Low severity upgrading of F-T waxes with solid superacids. Quarterly report, December 1, 1992--February 28, 1993

Technical Report · Fri Mar 26 04:00:00 EST 1993

DOI:https://doi.org/10.2172/10139849· OSTI ID:10139849

Tierney, J W; Wender, I

In the last quarters a new class of solid superacids, including sulfated zirconium-hafnium oxides and ZrO{sub 2}/SO{sub 4} modified by Mn and Fe, were synthesized and shown to be active for isomerization and hydrocracking of hexadecane (n-C{sub 16}H{sub 34}). The reaction was carried out in a tubing bomb under mild conditions: 2.5 MPa and 433 K. Pt/HfO{sub 2}S0{sub 4} catalyst exhibited a low activity for hydrocracking of n-C{sub 16}, but the addition of ZrO{sub 2} to the sulfated hafnium improved its activity considerably. An 85 wt % conversion level was achieved when the molar ratio of ZrO{sub 2} to HfO{sub 2} reached 1:1, indicating the possibility of a synergistic effect between zirconium and hafnium. It has recently been reported that Mn,Fe/ZrO{sub 2}/SO{sub 4} is about three orders of magnitude more active than ZrO{sub 2}/SO{sub 4} for isomerizing n-butane. As a result, an 0.5%Mn1.5%Fe/ZrO{sub 2}/SO{sub 4} catalyst was prepared according to a procedure given in a patent. It was found that, without Pt, the catalyst was inactive for hydrocracking of n-C{sub 16}, possibly by deactivation due to coking. It is interesting that a 68 wt % conversion level was achieved after incorporation of Pt along with a product distribution that was shifted towards longer chain paraffins. ZrO{sub 2}/SO{sub 4}has been reported to be a superacid with H{sub 0} < {minus}16 as measured by the Hammett indicator method. However, the acid strength of some ZrO{sub 2}/SO{sub 4} based catalysts, such as the mentioned catalysts, could not be measured by using Hammett indicators because the catalysts are colored gray. We successfully modified an in situ FT-IR analytical system to characterize the acidity of these catalysts. We have applied the method using pyridine as adsorbate to demonstrate their acid strength. Preliminary results indicated a level of acidity of our catalysts which is consistent with their performance in hydrocracking of n-C{sub 16}.

• Research Organization: Pittsburgh Univ., PA (United States). Dept. of Chemical and Petroleum Engineering
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG22-91PC91304
• OSTI ID: 10139849
• Report Number(s): DOE/PC/91304--T5; ON: DE93011453
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010408
C1 PROCESSES
CATALYSTS
FISCHER-TROPSCH SYNTHESIS
HAFNIUM OXIDES
HEXADECANE
HYDROCRACKING
ISOMERIZATION
PH VALUE
PLATINUM
PROGRESS REPORT
REFINING
SULFATES
WAXES
ZIRCONIUM OXIDES