Isobutane/2-butene alkylation on dealuminated H EMT and H FAU

The alkylation of isobutane with 2-butene on dealuminated hexagonal H EMT and dealuminated cubic faujasite H FAU with Si/Al ratios of 5–6 was studied at 80°C and compared with results obtained for the as-synthesized and calcined parent material with Si/Al ratios of 3.5. In both cases, the dealuminated samples favour an improved profile with respect to the alkylate yield and selectivity after 3 h reaction time, with dealuminated H EMT as the superior system. The alkylate composition consisted of 76% and about 70% C₈ paraffins for dealuminated H EMT and dealuminated H FAU, respectively. Within the C₈ fractions the three trimethylpentanes (TMP) 2,3,3-, 2,3,4- and 2,2,4-TMP were the dominating product compounds in all tests, whereas a higher content of dimethylhexanes (DMH) was observed for the H FAUs, both dealuminated and parent material. However, among the four trimethylpentanes (2,2,3-, 2,2,4-, 2,3,3- and 2,3,4-TMP) usually the 2,3,3-TMP and 2,3,4-TMP were the main compounds formed, at least for the dealuminated samples. Oligomerization was suppressed by using the dealuminated samples, however, increasing amounts of C₈ olefins after about one half of the monitored reaction time was observed for the H FAUs. By contrast, the H EMTs exhibited much less formation of C₈ olefins (and on a constant level) even after 300 min reaction time. The deactivated samples showed mainly formation of paraffinic coke.