Ezgi Akceylan

Removal efficiency of a calix(4)arene-based polymer for water-soluble carcinogenic direct azo dyes and aromatic amines

A Mannich base derivative of 5,11,17,23-tetrakis-[(1,4-dioxa-8-azaspiro-[4.5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix[4]arene 3 was synthesized by the treatment of calix[4]arene with a cyclic secondary amine (1,4-dioxa-8-azaspiro-[4.5]decane) and formaldehyde. The compound 3 was treated with dibromoxylene to obtain a calix[4]arene-based copolymer 4. In batch sorption experiments of selected carcinogenic azo dyes and aromatic amines, the compounds 3 and 4 were found to be a better sorbent for azo dyes than for the aromatic amines. It was observed that the percentage of azo dye removal was 95-99% for compound 3 and 83-97% for 4 when the pH of the dye solution was in the range of 2.0-8.0. The sorption of azo dyes and aromatic amines by calix[4]arenes-based compounds indicates that amino groups play the major role for the formation of hydrogen bonds and electrostatic interactions.

Polymer Supported Calix[4]Arene Derivatives for the Extraction of Metals and Dichromate Anions

Three newly synthesized polymer supported calix[4]arene ionophores (7–9) were synthesized, and their ion binding properties toward selected alkali (Li+, Na+, K+, Cs+) and transition metal (Hg2+, Ni2+, Cu2+, Co2+, Cd2+, and Pb2+) cations were investigated. It has been observed that these ionophores are not selective toward a particular metal cation but show better ion binding property as compared to monomeric calixarene derivatives (2 and 6). Ionophore 6 and its supported polymer were also employed in dichromate anion extraction experiments. The polymeric ionophore (9) was found an effective extractant for dichromate anion even at pH 7.

Immobilization of Cyclic Alkylamine Calix[4]arene Derivatives on Merrifield Resin: Evaluation of Extraction Ability Toward Dichromate

Two new calix[4]arene‐based polymeric resins were synthesized via nucleophilic substitution reactions involving 5,11,17,23‐tetrakis(N‐piperidinomethyl)‐25,26,27,28‐tetrahydroxycalix[4]arene ( 2 ) and 5,11,17,23‐tetrakis[4‐carboethoxy‐N‐piperidino]‐25,26,27,28‐tetrahydroxycalix[4]arene ( 4 ) as precursors with Merrifield resin. Extraction studies were performed by liquid–liquid extraction and solid–liquid adsorption procedures. The monomeric compounds showed excellent extraction ability toward dichromate in liquid–liquid extraction systems. Polymeric resin 3 with calixarene moieties exhibited high adsorption properties, while resin 5 showed lower adsorption of dichromate in solid–liquid extractions.

Facilitated Transport of Cr(VI) through Polymer Inclusion Membrane System Containing Calix[4]arene Derivative as Carrier Agent

Chromium(VI) is one of the major toxic elements present in environmental samples. The polymer inclusion membrane (PIM), has been developed to provide metal ion transport with high selectivity. This study was conducted to discover efficient methods for removing Cr(VI) from wastewater. A functionalized calix[4]arene carrier 1 in a PIM system was used to transport Cr(VI) from an acidic aqueous donor phase solution to an acceptor phase that contained an acetic acid/ammonium acetate solution at pH 6. The prepared PIM was characterized with Fourier Transform Infrared (FT-IR) spectroscopy and the Atomic Force Microscopy (AFM) techniques as well as with contact angle measurements. The efficiency of Cr(VI) transport through the PIM was investigated by studying the effects of carrier concentration on the membrane phase as well as by measuring the amount of plasticizer in the membrane, the pH in the acceptor phase and the membranes stability and thickness. The kinetic parameters were calculated as rate constant (k), permeability coefficient (P), flux (J) and diffusion coefficient (Do). The transport efficiency of Cr(VI) was observed to be 98.61% after 10 h under optimized conditions. The experimental results show that Cr(VI) can transport from the donor phase to the acceptor phase with high efficiency through the PIM. The results also suggest that the transport efficiency of the PIM was reproducible and that a PIM is effective for long-term separation processes.

