Metal Oxides as Catalysts for the Process of Xylan Sulfation with Sulfamic Acid

Abstract

Xylan sulfate, a derivative of hemicelluloses in aqueous form, exhibits a diverse array of biological activities and finds applications across multiple domains. For the first time, the efficacy of metal oxides as catalysts in the sulfation of xylan using sulfamic acid and 1,4-dioxane has been systematically explored. The findings indicate that calcium oxide emerges as the most effective catalyst, yielding both superior amounts of xylan sulfate and a significantly high sulfur content within the compound. The incorporation of sulfate groups into the xylan macromolecule was substantiated through a combination of infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis. To enhance the performance of the optimal catalyst, a thorough numerical optimization of the sulfation process was undertaken. A mathematical model describing this process was established, focusing on key output parameters, namely the sulfur content in the generated xylan sulfate and the overall yield of sulfated xylan. Consequently, the ideal reaction conditions were identified, enabling the maximization of both the yield of xylan sulfate and its sulfur content