Transesterification of propylene glycol methyl ether in chromatographic reactors using anion exchange resin as a catalyst.

Reactive chromatography using an anion exchange resin is proposed for a transesterification reaction of propylene glycol methyl ether (DOWANOL™ PM) with ethyl acetate to produce propylene glycol methyl ether acetate (DOWANOL™ PMA). This reaction is studied in batch and chromatographic reactors catalyzed by an anion exchange resin. Several anion exchange resins are tested and compared based on the performance of resin as an adsorbent and a catalyst.

Optimization of reactive simulated moving bed systems with modulation of feed concentration for production of glycol ether ester.

In this article, we extend the simulated moving bed reactor (SMBR) mode of operation to the production of propylene glycol methyl ether acetate (DOWANOL™ PMA glycol ether) through the esterification of 1-methoxy-2-propanol (DOWANOL™ PM glycol ether) and acetic acid using AMBERLYST™ 15 as a catalyst and adsorbent. In addition, for the first time, we integrate the concept of modulation of the feed concentration (ModiCon) to SMBR operation. The performance of the conventional (constant feed) and ModiCon operation modes of SMBR are analyzed and compared.

Evaluation of tertiary pyridine resin for the separation of lanthanides by simulated moving-bed chromatography.

Lanthanide separation by simulated moving-bed chromatography was studied as a model system for separating lanthanide fission products and minor actinides from used nuclear fuels. The simulated moving-bed system was modeled for a tertiary pyridine anion-exchange resin supported on silica particles as the stationary phase and a mixture of methanol and 1 M nitric acid as the mobile phase. Pulse injection tests using a single packed column were used to obtain chromatographic parameters for mathematical modeling of the simulated moving-bed system.

Systematic optimization and experimental validation of ternary simulated moving bed chromatography systems.

Over the past several decades, many modifications have been proposed in SMB chromatography in order to effectively separate a binary mixture. However, the separation of a multi-component mixture using SMB is still one of the major challenges. Recently, a computational study was performed which compared various existing isocratic ternary separation operating schemes (including the JO process) in terms of the maximum throughput attained, and Generalized Full Cycle strategy was proposed based on a systematic design, which was found to have significant improvement over existing strategies [Agrawal and Kawajiri (2012)].

Evaluation of the potential of nonlinear gradients for separating a ternary mixture.

The potential of applying nonlinear gradients in preparative chromatography is evaluated theoretically and experimentally. The second eluting component of a ternary model mixture is considered as the target component. Systematic gradient resolution experiments were conducted for this mixture using reversed phase chromatography.

Theoretical study of preparative chromatography using closed-loop recycling with an initial gradient.

Complementing classical isocratic elution, several more sophisticated operating modes have been proposed and are applied in preparative chromatography in order to improve performance. One such approach is gradient elution, where the solvent strength is altered by varying the fraction of a modifier added to the mobile phase to enhance selectivity and to achieve faster elution. Another useful technique is closed-loop recycling, allowing better peak resolution and increased yields.

Preparative separation of multi-component mixtures using stationary phase gradients.

Solvent gradients have been widely applied in analytical and preparative chromatography to enhance selectivity and improve productivity. Recently, an alternative concept using solid phase gradients was introduced in analytical chromatography [Nyiredy, Szucs, Szepesy, Chromatographia 63 (2006) 3; Nyiredy, Szucs, Szepesy, J. Chromatogr.