Carcinogenic direct azo dye removal from aqueous solution by amino-functionalized calix[4]arenes

This study contains a convenient synthesis and azo dye extraction efficiency of amino-functionalized calix[4]arene derivatives. Two calix[4]arene derivatives bearing alkyl amino groups on their upper and lower rim have been successfully synthesized and used as extractant for dye removal in liquid–liquid extraction system. The effect of electrolyte concentration, contact time, and pH on azo dye extraction was also investigated for all calixarene derivatives. From the results, it has been deduced that the amino-functionalized calix[4]arenes showed a better affinity than other parent calix[4]arenes towards the selected azo dyes.

Enantioselective hydrolysis of (R,S)-Naproxen methyl ester using Candida rugosa lipase with calix[4]arene derivatives

Candida rugosa lipase has been immobilized on a variety of calix[4]arene derivatives using the sol–gel encapsulation technique, and the catalytic activities of the resulting encapsulated lipases towards the hydrolysis of p-nitrophenyl palmitate and the hydrolytic kinetic resolution of racemic Naproxen methyl ester were evaluated using standard techniques. The results revealed that the calix[4]arene-based immobilized encapsulated lipases 5-CRL and 6-CRL gave higher levels of enantioselectivity and conversion than the free encapsulated lipase.

Chiral Calix[4]arenes-Bearing Prolinamide Functionality as Organocatalyst for Asymmetric Direct Aldol Reactions in Water

ABSTRACT The chiral calix[4]arene derivative (6) bearing an L-prolinamido group has been designed and proved to be a water compatible efficient organocatalysts for a direct enantioselective aldol reaction. Compound 6 catalyzes the aldol reaction of cyclohexanone and a variety of aromatic aldehydes yielding anti-aldol products in high yield with enantioselectivities of up to 93% and diastereoselectivity of up to 95:5.

Synthesis and properties of calix[4]arene polymers containing amide groups: Exploration of their extraction properties towards dichromate and nitrite anions

AbstractThe article describes the synthesis and extraction properties of three new diamide substituted calix[4] arene based polymers (3a, 4a, and 5a). The examination of their recognition abilities towards some selected oxyanions shows that the new calix[4]arene polymers are more effective receptors than their amide derivatives for dichromate anions and nitrite. It has been observed that receptor 4a is a better extractant for dichromate and nitrite anions at low pH.

Preparation of Calix[4]arene Alkylamine Derivatives by Mannich Reaction and use as Phase-Transfer Catalysts for Esterification Reaction

In this study, 5,11,17,23-tetrakis[(N-ethylpiperazine)methyl]-25,26,27,28-tetrahydroxycalix[4]arene (3) and 5,11,17,23-tetrakis[(4-carboethoxy-N-piperidino) methyl]-25,26,27,28-tetrahydroxycalix[4]arene (4) were synthesized in one step according to the Mannich reaction by the treatment of calix[4]arene with a secondary amine (N-ethylpiperazine, ethyl-4-piperidincarboxylate) and formaldehyde. The calix[4]arene derivatives (3, 4) were characterized by a combination of FTIR, 1H NMR and elemental analyses. The synthesized compounds were used in an esterification reaction as the phase transfer catalyst. The catalytic efficiency of the calix[4]arenes 3 and 4 was evaluated by carrying out the ester-forming reaction of alkali metal carboxylates (sodium butyrate or sodium caprylate) with p-nitrobenzyl bromide. It was observed that the ester-forming reaction of alkali metal carboxylates with p-nitrobenzyl bromide, using calix[4]arene-based catalyst 3 as a phase-transfer catalyst in dichloromethan, provided the best yields.

Synthesis of Water-Soluble Calixarenes Catalyzed One-Pot Mannich-Type Reaction in Aqueous Media

This article demonstrates the synthesis of new water soluble calix[4]arenes (8) based catalyst and application in one-pot, three component Mannich reactions to catalyze reaction between aromatic ketones/aldehyde and amines to acquire β-Amino carbonyl compounds in appreciable yields at room temperature in aqueous media.