화학공학소재연구정보센터
Chemical Engineering Science, Vol.66, No.3, 397-404, 2011
Reaction kinetics in reactive extraction for chiral separation of alpha-cyclohexyl-mandelic acid enantiomers with hydroxypropyl-beta-cyclodextrin
This paper reports on determination of the intrinsic reaction kinetics in reactive extraction of alpha-cyclohexyl-mandelic acid (alpha-CHMA) enantiomers with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) in a modified Lewis cell, in which HP-beta-CD dissolved in 0.1mol/l NaH2PO4/H3PO4 buffer solution was selected as chiral extractant. alpha-CHMA enantiomers were extracted from an organic phase to an aqueous phase in the extraction module. The theory of extraction accompanied by chemical reactions has been used to obtain the intrinsic kinetics of this extraction module. The different factors affecting the extraction rate, such as agitation speed, interfacial area, initial enantiomers concentration in an organic phase as well as HP-beta-CD concentration in an aqueous phase were separately studied. The experimental results demonstrate that the extraction reaction kinetics is fast. The reactions between alpha-CHMA enantiomers and HP-beta-CD in a stirred cell fall in regime 3 and are first order with respect to alpha-CHMA enantiomers and second order with respect to HP-beta-CD with forward rate constants of 6.9 x 10(-2) m(6)/(mol(2) s) and 2.5 x 10(-2) m(6)/(mol(2) s) for S-alpha-CHMA and R-alpha-CHMA, respectively. These data will be useful in the design of the extraction process. (C) 2010 Elsevier Ltd. All rights reserved.