Isomerization-cracking of n-octane on Ptx H3-xPW12O40 supported on ZrO2 catalysts

GERARDO C. TORRES; DEBORA L. MANUALE; VIVIANA M. BENÍTEZ; JUAN M. BADANO; JORGE H. SEPÚLVEDA; JUAN C. YORI

QUíMICA NOVA

SOC BRASILEIRA QUIMICA

Lugar: San Pablo; Año: 2012

0100-4042

The hydromerization-cracking of n-octane was studied using catalysts based on H3PW12O40 (HPA) supported over zirconia and promoted with Pt.  The addition of Pt to the supported HPA samples does not modify the total acidity substantially but the Brönsted acidity is remarkably increased. A linear relation between n-C8 total conversion at 5 min time-on-stream and Brönsted acidity was showed. The selectivity pattern of catalysts point to a simple mechanism of transformation in which n-C8 is isomerized to yield i-C8 that is subsequently broken mainly in middle positions.  Finally one part of the produced n-C4 is isomerized to i-C4. So the principals products of conversion n-C8 were n-C4;  n-C5;  i-C4; i-C5 and i-C8. The most adequate for performing the isomerization and cracking to yield high RON (Research Octane Number) are catalyst with higher values of Brönsted acidity