Showing papers by "Eite Drent published in 2017"
TL;DR: In this article, the synthesis and characterization of bulky diphosphine 1,2-bis(4-phosphorinone)xylene, BPX, and its palladium complexes are described.
40 citations
Patent•
02 Feb 2017
TL;DR: In this paper, a metal complex of Formula (I) and a catalyst composition for the carbonylation of alkenes comprising the metal complex, wherein the metal is a group 10 element such as palladium, platinum or nickel, and the complex comprises a bidentate phosphine ligand.
Abstract: The present application relates to a metal complex of Formula (I) and a catalyst composition for the carbonylation of alkenes comprising the metal complex, wherein the metal is a group 10 element such as palladium, platinum or nickel, and the complex comprises a bidentate phosphine ligand. The present invention also relates to a process for the preparation of a dicarboxylic acid or ester thereof from an alkenoic acid or ester thereof, or a process for the preparation of a carboxylic acid or ester thereof from an alkene or alkenoic acid with high selectivity and activity using said metal complex or catalyst composition. The present application also relates to a method of preparing Nylon 6-6 comprising the step of copolymerising adipic acid with hexamethylenediamine.
5 citations
TL;DR: In this paper, a new isomerizing ring-closing amidocarbonylation reaction was reported using Pd catalysis with bulky diphosphane ligands, and it was deduced that N coordination of the amide moiety is responsible for a high selectivity to cyclic imide products.
Abstract: A new isomerizing ring‐closing amidocarbonylation reaction is reported using Pd catalysis with bulky diphosphane ligands. From terminal as well as internal pentenamide isomers (PAs), cyclic imides were obtained in good yield (92 %) with cationic Pd catalysts supported by bis‐PCg ligands (PCg=6‐phospha‐2,4,8‐trioxa‐1,3,5,7‐tetramethyladamant‐6‐yl). An excess of strong acid is required to obtain high selectivity for imide products. From a low‐temperature NMR study it was deduced that N coordination of the amide moiety is responsible for a high selectivity to cyclic imide products. In weakly acidic conditions, O coordination of the amide functionality leads to the formation of cyanoacids (i.e., 5‐cyanovaleric acid, 2‐methyl‐4‐cyanobutyric acid and 2‐ethyl‐3‐cyanopropionic acid). It is proposed that the formation of these cyanoacids occurs through a novel intramolecular tandem dehydrating hydroxycarbonylation reaction of PAs. This reaction also occurs in intermolecular versions of amidocarbonylation with mixtures of alkene and amide substrates. Experiments with N‐alkylated amides have been instrumental in developing mechanistic models. The strong acid co‐catalyst ensures double‐bond isomerization to occur faster than product formation, resulting in the same product mixture, irrespective of the use of terminal or internal pentenamides. The remaining challenge is to arrive at the desired adipimide by overcoming the undesirable regioselectivity caused by chelation of the amide.
3 citations