690624-51-2

Upstream product

• 50777-76-9 (2-formylphenyl)(diphenyl)phosphine 
• 6630-33-7 ortho-bromobenzaldehyde 
• 20439-47-8 (1R,2R)-1,2-diaminocyclohexane 
• 12125-02-9 ammonium chloride 
• 829-85-6 diphenylphosphane 

Relevant academic research and scientific papers

Use of molecular weight-enlarged catalysts in a process for asymmetric, continous hydrogenation, novel molecular weight-enlarged ligands and catalysts

The first embodiment of the present invention provides a process, which includes: in a continuous process in a membrane reactor, asymmetrically hydrogenating at least one C=C, C=N or C=O double bond with a catalyst. Another embodiment of the present invention provides a ligand, which includes at least one di-1,3-aminophosphine homochiral active center; optionally, a linker; and a molecular weight-enlarging polymer; wherein the active center is bound to the molecular weight-enlarging polymer through the linker or is bound directly to the molecular weight-enlarging polymer; and wherein the linker is defined in the claims. Another embodiment of the present invention provides a process for preparing the above-noted ligand, and a catalyst that includes the above-noted ligand.

Continuous Application of Chemzymes in a Membrane Reactor: Asymmetric Transfer Hydrogenation of Acetophenone

The application of homogeneously soluble catalysts is limited by the recovery in cases where the price of the catalyst is high. Biological catalysts, enzymes, can be efficiently recycled by means of an ultrafiltration membrane due to their high molecular weight, for example, in the continuously operated membrane reactor. In order to transfer this principle to chemical catalysis, we have attached a transfer hydrogenation catalyst, first invented by Gao and Noyori, to a polymer. The resulting homogeneously soluble, polymer-bound catalyst (chemzyme) can now be retained by ultrafiltration membranes like enzymes. On applying this catalyst in continuously operated membrane reactors, a continuous isopropoxide dosage is necessary in order to compensate deactivation caused by water residues in the feed stream. Thus, high space-time yields up to 578 g L-1 d-1 and enantioselectivities up to 94% can he achieved. These results were compared to an enzyme catalyzed system consisting of a carbonyl reductase that also utilizes 2-propanol as a hydrogen source for the cofactor regeneration of NADH.