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to support sulfated zirconia catalysts on MCM-41, the mesoporous molecular sieve originally prepared by researchers at Mobil. Authors use the material to catalyze n-butane isomerization. Author explained that as worldwide demand for clean fuels rises, manufacturers are eliminating aromatic compounds from fuel supplies and looking to branched alkanes and other compounds to maintain high octane ratings. He noted that sulfated zirconia is an attractive catalyst to use for isomerizing straight-chain alkanes because the solid acid is active at low temperatures and offers environmental benefits compared with liquid acids.
Looking to further boost catalyst performance, author studied the effects of chemical additives known as promoters. They found that adding just 5 mol% alumina increased sulfated zirconia's activity by a factor of 10. After scrutinizing the catalyst system with a battery of characterization techniques, the authors concluded that the transformation of zirconia that typically occurs in unpromoted catalysts--from the catalytically active tetragonal phase to the monoclinic phase--is suppressed in the alumina-promoted catalysts. But with or without the promoter, much of the catalyst's activity is due to the nanoporous support, which leads to highly dispersed nanosized catalyst particles
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