Positional isomerization of butene-2 over nanoporous MCM-48 catalysts

Positional isomerization of butene-2 to butene-1 was investigated over nanoporous MCM-48 catalysts. The effects of the method and the amount of aluminum incorporation into MCM-48 on the catalyst characteristics were studied, with respect to the butene-2 isomerization reaction. Incorporation of aluminum into MCM-48 using a post-synthetic grafting method (P) or direct sol-gel method (D) increases the total acid amount due to the increase in the Lewis acidity level. From the results of butene-2 isomerization, the yield of butene-1 was increased although the selectivity of butene-1 was decreased due to an increase of byproducts such as i-butene, cracked fraction, and C ₅+ hydrocarbons. This trend is nearly identical over both catalyst preparation methods; the effect of Al incorporation method on the butene-1 yield and the selectivity appeared negligible. The maximum yield of butene-1 was 27.1 wt% by feeding pure butene-2 in the reaction condition as follows: a temperature of 450 °C, atmospheric pressure, and with the WHSV at 70 h ^-1.