Preparation of phenylboronic acid based hypercrosslinked polymers for effective adsorption of chlorophenols

Hypercrosslinked polymers (HCPs) have demonstrated effective adsorption capabilities because of their rich porosity and high specific surface area. However, the HCPs prepared with phenylboronic acid based compounds as monomers via Friedel-Crafts alkylation reaction have not been reported yet. Herein, four new HCPs with phenylboronic acid (PBA), 1,4-benzenediboronic acid, 4-hydroxyphenylboronic acid and 4-carboxyphenylboronic acid as the respective monomers were prepared for the first time. Their Brunner-Emmet-Teller surface areas were 909.1 m² g^-1, 71.9 m² g^-1, 39.8 m² g^-1 and 29.3 m² g^-1, respectively. The prepared HCP with PBA as the monomer (named as PBA-HCP) displayed the best adsorption capability for chlorophenols. Then, it was investigated as a SPE adsorbent for the extraction of some chlorophenols from water and honey-pomelo beverage samples prior to high performance liquid-phase chromatography with diode array detection. The established method had low limits of detection for the analytes in the range from 0.06 to 0.2 ng mL^-1 for water samples and from 0.3 to 1.0 ng mL^-1 for honey-pomelo beverage samples. The linear response for the analytes was in the range of 0.18-100.0 ng mL^-1 for water samples and 0.9-100.0 ng mL^-1 for honey-pomelo beverage samples. The method also had a good repeatability with the relative standard deviations less than 7.1% and a fairly good accuracy with the method recoveries falling between 80.0% and 120.0%. The adsorption capacities of the PBA-HCP for 2-chlorophenol, 3-chlorophenol, 2,3-dichlorophenol and 2,4-dichlorophenol were 21.7 mg g^-1, 31.2 mg g^-1, 77.1 mg g^-1 and 82.1 mg g^-1, respectively. The PBA-HCP also exhibited excellent extraction capabilities for some other compounds, especially for those that have more hydrogen bonding sites.