scholarly journals Effects of Substitution Pattern in Phosphite Ligands Used in Rhodium-Catalyzed Hydroformylation on Reactivity and Hydrolysis Stability

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1036 ◽  
Author(s):  
Svenja Kloß ◽  
Detlef Selent ◽  
Anke Spannenberg ◽  
Robert Franke ◽  
Armin Börner ◽  
...  

The stability of homogeneous catalytic systems is an industrially crucial topic, which, however, receives comparatively little attention from academic research. Phosphites are among the most frequently used ligands in industrial, rhodium-catalyzed n-regioselective hydroformylation. However, they are particularly vulnerable to hydrolysis. Since the decomposition of ligands should be dependent on the substitution patterns, phenyl, tert-butyl and condensed ring systems of benzopinacolphosphites were evaluated concerning their activity, regioselectivity and hydrolysis stability. A series of twelve strongly related phosphites were synthesized, tested in the hydroformylation of isomeric n-octenes, and studied in hydrolysis experiments using in situ NMR spectroscopy. Our results show that substituents in the ortho-position, especially tert-butyl substituents, enhance hydrolysis stability while maintaining compelling activity and regioselectivity. In contrast, substituents in the para-position may destabilize the phosphite.

Author(s):  
Anagha Sasikumar ◽  
Anouar Belhboub ◽  
Camille Bacon ◽  
Alexander C. Forse ◽  
John Griffin ◽  
...  

In situ NMR spectroscopy is a powerful technique to investigate charge storage mechanisms in carbon-based supercapacitors thanks to its ability to distinguish ionic and molecular species adsorbed in the porous...


Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 102
Author(s):  
Sandun Perera ◽  
Michael Findlater

Activation of the dialkylpalladium complex (phen)Pd(CH3)2 (phen = 1,10-phenanthroline) with B(C6F5)3 affords a competent catalyst for the dimerization of vinyl silanes. All organic products of the catalytic dimerization of trialkoxyvinylsilanes were characterized by in situ NMR spectroscopy and GC–MS. The putative palladium cation was characterized by NMR spectroscopy. Upon activation, the palladium complex generated products in moderate yield (60–70%) and selectivity (~60:40, dimer:disproportionation products).


2014 ◽  
Vol 192 ◽  
pp. 55-58 ◽  
Author(s):  
Ralf Giernoth ◽  
Andreas Bröhl ◽  
Martin Brehm ◽  
Yves Lingscheid

2003 ◽  
Vol 125 (43) ◽  
pp. 13298-13302 ◽  
Author(s):  
Satyanarayana Anala ◽  
Galina E. Pavlovskaya ◽  
Prakash Pichumani ◽  
Todd J. Dieken ◽  
Michael D. Olsen ◽  
...  

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