Sulfur Poisoning on Rh Nanoparticles but Sulfur Promotion on Its Single-Site Catalyst for Carbonylation

Abstract Sulfur poisoning is a challenge for most nanoparticle metal catalysts. A trace amount of sulfur contaminants could result in dramatic catalytic activity reduction or even irreversible deactivation1-5. Therefore, new approaches to enhance the catalyst sulfur-resistance have continuously attracted attention from academia and industry. Herein, a role reversal of sulfur from poison to promotor is presented for an Rh-based heterogeneous catalyst from supported Rh nanoparticles (NPs) to its single-site catalysts (Rh1/AC, AC: activated carbon) in methanol carbonylation, ethylene and acetylene hydrocarboxylic reaction with a feed containing 1000 ppm H2S (S-feed). In situ free-electron laser/time of flight mass spectrometry (In situ FEL/TOF MS) indicated that H2S could be quickly transformed into catalyst-friendly CH3SCH3 and/or CH3SH on the Rh1/AC, which coordinated with the Rh ions and promoted its methanol carbonylation reaction, possessing a lower energy barrier based on DFT calculations. On the contrary, strong adsorption of H2S on the surface of Rh NPs inhibited the reaction of reactants.

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Isospecific propylene polymerization with in situ generated bis(phenoxy-amine)zirconium and hafnium single site catalysts

Dalton Transactions ◽

10.1039/c3dt00058c ◽

2013 ◽

Vol 42 (25) ◽

pp. 9112 ◽

Cited By ~ 9

Author(s):

Haruyuki Makio ◽

Aitha Vishwa Prasad ◽

Hiroshi Terao ◽

Junji Saito ◽

Terunori Fujita

Keyword(s):

Single Site ◽

Propylene Polymerization ◽

Single Site Catalysts

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Olefin Oligomerization by Main Group Ga3+ and Zn2+ Single Site Catalysts

10.21203/rs.3.rs-94946/v1 ◽

2020 ◽

Author(s):

Nicole LiBretto ◽

Yinan Xu ◽

Aubrey Quigley ◽

Ethan Edwards ◽

Rhea Nargund ◽

...

Keyword(s):

Molecular Weight ◽

Equilibrium Distribution ◽

Transition Metal Ions ◽

Main Group ◽

Single Site ◽

Main Group Metal ◽

Hydride Elimination ◽

Single Site Catalysts ◽

Olefin Oligomerization

Abstract In heterogeneous catalysis, olefin oligomerization is typically performed on immobilized transition metal ions, such as Ni2+ and Cr3+. Here we report that silica-supported, single site catalysts containing immobilized, main group Zn2+ and Ga3+ ions catalyze ethylene and propylene oligomerization to an equilibrium distribution of linear olefins with rates similar to that of Ni2+. The molecular weight distribution of products formed on Zn2+ is similar to Ni2+; while Ga3+ forms higher molecular weight olefins. In situ spectroscopic and computational studies suggest that oligomerization unexpectedly occurs by the Cossee-Arlman mechanism via metal hydride and metal alkyl intermediates formed during olefin insertion and β-hydride elimination elementary steps. Initiation of the catalytic cycle is proposed to occur by heterolytic C-H dissociation of ethylene, which occurs at about 250°C where oligomerization is catalytically relevant. This work reports new chemistry for main group metal catalysts with potential for development of new olefin processes.

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Olefin oligomerization by main group Ga3+ and Zn2+ single site catalysts on SiO2

Nature Communications ◽

10.1038/s41467-021-22512-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Nicole J. LiBretto ◽

Yinan Xu ◽

Aubrey Quigley ◽

Ethan Edwards ◽

Rhea Nargund ◽

...

Keyword(s):

Molecular Weight ◽

Equilibrium Distribution ◽

Transition Metal Ions ◽

Main Group ◽

Single Site ◽

Main Group Metal ◽

Hydride Elimination ◽

Single Site Catalysts ◽

Olefin Oligomerization

AbstractIn heterogeneous catalysis, olefin oligomerization is typically performed on immobilized transition metal ions, such as Ni2+ and Cr3+. Here we report that silica-supported, single site catalysts containing immobilized, main group Zn2+ and Ga3+ ion sites catalyze ethylene and propylene oligomerization to an equilibrium distribution of linear olefins with rates similar to that of Ni2+. The molecular weight distribution of products formed on Zn2+ is similar to Ni2+, while Ga3+ forms higher molecular weight olefins. In situ spectroscopic and computational studies suggest that oligomerization unexpectedly occurs by the Cossee-Arlman mechanism via metal hydride and metal alkyl intermediates formed during olefin insertion and β-hydride elimination elementary steps. Initiation of the catalytic cycle is proposed to occur by heterolytic C-H dissociation of ethylene, which occurs at about 250 °C where oligomerization is catalytically relevant. This work illuminates new chemistry for main group metal catalysts with potential for development of new oligomerization processes.

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