Extraction of indene from local pyrolysis oil and its usage for synthesis of a cationite

Abstract

Keeping the principles of sustainability in view, this work explores the extraction of indene from pyrolysis oil—a complex by-product of the Ustyurt Gas-Chemical Complex—and its transformation into a novel cationite, highlighting sustainable approaches in chemical engineering and material science. Utilizing advanced analytical techniques, including thermogravimetric analysis (TG), chromato-mass spectrometry, and Fourier-transform infrared spectroscopy (FT-IR), indene was efficiently isolated and characterized. The indene extracted exhibited a principal ion peak at a molecular mass (m/z) of 117.0, confirming its purity and potential for further applications. Following extraction, indene underwent sulfonation and polycondensation with 35% formalin under specific conditions (100–110°C, 30–40 atm), resulting in a cationite with a yield of 71%. This synthesized IESA (indene-based sulfonated aromatic cation exchanger), demonstrated significant chemical–physical properties when compared to commercial equivalents, such as a moisture content significantly lower than the KU-2-8 (29.4% vs. 48–58%), and a dynamic exchange capacity (DEC) competitive with industry standards (472 mmol/m³ vs. 500–520 mmol/m³). The study not only showcases the potential of pyrolysis oil as a valuable feedstock for producing high-value chemical products, but also advances the development of new materials from industrial by-products.