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The synthesis of chiral compoundsthrough dynamic kinetic resolutionhas shown improved results with the presence of racemization. Integratingthe reaction media for biocatalytic kinetic resolution and base-catalyzedracemization pose challenges in chiral separation due to its alkalineenvironment. Base-catalyzed racemization of (R)-ibuprofenester has been separately studied in isooctane, isooctane–water,and isooctane–DMSO media. A rapid racemization rate of (R)-ibuprofen ester was obtained in isooctane-DMSO mediumas compared with the other two media with racemization rate constants(krac) of 0.292 and 0.001 h–1, respectively. An investigation carried out on sodium hydroxideand Amberlyst A26 (OH–resin) as base catalystshas shown that Amberlyst A26 gave a better performance compared tothat of sodium hydroxide. Additionally, the rate of racemization increasesat higher reaction temperatures, but shows otherwise at a higher concentrationof substrate. The kinetic model of the base-catalyzed racemizationwas developed and experimentally validated. The model incorporatestwo main contributing factors in the racemization reaction: a basecatalyst and initial substrate concentrations. Base-catalyzed racemizationwas conducted in the proposed packed-bed reactor, where the racemizationrate was faster with an increased velocity of feed flow rate. Theabsolute rate constants of racemization (kabs) obtained were 0.112 and 0.275 h–1for feed flowrates of 0.6 and 1.2 mL·min–1, respectively.The packed-bed reactor was then proposed to be coupled with a membranereactor as an integrated dynamic kinetic resolution reactor of chiralcompounds. [ABSTRACT FROM AUTHOR]

Ibuprofen (isobutyl-propanoic-phenolicacid) is a chiral drug well-knownfor its analgesic, antipyretic, and anti-inflammatory effects. Inthe present work, an enzymatic membrane reactor (EMR) has been developedfor the production of optically pure (S)-ibuprofenacid. The EMR is equipped with a multitubular fixed bed racemizationunit to enhance the enzymatic deracemization of (R,S)-ibuprofen ester. Several process parameterssuch as enzyme loading, racemization catalyst loading, reaction temperature,buffer pH, as well as the flow rate were investigated. These experimentalresults were then compared with the proposed process model. It wasfound that the experimental data were in good agreement with the theoreticalresults. The optimum condition of the lipase-catalyzed dynamic kineticresolution (DKR) using the EMR could give 96–98% conversionwith 97–99% of product enantiomeric excess (eep). [ABSTRACT FROM AUTHOR]