Highly Efficient Tetradentate Ruthenium Catalyst for Ester Reduction: Especially for Hydrogenation of Fatty Acid Esters

Abstract

A new tetradentate ruthenium complex has been developed for hydrogenation of esters. The catalyst's structure features a pyridinemethanamino group and three tight chelating five-membered rings. The structure character is believed to be responsible for its high stability and high carbonylation-resistant properties. Thus, this catalyst shows outstanding performance in the catalytic hydrogenation of a variety of esters, especially for fatty acid esters, which may be used in practical applications. New insight on designing hydrogenation catalyst for reducing esters to alcohols has been provided through theoretical calculations.

CH2 Linkage Effects on the Reactivity of Bis(aminophosphine)–Ruthenium Complexes for Selective Hydrogenation of Esters into Alcohols

“…The entire catalytic hydrogenation of esters into alcohols can be assumed to proceed through two stages: hydrogenation of esters into aldehydes (stage I) and subsequent hydrogenation into alcohols (stage II) 31, 39–41 . Our calculations (Figs S11 and S12) and previous studies 36, 42, 43 propose that stage II is more favorable than stage I both kinetically and thermodynamically.…”

Chitosan as a Natural Polymer for Heterogeneous Catalysts Support: A Short Review on Its Applications

“…Ruthenium (Ru) catalyst was well used for the aqueous hydration of nitriles to amides [45] and hydrogenation of esters [46] in the organic chemical industries. A molecular Ru catalyst was also developed for the water oxidation in a photosystem to generate renewable energy [47].…”

Ruthenium and osmium complexes containing 2-(aminomethyl)pyridine (Ampy)-based ligands in catalysis

“…Zhang and co-workers starting from the consideration that the catalyst activity for reducing esters may be correlated to the hydridicity of the metal hydride (strong hydridic metal hydrides can attack the less polar C O bond of esters) and the acidity of the N H group (high acidity of the N H group can play the role of Lewis acid to activate the C O groups of esters) designed the complex 165 (Scheme 124) as a catalyst fulfilling such requisites [82]. This complex features an Ampy moiety and three tight chelating five-membered rings.…”

“…b Octadecan-1-ol (5%) was also obta ined Scheme 127. HY of fatty acid esters catalyzed by the Ru-complex 165[82].…”