Hydrogenation of dimethyl oxalate to ethylene glycol on Cu/SiO2 catalysts prepared by a deposition-decomposition method: Optimization of the operating conditions and pre-reduction procedure

Cu/SiO 2 catalysts prepared by a deposition-decomposition (DD) method using ammonium hydroxide are currently among the most promising for oxalates hydrogenation to ethylene glycol (EG). Here, catalyst DD was pre-reduced at a) 200–350 °C in 100% H , and 2) 200 50% /N mixture. Then, it tested °C, 25 barg, while EG yields were optimized, with -GHSV /DMO ratios ranges 1000–4000 h −1 30–200 mol/mol. The calcined presents an XRD amorphous Cu phyllosilicate phase. After pre-reduction pure 200–250 (T red ), metallic surface area increased from 6 12 m /g cat slightly decreased 350 °C. Simultaneously, silanol's band, measured DRIFT experiments, T . highest yield (91%) achieved after hydrogen, working of 1050 68 mol/mol, respectively. stable more than 36 20 induction period. Catalyst characterization results as function confirm that mixed-valence copper nanoparticles favor selective formation, side reactions leading ethanol 1,2-butanediol related exposed acidic basic sites due Cu/support interactions. • interacting support limits acidic/basic sites. Large amounts unreduced lead methyl glycolate decomposition. Pre-reducing optimizes yields. above decreases support. Low – interaction increases Guerbet Hydrodeoxygenation by-products.