Catalysis of Organic..

62Isobutene TrimerizationResults and DiscussionThe oligomerization of isobutene in function of the time is shown in Figures 1 and 2for the sultated TiO 2 and NiY zeolite catalysts respectively. After a stabilization timeof 2 hours on stream, the sulfated TiO 2 catalyst showed initial conversion valuesafter 3 h in stream of 100, 70, 65 and 42% at GHSV of 8, 16, 32 and 64 h -1 ,respectively (Fig. 1). For the NiY zeolite catalyst the activities were 56, 43, 33 and17% for the previous GHSV values respectively (Fig. 2).Conversion of Isobutene, %1007550258 h -116 h -132 h -164 h -101 2 3 4 5 6 7 8hoursFigure 1 Conversion of isobutene over “in situ” sulfated TiO 2 catalyst at differentGHSV values.Conversion of Isobutene, %1008060408 h -116 h -132 h -164 h -12001 2 3 4 5 6 7 8hoursFigure 2 Conversion of isobutene over NiY catalyst at different GHSV values.