Marek Blahušiak

New approach to regeneration of an ionic liquid containing solvent by molecular distillation

A promising new process for the regeneration of solvents with ionic liquid by molecular distillation has been proposed. The main advantage of this process compared with the classic stripping of acids with alkali solution is that the volatile organic acid is recovered with a yield of about 88 % in the form of free acid, not as its salt. Furthermore, improvement on the yield of the stripping can be assumed. The consumption of chemicals in stripping by molecular distillation is reduced.

Selector screening for enantioseparation of DL-α-methyl phenylglycine amide by liquid-liquid extraction.

Enantioseparation through liquid extraction technology is an emerging field, e.g.,u2009enantioseparations 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-α-methyl phenylglycine amide (DL-α-MPGA), a model amide racemate with high industrial relevance. Chiral selectors that were reported for other classes of racemates were investigated, i.e.,u2009several 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.

Hybrid Adsorption–Microfiltration Process with Plug Flow of Microparticulate Adsorbent for Boron Removal

Application potential of a hybrid adsorption–microfiltration (AMF) process utilizing a microparticulate adsorbent for fast adsorption kinetics was analyzed for boron removal from the reverse osmosis permeate in a seawater desalination plant. The suspension of microparticulate Dowex XUS-43594 adsorbent can be effectively concentrated by microfiltration (MF) to high dry adsorbent concentrations of 24 mass% for a ceramic membrane in a cross-flow tubular module and of 11 mass% for a hydrophilic capillary membrane in a submerged module. Backwashing has been proved to be an efficient way of achieving prolonged MF operation at a flux higher than its critical values. Utilization of the microparticulate adsorbent in the AMF process allows decreasing of the chemicals and energy consumption compared to a classical water treatment process in ion-exchange columns. Diafiltration of the regenerated adsorbent suspension decreases the consumption of chemicals and adsorbent flow rate in the desorption loop of the adsorbent.

CO2-Switchable Solvents as Entrainer in Fluid Separations

CO2-switchable solvents, typically neutral solvents that switch with CO2 into ionic species, were investigated for use as entrainer in fluid separations such as extractive distillation. Their switchable nature was investigated, which may facilitate liquid–liquid extraction or extractive distillation as ionic liquid (IL), whereas during regeneration their decarboxylation into the amine form prevents temperature shoot-up. Studied elements included a property screening and detailed mechanistic and kinetic studies on the switching of 2-ethylhexylamine and N,N-benzyl methylamine. Decarboxylation of a 50 vol % switchable solvent, 25 vol % heptane, and 25 vol % toluene mixture at 1.00 × 104 Pa showed a 40% CO2 release before reaching the operational pressure, and total decarboxylation took over 2 h. An effective increase of the relative volatility of heptane/toluene was found, showing that, indeed, CO2-switchable solvents can be applied for extractive distillation. However, low pressure in combination with elevated temperature will lead to quick decarboxylation, limiting the operational window of this class of solvents. Their use in low temperature application such as C4-distillations or liquid–liquid extraction appears more suited.