Fuentes, Jose A.; Janka, Mesfin E.; Rodgers, Jody; Fontenot, Kevin J.; Buhl, Michael; Slawin, Alexandra M. Z.; Clarke, Matthew L. published their research in Organometallics on December 13 ,2021. The article was titled 《Effect of Ligand Backbone on the Selectivity and Stability of Rhodium Hydroformylation Catalysts Derived from Phospholane-Phosphites》.Recommanded Product: (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol The article contains the following contents:
A study on how ligand backbone structure has an impact on selectivity, rate, and catalyst stability of hydroformylation catalysts was prompted by some longer-term stability issues being discovered for a phospholane-phosphite with a [-CH2O-] backbone. Phospholane-phosphite ligands were synthesized. Catalysts made in situ from these ligands and [Rh(acac)(CO)2] gave iso-butanal selectivities up to 75% at 75-105°: the latter being a benchmark for iso-selectivity in reactions conducted at industrially meaningful temperatures A racemic Rh complex of a bidentate phospholane-phosphite from a tropos-biphenol with an extended backbone showed unusually high stability at high temperatures, combined with even better iso-selectivity in propene hydroformylation relative to the original complex. A related ligand with an electron-withdrawing group maintained the unusually high stability and improved activity. Characterization of the precatalysts [RhH(CO)2(L)] was accomplished using in situ HPIR spectroscopy and backed up by d. functional theory calculations (B3PW91-D3 level) and by NMR studies; the latter showed that the variation of the backbone also had a pronounced impact on the precatalyst structure. A key finding is that it is now possible to prepare phospholane-phosphite ligands that deliver high iso-butanal selectivity and that show no signs of degradation after several days even above typical reaction temperatures In one stability test, several kilograms of aldehydes were produced with TOF and selectivity being consistent over several days. In the experiment, the researchers used (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol(cas: 329735-68-4Recommanded Product: (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol)
(R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol(cas: 329735-68-4) belongs to phenols. Phenols are more acidic than typical alcohols. The acidity of the hydroxyl group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids (their pKa is usually between 10 and 12).Recommanded Product: (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol
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