Mass isobutane alkylation

Such reactions can take place predominantly in either the continuous or disperse phase or in both phases or mainly at the interface. Mutual solubilities, distribution coefficients, and the amount of interfadal surface are factors that determine the overall rate of conversion. Stirred tanks with power inputs of 5-10 HP/1000 gal or extraction-type equipment of various kinds are used to enhance mass transfer. Horizontal TFRs usually are impractical unless sufficiently stable emulsions can be formed, but mixing baffles at intervals are helpful if there are strong reasons for using such equipment. Multistage stirred chambers in a single shell are used for example in butene-isobutane alkylation with sulfuric acid catalyst. Other liquid-liquid processes listed in Table 17.1 are numbers 8, 27, 45, 78, and 90. 

In this work, the goal is to design a control function in such a manner that neither the reaction heat nor kinetic nor mass transfer terms are required for stabilizing temperature. The scheme provides an estimated value of the heat generation from energy balance. Alkylation isobutane/propylene using sulfuric... 

In reviewing the literature one becomes aware that about 12 years ago the petroleum industry was undergoing partial transition into a synthetic chemicals industry and this is reflected in the variety of analyses required. Production of synthetic rubber, 1,3-buta-diene, isobutene, isobutane, styrene, diisobutene, alkylate, iso-octane, copolymer, cumene, and toluene was greatly aided by instrumental analysis including ultraviolet, infrared, mass and emission spectrometry. Without these methods many of the analyses would be entirely impractical because of tediousness, long elapsed time for results, and general expense of operation. 

Intermediates and causes them to abstract hydride Ions more rapidly from Isobutane or any other potential donor. Increased hydride transfer converts more of the carbonlum Ions at the add Interface to saturates faster, yielding product while minimizing polymerization and side reactions. It Is also likely that the surfactants physically block alkyl Ions from one another in the surface film and thus Impede Ion + olefin polymerization. In such a film the carbonlum Ion concentration must also be lower than In the absence of surfactant and mass law effects will therefore also lead to less polymerization and cracking. The fact that steady state hydride transfer rates In H2SO are subject to control through the use of acid modifiers which act In the bulk acid and at the acid-hydrocarbon Interface Is the key to the control of sulfuric acid alkylation. 

Polymer or residue formation is minimized by maintaining proper reaction conditions, i.e., good mass transfer, high isobutane-to-olefin ratio, proper catalyst activity, and minimum concentration of alkylate in the reaction zone. 

Table 12.2 summarizes the key properties of HFand H2SO4. The critical properties for alkylation are acidity and isobutane availability. The catalyst s acidity generally determines the olefin protonation rate. Isobutane availability determines the carbo-cation formation. H2SO4 is a stronger acid than HF. Isobutane is more readily available in HF as it has higher solubility. In addition, isobutane mass transfer from hydrocarbon to acid phase is more expedient in HF versus H2SO4. 

Alkylation of isobutane with ethylene in the presence of zirconium chloride took place at 100 under 15 atmospheres pressure (Ipatieff, 1, p. 682). The product was completely paraffinic and consisted chiefly of hexanes, octanes, and decanes. The catalyst was converted to a dark, pasty mass which was still catalytically active as was shown by its re-use in a second experiment with isobutane and ethylene. 

Reaction pressure was maintained with a dome-loaded back-pressure regulator (Circle Seal Controls). All heated zones were controlled and monitored with a Camile 2500 data acquisition system (Camile Products). Products were analyzed online by gas chromatography with an HP 5890 II GC, equipped with an FID, and a DB-Petro 100 m column (J W Scientific), operated at 35° C for 30 min, ramped at 1.5°/min to 100° C, 5°/min to 250° C for 15 min. An alkylate reference standard (Supelco) allowed identification of the trimethylpentanes (TMP) and dimethylhexanes (DMH). The combined mass of TMP and DMH is referred to hereafter as the alkylate product . As discussed elsewhere [19], propane, an impurity in the isobutane feed, was used as an internal standard for butene conversion calculations. Since isomerization from 1-butene to 2-butene isomers is rapid over acidic catalysts, reported conversion is for all butene isomers to C5 and higher products. Isobutylene formation was not observed under any conditions. 

For the alkylation of isobutane and aromatics, the phenomena in the reactors are complicated involving numerous consecutive and simultaneous reaction steps variable and unknown kinetics for the different reactions and numerous mass transfer or diffusion steps between phases or in a specific phase (2,5). In this article, comparative processes are evaluated. Methods to improve current processes are proposed. 

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