In order to improve selective inclusion of cyclodextrin (CD) and permeate f
lux, separation of structural isomers (o-, m- and p-nitrophenols) and optic
al isomers (D- and L-phenylalanines) were conducted using some modified or
and beta-CDs, glucosyl (G1)-, maltosyl (G2)-, hydroxy-propyl (HP)-, alpha-
and beta-CDs, according to the previously proposed separation method. Gener
ally, rejections of the modified CD are more enhanced than parent alpha-CD
and beta-CD by YM1 (molecular weight cut-off (MWCO) of 1000 Da), PLBC (MWCO
of 3000 Da) and YM5 (MWCO of 5000 Da) membranes. The G2-beta-CD and HP-bet
a-CD are rejected perfectly by YM1 membrane. Rejections of the modified CDs
by PLBC and YM5 membranes decrease by more than 20% of those of the YM1 me
mbrane. The selectivities of p-nitrophenol to o- or m-nitrophenol are enhan
ced with more modified alpha-CDs by YM1 membrane than those of parent alpha
-CD. The selectivities decrease the PLBC and YM-5 membranes sharply. Howeve
r, no enhancement occurs in the selectivities with modified beta-CDs. L-phe
nylalanine is included, which is stronger than D-phenylalanine with all mod
ified beta-CDs. Their selectivities are higher than that of the parent beta
-CD. We proposed a new recycle system of isomers separation based on these
data to apply the method for practical use. (C) 2000 Elsevier Science B.V.
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