Microporous hypercross-linked conjugated quinonoid chromophores of anthracene: Novel polymers for CO2 adsorption

Microporous hypercross-linked conjugated quinonoid chromophores represent a novel class of amorphous polymers, synthesized by the reaction of anthracene with dimethoxy methane in the presence of FeCl3 catalyst. Their N2 adsorption isotherms confirm their microporous nature. Diffuse reflectance UV-Visible (DRS UV-Vis) spectroscopy confirms their matrix built with the conjugated quinonoids by their broad light absorption characteristics extending from 1000 nm to 200 nm with the absorbance maximum close to 400 nm. The catalyst cross-linked anthracene with -CH2- bridges and subsequently dehydrogenating them to form quinonoids. Their Fourier transform infrared (FTIR) spectra showed their characteristic quinonoid vibrations between 1600 and 1700 cm−1. The synthesis of polymers was carried out at 30, 40, 50, 60, 70 and 80 °C, but the quinonoid content of the polymer obtained at 80 °C was higher than that of the others. Their scanning electron microscopy (SEM) images showed microspheres of 1 to 5 μm size built with tiny particles. Their surfaces were not smooth. The polymer synthesized at 80 °C showed 5.1 wt% CO2 sorption at 25 °C and 0.1 MPa, but when it was recross-linked, the CO2 sorption increased to 8 wt%. Hence, hypercross-linked conjugated quinonoid chromophores of anthracene are good for sorption of CO2.