (indicated... Figure 9.14. Alkylation of isobutane and propene is a chain reaction with the isobutene carbenium ion as the chain carrier (indicated...
This contribution is an in-depth review of chemical and technological aspects of the alkylation of isobutane with lightalkenes, focused on the mechanisms operative with both liquid and solid acid catalysts. The differences in importance of the individual mechanistic steps are discussed in terms of the physical-chemical properties of specific catalysts. The impact of important process parameters on alkylation performance is deduced from the mechanism. The established industrial processes based on the application of liquid acids and recent process developments involving solid acid catalysts are described briefly. 2004 Elsevier Inc. [Pg.252]

Alkylation of isobutane with C3-C5 alkenes in the presence of strong acids leads to the formation of complex mixtures of branched alkanes, called alkylate, which are excellent blending components for gasoline. Alkylate has a high octane... [Pg.252]

Nivarthy, G.S., Feller, A., Seshan, K., Lercher, J.A., Alkylation of isobutane with light olefins catalyzed by zeolite beta, Microporous Mesoporous Mater., 2000, 75, 35-36. [Pg.145]

FIGURE 6.7. Catalytic conversion of 1-butene in the alkylation of isobutane with 1-butene (at a mol ratio of 12 1) versus reaction time over various catalysts (1 g each) JML-I50 (A) JML-I50 regenerated five times by calcination and sulphation (B) SZ(C) SZ/Si02 (Zr/Si = 50/100, mol/mol) (D) zeolite Beta (Si02/Al203 = 40) (E) zeolite ZSM-5 (Si02/Al203 = 40) (F). [Pg.80]

A. Corma, A. Martinez, and C. Martinez, Influence of process variables on the continuous alkylation of isobutane with 2-butene on superacid sulfated zirconia catalysts, J. Catal. 149, 52-60 (1994). [Pg.90]

TABLE 13.1 Alkylation of Isobutane with 2-Butenes on HF or H2SO4... [Pg.256]

A clear example of the possible use of acid and/or superacid solids as catalysts is the alkylation of isobutane with butenes. Isobutane alkylation with low-molecular-weight olefins is one of the most important refining process for the production of high-octane number (RON and MON), low red vapor pressure (RVP) gasoline. Currently, the reaction is carried out using H2SO4 or HF (Table 13.1), although several catalytic systems have been studied in the last few years. [Pg.257]

A. Mantilla-Ramirez, G. Ferrat-Torres, J.M. Dominguez, C. Aldana-Rivero, and M. Bernal. Influence of reaction parameters and comparison of fluorinated alumina and silica supports in the heterogeneous alkylation of isobutane with olefins. Appl. Cat. A, 143 203-214, 1996. [Pg.52]

The ability of zeolites to catalyze paraffin-olefin alkylation has been known since 1968. Garwood and Venuto of Mobil described the use of rare-earth hydrogen X faujasite for the alkylation of isobutane with ethylene to give branched Cg-Cg... [Pg.509]

Feller, A., Zuazo, L, Guzman, A., Barth, J.-O., and Lercher, J.A. (2003) Gommon mechanistic aspects of liquid and solid acid catalyzed alkylation of isobutane with n-butene./. Catal., 216, 313-323. [Pg.529]

MRSTIK, SMITH, AND PINKERTON—COMMERCIAL ALKYLATION OF ISOBUTANE... [Pg.101]

In the alkylation of isobutane with butenes, several variables have an important bearing on the quality of the alkylate produced. The most important is the concentration of isobutane in the reactor. Although theoretically only equimolecular ratios of isobutane and butene are required for the reaction, a large excess of isobutane in the reaction zone has been found necessary to suppress undesirable side reactions which result in loss of yield and octane number. Over-all isobutane-olefin ratios of 5 to 1 or higher are necessary for the production of high quality aviation alkylate. [Pg.102]

