COMPARISON OF THE ISO-STRUCTURAL H-SAPO-37 AND H-FAUJASITE AS CATALYSTS FOR THE ISOBUTANE 2-BUTENE ALKYLATION/

The alkylation of isobutane with 2-butene has been studied in a slurry reactor on the iso-structural H-SAPO-37 and dealuminated faujasite (F AU) catalysts, It was found that mainly dimerization takes place on H- SAPO-37 by producing C-8 olefins. In the small fraction of C-8 paraffi ns, the 3,4-dimethylhexane (3,4 DMH) was the most abundant compound. T he dealuminated H-FAU catalyst, on the other hand, produced mainly the desired trimethylpentanes (TMPs). The number and strength of the acid sites in H-SAPO-37 and dealuminated H-FAU were investigated by NH3-TP D and IR spectroscopy, revealing a considerably higher relative concen tration of strong acid sites in the dealuminated H-FAU catalyst compar ed to H-SAPO-37. rising the ratio of pyridine adsorbed at 400 degrees C and 250 degrees C as a measure of the ratio of strong to weak acid s ites in the samples, ratios of 0.40 and 0.65 were obtained for the H-S APO-37 and dealuminated H-FAU, respectively, ranking the dealuminated H-FAU as a much better catalyst than H-SAPO-37 in the isobutane/2-bute ne alkylation reaction.