Synthesis of amorphous titanium isophthalic acid catalyst with hierarchical porosity for efficient oxidative desulfurization of model feed with minimum oxidant

Abstract

Deep desulfurization is an indispensable technique for obtaining clean fuel and the preparation of novel materials for upgrading desulfurization efficiency is highly pursued. Herein, we develop a novel amorphous titanium isophthalic acid (Ti-IPA) catalyst with hierarchical porosity and highly dispersion of Ti-OH defect sites via solvothermal method. Ti-IPA is suitable for a variety of oxidant desulfurization (ODS) reaction systems due to its amphiphilic nature. The optimal Ti-IPA reveal extraordinary ODS performance for oxidizing 1000 ppm sulfur of dibenzothiophene-to-dibenzothiophene sulfone in model feed within 12 min at 40 ℃ with minimum oxidant/sulfur molar ratio of 2 (the sulfur oxidation efficiency reached 99.5 %), and the reaction time can be altered to 5 min at 50 ℃. The activity per unit mass of Ti-IPA reaches 52.2 mmol h−1g−1 at 50 ℃, outperforming all the reported Ti-based organic materials. Quenching and EPR tests indicate that Ti-IPA adopts non-free-radical ODS mechanism. Experimental and characterization results verify that the terminal OH capped on the Ti defect sites can easily react with oxidant to form peroxo-titanium intermediates, which manipulate the sulfur oxidation efficiency.