Synthesis of calixarenes and their extraction performance for ester catechins

A series of extractants （tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene） were synthesized, and their structures were identified by IR and JH-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants, concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate （GCG） than with epigallocathechin gallate （EGCG） or epicatechin gallate （ECG）. When the concentration ofp-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 ℃, the partition coefficients ofKGCG, KECG, KEGCG are 0.987, 0.629, 0.449, the separation factors of al and a2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.

A series of extractants (tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene) were synthesized, and their structures were identified by IR and 1H-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants, concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate (GCG) than with epigallocathechin gallate (EGCG) or epicatechin gallate (ECG). When the concentration of p-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 ℃, the partition coefficients of KGCG, KECG, KEGCG are 0.987, 0.629, 0.449,the separation factors of α1 and α2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.