Schematic sketches of four types of reactor systems commonly used for the commercial alkylation of isobutane are shown in Figures 3, 4, 5, and 6. Schematic sketches of four types of reactor systems commonly used for the commercial alkylation of isobutane are shown in Figures 3, 4, 5, and 6.
Successful catalytic alkylation of isobutane with ethylene has been accomplished in one commercial installation using aluminum chloride catalyst (I). The chief product of the reaction is 2,3-dime thy lbutane, a hydrocarbon having very high aviation octane ratings. Ethylene has also been alkylated with isobutane in a thermal process to give 2,2-dimethylbutane as the chief product component (6). When sulfuric or hydrofluoric acid alkylation with ethylene is attempted, the ethylene forms a strong bond with the acid, and fails to react with isobutane. The net result is the formation of little or no product, accompanied by excessive catalyst deterioration. [Pg.108]

For purposes of plant design and for optimum operation consistent with feed stock availability, it is necessary to be able to predict accurately the octanes of the alkylate produced under varying operating conditions. Such a correlation developed from several hundred pilot plant and commercial plant tests is presented in Figures 7, 8, and 9. This correlation is applicable to sulfuric acid alkylation of isobutane with the indicated olefins, and was developed specifically for the impeller-type reaction system, although it also appears to be satisfactory for use with some other types of reactors. [Pg.108]

The main products formed by the catalytic alkylation of isobutane with ethylene (HC1—AICI3, 25-35°C) are 2,3-dimethylbutane and 2-methylpentane with smaller amounts of ethane and trimethylpentanes.13 Alkylation of isobutane with propylene (HC1—AICI3, — 30°C) yields 2,3- and 2,4-dimethylpentane as the main products and propane and trimethylpentanes as byproducts.14 This is in sharp contrast with product distributions of thermal alkylation that gives mainly 2,2-dimethylbutane (alkylation with ethylene)15 and 2,2-dimethylpentane (alkylation with propylene).16... [Pg.216]

Table 5.1. Product composition (wt%) in the alkylation of isobutane with C4 alkenes... Table 5.1. Product composition (wt%) in the alkylation of isobutane with C4 alkenes...
Besides the rearrangement of carbocations resulting in the formation of isomeric alkylated products, alkylation is accompanied by numerous other side reactions. Often the alkene itself undergoes isomerization prior to participating in alkylation and hence, yields unexpected isomeric alkanes. The similarity of product distributions in the alkylation of isobutane with n-butenes in the presence of either sulfuric acid or hydrogen fluoride is explained by a fast preequilibration of n-butenes. Alkyl esters (or fluorides) may be formed under conditions unfavorable for the hydride transfer between the protonated alkene and the isoalkane. [Pg.220]

Formation of C8 alkanes in the alkylation of isobutane even when it reacts with propene or pentenes is explained by the ready formation of isobutylene in the systems (by olefin oligomerization-cleavage reaction) (Scheme 5.2). Hydrogen transfer converting an alkane to an alkene is also a side reaction of acid-catalyzed alkylations. Isobutylene thus formed may participate in alkylation Cg alkanes, therefore, are formed via the isobutylene-isobutane alkylation. [Pg.220]

Particularly revealing is the alkylation of isobutane with ferf-butyl cation.35 The product showed, inter alia, the presence of 2,2,3,3-tetramethylbutane (although in low 2% yield). Thus, despite unfavorable steric hindrance in the tertiary-tertiary... [Pg.223]


See other pages where Alkylation of isobutane is mentioned: [Pg.2092]    [Pg.17]    [Pg.298]    [Pg.75]    [Pg.38]    [Pg.52]    [Pg.364]    [Pg.364]    [Pg.368]    [Pg.430]    [Pg.510]    [Pg.187]    [Pg.226]    [Pg.173]    [Pg.99]    [Pg.99]    [Pg.101]    [Pg.192]    [Pg.216]   
See also in sourсe #XX -- [ Pg.236 ]




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