scholarly journals Spectroscopic study on the active site of a SiO2 supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

2016 ◽  
Vol 18 (32) ◽  
pp. 22636-22646 ◽  
Author(s):  
M. M. Maronna ◽  
E. C. Kruissink ◽  
R. F. Parton ◽  
F. Soulimani ◽  
B. M. Weckhuysen ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Gas Phase ◽  
Active Site ◽  
Beckmann Rearrangement ◽  
Cyclohexanone Oxime ◽  
Surface Species ◽  
Acidic Site

Formation of a Brønsted-acidic site out of a Lewis-acidic mono-oxo NbO4 surface species and ethanol, catalysed by a Lewis-basic molecule, e.g. pyridine or cyclohexanone oxime.

Gas phase beckmann rearrangement of cyclohexanone oxime over zirconia-supported boria catalyst

1999 ◽  
Vol 188 (1-2) ◽  
pp. 361-368 ◽  
Author(s):  
Bo-Qing Xu ◽  
Shi-Biao Cheng ◽  
Shan Jiang ◽  
Qi-Ming Zhu
Keyword(s):  
Gas Phase ◽  
Beckmann Rearrangement ◽  
Cyclohexanone Oxime

Kinetic Study on Gas-Phase Beckmann Rearrangement of Cyclohexanone Oxime to ε-Caprolactam over a Silica-Supported Niobia Catalyst

2016 ◽  
Vol 55 (5) ◽  
pp. 1202-1214 ◽  
Author(s):  
M. M. Maronna ◽  
E. C. Kruissink ◽  
J. T. Tinge ◽  
D. W. Agar ◽  
W. F. Hoelderich
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Beckmann Rearrangement ◽  
Cyclohexanone Oxime

Regioselective Gas-Phase n-Butane Transfer Dehydrogenation via Silica-Supported Pincer-Iridium Complexes

2020 ◽  
Author(s):  
Boris Sheludko ◽  
Cristina Castro ◽  
Chaitanya Khalap ◽  
Thomas Emge ◽  
Alan Goldman ◽  
...  
Keyword(s):  
Gas Phase ◽  
Active Site ◽  
Lower Cost ◽  
Open Systems ◽  
Iridium Complexes ◽  
Terminal Olefin ◽  
Molecular Precursors ◽  
Sterically Demanding ◽  
Olefin Production ◽  
Steam Cracking

<b>Abstract:</b> The production of olefins via on-purpose dehydrogenation of alkanes allows for a more efficient, selective and lower cost alternative to processes such as steam cracking. Silica-supported pincer-iridium complexes of the form [(≡SiO-<sup>R4</sup>POCOP)Ir(CO)] (<sup>R4</sup>POCOP = κ<sup>3</sup>-C<sub>6</sub>H<sub>3</sub>-2,6-(OPR<sub>2</sub>)<sub>2</sub>) are effective for acceptorless alkane dehydrogenation, and have been shown stable up to 300 °C. However, while solution-phase analogues of such species have demonstrated high regioselectivity for terminal olefin production under transfer dehydrogenation conditions at or below 240 °C, in open systems at 300 °C, regioselectivity under acceptorless dehydrogenation conditions is consistently low. In this work, complexes <a>[(≡SiO-<i><sup>t</sup></i><sup>Bu4</sup>POCOP)Ir(CO)] </a>(<b>1</b>) and [(≡SiO-<i><sup>i</sup></i><sup>Pr4</sup>PCP)Ir(CO)] (<b>2</b>) were synthesized via immobilization of molecular precursors. These complexes were used for gas-phase butane transfer dehydrogenation using increasingly sterically demanding olefins, resulting in observed selectivities of up to 77%. The results indicate that the active site is conserved upon immobilization.

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