III International Conference

PP-II-126ISOBUTANE - BUTENE ALKYLATION ON SULFATED ALUMINA WITHCHLORINE-CONTAINING PROMOTORSSmirnova M.Yu., Urguntsev G.А., Vedyagin A.A., Echevsky G.V.Boreskov Institute of Catalysis SB RAS, Novosibirsk, RussiaE-mail: smirnova@catalysis.ruThe catalytic properties of the samples of sulfated alumina in the reaction of alkylation ofisobutane by butenes have been studied. Both the concentration of sulfate-ion and thetemperature of preliminary thermal treatment were varied in this investigation. Physical andchemical properties of the samples were studied by means of DTG and IR-spectroscopy usingCO molecules as a probe. It was observed that few sulfate species with different acid-base andcatalytic properties are formed over support surface depending on the initial concentration ofthe sulphatizing agent and the temperature of pretreatment. An aggregation of the sulfate ionsis occurred when its concentration exceeds monolayer quantity.In line with the global move for environmental protection, there has been considerableimprovement in gasoline materials for automotive fuels which are relatively free ofenvironmentally harmful alkenes and aromatics. A notable example of such improvedgasoline material is an alkylate containing highly branched alkane. Alkylate is an economical,clean-burning, high-octane, low volatility product.The liquid acids HF and H 2 SO 4 are the industrially used catalysts for the aliphaticalkylation. But their wide use is related with a serious problem like corrosivity and toxicity.At present there are a lot of investigations dedicated to research an alternative solid acidcatalyst to replace these liquids. Since the discovery of its strong acidity, sulfated oxides(especially zirconium) have attracted much attention as a potential catalyst.In this research the catalytic properties of the sulfated alumina has been studied in thereaction of alkylation of isobutene by butanes. It was considered for a long time that thesulfated alumina is an unpromising catalyst for the acid-catalyzed reaction due to its lowestactivity in comparison with the oxides of zirconium, tin and titanium [1, 2]. However, gammaalumina shows high thermostability at the temperatures up to 800 °C and retains its phasestate and surface area on the same level. On the other hand, zirconia and titanium oxide couldbe easily sintered at the temperature mentioned above.Moreover, it is well known that the sulfation of crystalline oxides brings to inactivecatalyst formation. That is why only amorphous oxides can be used for the preparation of thesulfated catalysts. In this view, alumina is an exception [3].394