Formamides from carbon dioxide, amines and hydrogen in the presence of metal complexes

Homogeneous Hydrogenation of Carbon Dioxide

“…Higher yields of 1.6 to 1.9 are found for the reaction in organic solvents [18] and in supercritical CO 2 (scCO 2 ) [30,31]. One of the most active catalysts to date, RhCl(TPPTS) 3 , is used in water, despite the very poor solubility of H 2 in that medium. acid has been produced and essentially all of the base is protonated.…”

“…Because the reaction in the absence of base is thermodynamically unfavorable, added base must still stabilize the formic acid product, even after 1 equiv. These advantages are particularly important for the RuH 2 (PMe 3 ) 4 and RuCl(OAc)(PMe 3 ) 4 catalyst precursors [30,31,35] because the hydrogenation rate is first order with respect to both H 2 and CO 2 [36]. In fact, HCO 2 H and NEt 3 are known [32][33][34] to exist in relatively stable adducts of various ratios, including 1 : 1, 2 : 1, and 3 : 1, plus unprotonated amine (even at 3 : 1 acid : amine ratios) and oligomeric chains of formic acid molecules ending with an amine.…”

Use of carbon dioxide in industrial organic syntheses

“…Kohnle and co-workers from the Shell Development Co. published the synthesis of dimethyl formamide from carbon dioxide, hydrogen and dimethylamine [74]. By using homogeneous cobalt, rhodium, iridium or palladium complexes as catalysts, they were able to produce DMF under moderate reaction conditions (100 to 125 "C).…”

Highly Efficient Ruthenium‐Catalyzed N‐Formylation of Amines with H2 and CO2

“…[5] In 1970 Haynes reported the first homogeneous catalyst for the preparation of DMF from CO 2 ,H 2 ,a nd dimethylamine with at urnover number (TON) up to 1200. [6] An elegant procedure for DMF synthesis was reported by Noyori and co-workers in 1994, and TONs of up to 370 000 were achieved at 100 8 8Cw ith 80 atm H 2 in supercritical CO 2 (130 atm) using [RuCl 2 {P(CH 3 ) 3 } 4 ]asthe catalyst. [7] Extension to bulkier dialkylamines was less successful, and resulted in lower activity (TON < 820 2 for the production of DMF (TON of up to 5100).…”