58676-27-0Relevant academic research and scientific papers
Silica Hybrid Gel Catalysts Containing Group(VIII) Transition Metal Complexes: Preparation, Structural, and Catalytic Properties in the Synthesis of N,N-Dimethylformamide and Methyl Formate from Supercritical Carbon Dioxide
Kroecher, Oliver,Koeppel, Rene A.,Froeba, Michael,Baiker, Alfons
, p. 284 - 298 (2007/10/03)
Sol-gel derived hybrid materials containing group(VIII) transition metal complexes in a porous silica network were prepared and tested for the catalytic synthesis of N,N-dimethylformamide (dmf) and methyl formate (mf) from supercritical carbon dioxide, hydrogen, and dimethylamine and methanol/triethylamine, respectively. Bifunctional silylether phosphines X = Ph2P(CH2)2Si(OEt)3 and Y = Me2P(CH2)2Si(OEt)3 were used as ligands for the preparation of complexes of the type RuCl2X3, RuCl2Y3, MClX3 (M = Ir, Rh), and MCl2X2 (M = Pt, Pd). The silylether complexes were anchored in a silica matrix by co-condensation with Si(OEt)4. The textural and structural properties of the hybrid gels were characterized by means of 31P and 29Si NMR spectroscopy, extended X-ray absorption fine structure (EXAFS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and nitrogen and argon physisorption. 31P NMR spectroscopy confirmed nondestructive immobilization of the Ru, Pt, Pd, Rh, and Ir complexes. TEM and XRD analyses proved the homogeneity and noncrystallinity of the materials. The degree of condensation of the gels and the molecular mixing of the components has been investigated by solid state 29Si NMR spectroscopy. Textural characterization showed that all gels were micro- to mesoporous. EXAFS measurements indicated no metal-metal interactions, confirming that the organometallic complexes were immobilized as monomers. From all catalysts silica matrix stabilized ruthenium complexes exhibited highest activities at 100% selectivity in dmf synthesis from CO2, H2, and dimethylamine. The corresponding turnover frequency (TOF) of 1860 h-1 exceeded those reported so far for heterogeneous catalysts by a factor of 600. In methyl formate synthesis, TOFs up to 115 h-1 were reached.
Sol-gel derived hybrid materials as heterogeneous catalysts for the synthesis of N,N-dimethylformamide from supercritical carbon dioxide
Kroecher, Oliver,Koeppel, Rene A.,Baiker, Alfons
, p. 1497 - 1498 (2007/10/03)
Hybrid materials derived from group VIII metal-chloro complexes of the type MCl2X2 (M = Pt, Pd), MClX3 (M = Rh, Ir) and especially RuCl2X3 [X = Ph2P(CH2)2Si(OEt)3, Me2P(CH2)2Si(OEt)3] by cocondensation with Si(OEt)4 via a sol-gel process are highly active heterogeneous catalysts for the synthesis of N,N-dimethylformamide (dmf) from CO2, H2 and dimethylamine under supercritical conditions, affording turnover numbers up to 110 800 at 100% selectivity.
