Dehydrogenation, disproportionation and transfer hydrogenation reactions of formic acid catalyzed by molybdenum hydride compounds

Abstract

Cyclopentadienyl molybdenum hydride compounds are catalysts for dehydrogenation, disproportionation and transfer hydrogenation reactions of formic acid, in which the latter provides a means to reduce aldehydes and ketones.

The Golden Age of Transfer Hydrogenation

“…595 The results obtained with these two molybdenum catalysts should trigger the further development of molybdenumcatalyzed TH. Rhenium complexes have recently been reported as catalysts in TH of CO, CC, and CN bonds (Scheme 79) since the pioneering work in this field by Toste and Kwong et al 602,603 Togni's group 597 synthesized new air-and moisturestable rhenium complexes such as 208 that have chiral ferrocenyldiphosphine ligands of the Josiphos family and used them as catalysts in the ATH of ketones using 2-PrOH as reducing reagent and substoichiometric amounts of triethylamine as base.…”

Biogenic Formic Acid as a Green Hydrogen Carrier

“…Secondly, synthesis gas is converted to methanol using Cu‐based heterogeneous catalysts at typically 220–260 °C and 70–80 bar . The next step is the carboxylation of methanol with additional CO to generate the intermediate formic acid methyl ester, which is typically at 80 °C and 45 bar using a Na methoxide catalyst . The final step is the subsequent hydrolysis of the ester using an excess of water at typically 100–140 °C and 1 bar in order to produce FA and methanol, whereby the latter can be recycled back into the former step and initiate a new reaction sequence …”

“…[23][24][25] Then ext step is the carboxylationo fm ethanol with additional CO to generatet he intermediate formic acid methyl ester, which is typically at 80 8Cand 45 bar using aNamethoxide catalyst. [26] Thef inal step is the subsequent hydrolysis of the ester using an excess of water at typically 100-140 8Ca nd 1bar in order to produce FA and methanol, wherebythe latter can be recycled backi nto the former step and initiatean ew reaction sequence. [25,27] In the last years,e lectrochemical reduction of carbon dioxide was suggested asa na lternative way to produce FA.…”

Carbon Dioxide to Methanol: The Aqueous Catalytic Way at Room Temperature

“…[3,4] In addition, both FA and MeOH may be utilizeda se asy-to-handle H 2 storagem edia. [15][16][17] To date, the bestr esultsf or the FA disproportionation reactionr eport aM eOH yield of 50 %( with 50 %c ompeting dehydrogenation) in THF at 150 8C, in the presence of aruthenium-phosphine catalyst andamethanesulfonic acid additive. [6] In recent years, an umber of groups has investigated the conversion of CO 2 derivatives or CO 2 to methanoli nt he presence of homogeneous catalysts.…”

“…[7][8][9][10][11][12][13][14] Commonf eatures of these works wereh igh temperatures (over 100 8C), the employment of organic solvents, and, in certain cases, low selectivities. [15][16][17] To date, the bestr esultsf or the FA disproportionation reactionr eport aM eOH yield of 50 %( with 50 %c ompeting dehydrogenation) in THF at 150 8C, in the presence of aruthenium-phosphine catalyst andamethanesulfonic acid additive. (1)] and disproportionation of the latter into methanol [Eq.…”