Enantioseparation through liquid extraction technology is an emerging field, e.g., enantioseparations of amino acids (and derivatives thereof), amino alcohols, amines, and carboxylic acids have been reported. Often, when a new selector is developed, the versatility of substrate scope is investigated. From an industrial point of view, the problem is typically approached the other way around, and for a target racemate, a selector needs to be found in order to accomplish the desired enantioseparation. This study presents such a screening approach for the separation of the enantiomers of DL-¿-methyl phenylglycine amide (DL-¿-MPGA), a model amide racemate with high industrial relevance. Chiral selectors that were reported for other classes of racemates were investigated, i.e., several macrocyclic selectors and Pd-BINAP complexes. It appeared very challenging to obtain both high extraction yields and good enantioselectivity for most selectors, but Pd-BINAP-based selectors performed well, with enantioselectivities up to 7.4 with an extraction yield of the desired enantiomer of 95.8%. These high enantioselectivities were obtained using dichloromethane as solvent. Using less volatile chlorobenzene or 1-chloropentane, reasonable selectivities of up to 1.7 were measured, making these the best alternative solvents for dichloromethane. Chirality 27:123¿130, 2015@en

Solvent impregnated resins (SIRs) were evaluated for the recovery of pyridine derivatives from an aqueous waste-stream containing also acetic acid and succinonitrile. For this purpose, a new solvent was developed, synthesized and impregnated in Amberlite XAD4. Sorption studies were used to determine the capacity, selectivity and the mass-transfer rate. A high capacity of 21 g 4-yanopyridine (CP) per kg SIR was found, with very high selectivity toward CP over the other solutes of at least 570. A modified Langmuir equation could describe the equilibrium sorption isotherm. Both the linear driving force model and a Fickian diffusion model were evaluated. The Fick-model described both regeneration and loading best. The CP-diffusivity through the solvent phase was estimated at 6.53 10 13 ± 2.5% m2 s 1. The model was validated using fixed-bed column experiments. The R2 values for this model ranged between 0.94 at a flow rate of 5 mL/min and 0.99 at a flow rate of 1 mL/min during the loading cycle. Due to mass-transfer limitations the breakthrough profiles were broad and breakthrough occurred after 5 or 23 bed volumes, for flow rates of 5 and 1 mL/min, respectively. Both acetic acid and succinonitrile broke through immediately due to the very high CP-selectivity of the SIR.@en