Enantioselective liquid–liquid extraction of (D, L)‐valine using metal–BINAP complex as chiral extractant

Abstract

Background Enantioselective liquid–liquid extraction is a very attractive technology for the production of enantiomerically pure compounds. The objective of this research is to investigate enantioselective liquid–liquid extraction of valine (Val) enantiomers with metal–BINAP complexes as enantioselective extractants. Results Results show that BINAP complex with copper(I) as central ion allows the separation of Val enantiomers with the highest operational selectivity. Efficiency of the extraction depends, often strongly, on a number of process variables, including types of organic solvents, pH of the aqueous phase, concentration of host and substrate, and temperature. Extraction performance of the system can be accurately predicted by the model. By modeling and experiment, an optimal extraction condition was obtained at a pH of 8 and the host concentration of 2.0 × 10‐3 mol L‐1 with the highest enantioselective (α) of 3.65 and performance factor (pf) of 0.086. Conclusions The presented data indicate that Val enantiomers can be efficiently separated by enantioselective liquid–liquid extraction. The model provides a powerful tool for calculating distribution ratio, enantioselectivity, enantiomeric excess and performance factor. It can be used for optimization of the reactive extraction systems. This paper can provide some valuable fundamental data for the production of enantiomerically pure amino acid enantiomers. © 2013 Society of Chemical Industry

Selector Screening for Enantioseparation of dl‐α‐Methyl Phenylglycine Amide by Liquid–Liquid Extraction

“…The BINAP and xylyl-BINAP complexes have been reported several times recently in enantioselective liquid-liquid extraction studies, 27,29,[51][52][53][54][55] and also here they were the selectors with the highest selectivity (by far). Apparently, the amide functionality brought in a significant disturbance of the enantiorecognition mechanism for these chiral selectors.…”

“…The system was further examined in various solvents, and a less volatile alternative for DCM was found in 1chloropentane, still exhibiting selectivities up to 1.5. The BINAP and xylyl-BINAP complexes have been reported several times recently in enantioselective liquid-liquid extraction studies, 27,29,[51][52][53][54][55] and also here they were the selectors with the highest selectivity (by far). Therefore, the development of metal-BINAP-complexes appears promising to further broaden the library of hosts for enantioselective liquid-liquid extraction.…”

“…This finding shows once more the versatility of these hosts, as recently metal-BINAP-based hosts were found applicable in ELLE for a wide range of substrates. 27,29,[51][52][53][54][55] Similar to the BINAP-based hosts, binolbased phosphoric acids have recently been demonstrated to be selective for a range of benzylic amines. Therefore, these were also applied in this study.…”

Recent Development: Enantio Selective Eextraction in Chiral Separation

“…Enantio selective liquid-liquid extraction of racemic ibuprofen by l-tartaric acid derivatives as chiral selector was studied by Ren et al [18]. Enantioselective liquid-liquid extraction of (D, L)-valine using metal-BINAP complex as chiral selector was done by Tang et al [19].…”

Enantioselective Liquid–Liquid Extraction of Underivatized Amino Acids with Simple Chiral Aminophenyl‐Aldehyde

“…Enantioselective liquid–liquid extraction (ELLE) is a promising economical process due to a low energy consumption in the operation and convenience in scaling up . Versatile chiral extractors of organic and metallo‐organic compounds for ELLE have been developed . Binol‐based chiral aldehydes and ketones have been developed in our group for the extraction of underivatized amino acids through reversible imine bond formation, which are quite remarkable considering that other extractors so far developed are usually applied to the extraction of derivatized amino acids based on weak noncovalent interactions .…”