Mechanism of byproducts formation in the isobutane/butene alkylation on HY zeolites

Abstract

Submicron-size HY zeolites with a particles size of 200–700 nm were synthesized employing a crystal precipitation method in this study.

New Insights into the Progress on the Isobutane/Butene Alkylation Reaction and Related Processes for High-Quality Fuel Production. A Critical Review

“…It is generally found that catalysts with strong Brønsted sites are more efficient for the alkylation reaction than oligomerization. 51 Other parameters, such as the spatial distribution of activity within catalyst particles, mass transfer, diffusional limitation, and intraparticle heat effects, were also discussed. Although alkylation processes based on solid acids are not operational so far, some companies have developed processes (see Table 4).…”

“…62 Fortunately, the deactivation of zeolites was reversible and could be entirely recovered by several treatments; for example, coked zeolite is regenerated by both partial liquid-phase hydrogenative treatment at reaction conditions and complete liquid-phase hydrogenative regeneration at high temperature, as hydrogen was shown to be very effective for the regeneration of the catalysts. 63,64 Y zeolites are the most studied catalysts for alkylation, 51 as they proved to be less prone to deactivation than other types of zeolites such as zeolite X, mordenite, ZSM, and MCM-1 and showed high selectivity to isooctane. Nevertheless, the alkylation efficiency of some zeolites such as LaY was not satisfactory because of the short lifespan of the zeolite and low selectivity to isooctane.…”

“…Hence, it is necessary to enforce the studies on Y zeolites. 51 It has long been known that tailoring the acidity of the zeolite can also improve the selectivity toward the desired product (TMPs), with stronger Brønsted/Lewis site ratios favoring higher TMP selectivity and longer lifetime. Stated differently, if the residual from high carbon covered the acid sites, the diffusion of products to the bulk would decrease, and the adsorption of the reactant on activity sites will be inhibited, which in turn will cause the deactivation of the catalyst.…”

Research progress on catalytic pyrolysis and reuse of waste plastics and petroleum sludge

“…The olefin then obtains H + from the catalyst surface to form a carbocation, and the carbocation preferentially breaks into a small molecular hydrocarbon containing primary and secondary carbon ions at the β position, and then isomerized to a more stable tertiary carbon ion. [88] Finally, the stable tertiary carbon ion returns H + to the catalyst, and turns itself into an olefin and other more useful hydrocarbons. [89] Fig.…”

Preparation of CuHY catalyst via solid-state ion exchange method and its catalytic performance in isobutane/2-butene alkylation

“…High I/O ratio is usually adopted to inhibit the oligomerization of olens, especially when xed bed reactor is used. 16,17,28 With higher I/O ratio, the olen concentration around the catalytic center is lower, inhibiting the further reaction of alkyl carbocations with other olens which forms undesired heavier products. [29][30][31] There are many advantages of increasing the I/O ratio, but this is mainly achieved by enhancing the I/O ratio in feed and the recycle of isobutane is inevitable, which largely increases operating cost.…”