SKELETAL ISOMERIZATION OF LINEAR BUTENES ON BORON PROMOTED FERRIERITE: Effect of the catalyst preparation technique

RAÚL A. COMELLI

CATALYSIS LETTERS

Springer Netherlands

Lugar: Holanda; Año: 2007 vol. 122 p. 302 - 309

1011-372X

Potassium and acid ferrierites were impregnated with boron species by wet and incipient wetness techniques. All samples display a medium-intensity band at 3450-3470 cm-1 associated to Si−OH•••O groups corresponding to boron-containing units. The 1398-1404 cm-1 band assigned to the B-O stretching in BO3 units does not appear on boron-potassium-ferrierite prepared by wet impregnation. Catalytic performance during the linear butene skeletal isomerization was measured. At 300ºC, boron impregnated by incipient wetness technique on acid ferrierite reduces both linear butene conversion at a short time and isobutene yield in all time range. Boron-potassium-ferrierite prepared by wet impregnation has a suitable acidity to promote isobutene production. At 450ºC, this sample shows the best performance, being the isobutene yield 1.7 times higher than the acid-ferrierite one and reaching the highest isobutene selectivity (92%). This performance is maintained with time. Both isobutene yield and by-product distribution are strongly affected by temperature; dimer intermediates are formed. Finally, both kinds of hydroxyl groups corresponding to 3466 and 3635 cm-1 bands influence the isobutene production whereas BO3 sites are inactive for this reaction.