Selective hydrogenation of oxalic acid to glycolic acid and ethylene glycol with a ruthenium catalyst

Selective Hydrogenation of Glycolic Acid to Renewable Ethylene Glycol over Supported Ruthenium Catalysts

“…70 % at 120 °C to ca. 20 % at 180 °C, similar to observations by Santos et al [25] On the other hand, selectivity towards EG compared to AA also decreases with increasing temperature regardless of the catalyst. Over commercial Ru/C, selectivity for EG decreases from 62 % at 120 °C to 6 % at 180 °C while selectivity for AA increases from 6 % to 15 %.…”

“…In that way the results here are comparable to the study of Liu et al [17] on LA hydrogenation who also could not close the carbon balance at elevated temperatures (> 120 °C). Furthermore, Santos et al [25] recently investigated the hydrogenation of oxalic acid to ethylene glycol over a Ru-based catalyst and found 87 % selectivity for gas-phase compounds at 150 °C. It will be shown below that optimized reaction conditions provide almost closed carbon balances (> 95 %).…”

Selective Reduction of Carboxylic Acids to Alcohols in the Presence of Alcohols by a Dual Bulky Transition-Metal Complex/Lewis Acid Catalyst

“…The hydrogenation of these substrates is highly promising in terms of a sustainable method for the production of one of the monomers of polyethylene terephthalate (PET) ( 2l ) from biorenewable 1l . However, due to their inherent instability, reports of the direct double reduction of both CA groups of 1l , which complements the electrochemical mono-reduction of 1l to 1m and oxalate hydrogenation to 2l , are virtually absent from the literature except for a few systems, all of which are characterized by a low selectivity toward 2l . , By conducting the esterification at low temperatures, followed by hydrogenation in a one-pot fashion, these substrates were selectively hydrogenated to yield 2l , efficiently circumventing the issues of the decomposition and in situ formation of polyesters, which are usually associated with these substrates.…”

Oxalic acid hydrogenation to glycolic acid: heterogeneous catalysts screening

“…Yet, so have others and both Lange et al, and Santos et al, have since reported further details on the reduction of oxalic acid to glycolic acid and ethylene glycol using heterogeneous catalysis. 42,43 Lange et al, presented a process to produce glycolic acid from oxalic acid. Their process made use of a hydrogenation metal catalyst and they used 4 wt% ruthenium supported on TiO 2 as a catalyst in their examples.…”

“…56 All of the DMO was converted in their reaction, with about 95% Fig. 2 Reaction mechanism for oxalic acid hydrogenation reproduced with permission from Santos et al 43 selectivity for ethylene glycol. The catalyst proved stable for 300 hours.…”