Thiol Functionalization of Cellulose Fabric: Synthesis and Characterization of a Heterogeneous Acid Catalyst

The grafting of thiol groups onto cellulosic materials represents a promising route for the development of bio-based, environmentally friendly heterogeneous acid catalysts. In this study, regenerated cellulose fabric was chemically modified through a two-step functionalization process involving preactivation and covalent grafting of -SH groups using thioglycolic acid (TGA), in the presence of p-toluenesulfonic acid (p-TsOH) as a catalyst and toluene as solvent. A parametric study was conducted to optimize reaction conditions by varying temperature, reagent concentrations, reaction time, and solvent volume. Optimal conditions were determined as follows: 0.3 equiv. of p-TsOH, 0.7 equiv. of TGA, 20 mL of toluene, at 80°C for 20 hours. Under these conditions, the grafting ratio reached 0.15, corresponding to one glucose monomer functionalized for every seven units, on average. FT-IR analysis confirmed the successful incorporation of thiol groups onto the modified matrix. These results demonstrate the potential of this material as a heterogeneous acid catalyst for applications in green chemistry.