Conversion to Formic Acid and Dimethylformamide

These reactions have been investigated since the 1970s. Palladium, rhodium, nickel, ruthenium, and iridium complexes proved to be active catalysts, but at first with only low conversions. In the 1990s, these reactions were picked up again, first by Graf and Leitner [84] with Rh catalysts, then by Jessop and co-workers [85] and Baiker and co-workers [86] with Ru complexes. An enormous increase in activity was achieved in the synthesis of formic acid a turnover frequency (TOF) of 95 000 h 1 was obtained and for DMF a TOF of 370 000h 1. 

Both reactions could be carried out in a liquid-liquid two-phase system with the advantages of easy product separation and efficient catalyst recycling. In the presence of a water-soluble ruthenium catalyst with the ligand triphenylphosphine trisulfo-nate, simultaneous extraction of the organic product phase by N,N-dibutylformamide can be achieved [87, 88]. 

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