A NOVEL RHODIUM-TRI-N-ALKYLPHOSPHINE CATALYST SYSTEM FOR THE HYDROGENATION OF CARBON MONOXIDE, FORMALDEHYDE, AND GLYCOLALDEHYDE

Abstract

Syngas treatment of a mixture from rhodium compound, a large equimolar tri-n-alkylphosphine, or tri(α-nonsubstituted alkyl)phosphine, and a solvent gives rise to an orange yellow solution, which is a highly active catalyst for hydrogenation of carbon monoxide to ethylene glycol and methanol. Similarly, under syngas condition, formaldehyde and glycolaldehyde are effectively hydrogenated to methanol and ethylene glycol, respectively, by the same orange yellow catalyst solution.

Direct Synthesis of Ethylene Glycol from Syngas

“…By using Rh 4 (CO) 12 catalyst and triisopropylphosphine promoter (P iÀ Pr 3 ) in the 1-Methyl-2-pyrrolidone (NMP) solvent, turn-over frequencies for ethylene glycol was 6.2 and the selectivity of EG can reach to 58.8 % at 220 °C and under 436 atm. Some similar catalysts and promoters are also used in this reaction, [66,67] but showed different results in different solvents and conditions. During that period, some studies also used the addition of different promoters to improve the yield or selectivity.…”

“…In addition, there are many published studies on the synthesis of EG from formaldehyde or glycolaldehyde using Rh or Ru catalyst, but the reaction conditions are relatively mild. [40,67,[88][89][90] For example, in the study of Watanabe et al, [67] Rh(CO) 2 (acac) catalyst and tripropylphosphine (P nÀ Pr 3 ) promoter were used to synthesize EG from glycolaldehyde. At 98 atm and 80 °C, the TOF of EG was 371, and the selectivity was as high as 96 %.…”

Hydrocarbonylation of Aldehydes and their Derivatives

“…Rhodium [74] and ruthenium [75] homogeneous systems are known to be active in catalyzing this reaction and particularly those based on Rh ,used in the hYdroformylation step, are also active for this second step even if not so effective as other heterogeneous catalysts. Among these last the most efficient are Pd/C and PtlC [28,45], whereas copper chromite displays a low activity and selectivity.…”