IMPROVED SELECTIVITY TO C₈-OLEFINS FOR ISOBUTENE OLIGOMERIZATION ON NIO-W₂O₃/Al₂O₃CATALYSTS

Abstract

Isobutene oligomerization on W 2 O 3 =Al 2 O 3 and NiO-W 2 O 3 =Al 2 O 3 catalysts (20 wt.% W 2 O 3 and 5 wt.% NiO) was studied. The catalysts were prepared by impregnating ammonium tungstanate and nickel nitrate on a c-alumina sol-gel support. The XRD patterns of the samples calcined at 500 C show the presence of large W 2 O 3 conglomerates on the W 2 O 3 =Al 2 O 3 sample and smaller ones on the NiO-W 2 O 3 =Al 2 O 3 catalyst. Pyridine-FT-IR absorption spectra study shows a higher acidity on the nickel-containing sample. The isobutene oligomerization was carried out in a gasphase flow reactor (50-150 C), and selectivity as high as 100% to the formation of the C ¼ 8 olefins fraction was obtained. The role of NiO coordinating the p-allyl adsorption of the olefins as well as its role to the high C ¼ 8 selectivity were discussed.

Selective Isobutene Oligomerization by Mesoporous MSU-SBEA Catalysts

“…It is generally accepted that catalytic performance declines rapidly when GHSV is increased. Nevertheless, the lowest GHSV (32.8 h −1 ) used in this work is still much higher in comparison to the GHSV/WHSV values used in previous studies of this reaction. ,,,,− ,− ,, …”

“…Several acid solids exhibit catalytic activity for isobutene oligomerization, including sulfated zirconia, sulfated titania, ,, nickel-doped zeolites, , nickel supported on sulfated zirconia, and NiO-W 2 O 3 /Al 2 O 3 , among others. The reaction is usually performed with gas hourly space velocities (GHSV) in the 5−20 h −1 range in order to attain acceptable conversions.…”

Selective oligomerization of isobutylene in mixed C4 catalyzed by supported Fe(NO3)3/β catalyst

“…When the reaction temperature was 60 °C, the selectivity of C 8 was the highest. The loss rate of n ‐butene increased with the increase of temperature, and there was no obvious change in the loss rate of n ‐butene in the reaction temperature range 60~70 °C, which shows that the conversion rate of isobutylene can be improved and the loss rate of n ‐butene could be kept unchanged in this reaction temperature range 29 . This may be a result of the low activity of active sites exposed by the catalyst at low temperature, which is not conducive to the catalytic conversion of isobutylene.…”

Preparation of supported Fe2O3‐Cl/β‐zeolite catalyst and its application in the selective oligomerization reaction of isobutene in mixed C4

“…Supported Fe 2 O 3 ‐Cl/ β ‐zeolite catalysts with 3% and 6% Fe impregnation amounts were synthesized with the catalyst synthesis conditions unvaried. The reaction condition of the fixed‐bed reactor was controlled as follows: reaction airspeed of 1.5 h −1 and reaction pressure of 1 MPa, and reaction temperatures were changed to explore the catalytic effects of supported Fe 2 O 3 ‐Cl/ β ‐zeolite catalysts under different reaction temperatures, 29 as shown in Figs 8 and 9. As observed from Fig.…”