Selülozun TBAF/DMSO Çözücü Sisteminde KH2PO4 ve Na2HPO4 Tuz Karışımı Yerine Transesterifikasyonunda Katalizör Olarak Potasyum Karbonat

Abstract

Aim of study: This study's goal is to evaluate potassium carbonate as a catalyst for the transesterification of cellulose dissolved in TBAF/DMSO and to identify the optimal reaction conditions. Material and methods: First, a solvent system consisting of 33 g TBAF and 165 g DMSO was prepared for 10 g dissolving pulp in this solvent system for one hour, then the cellulose solution was generated. The catalysts were added to the solution. At reaction temperature, vinyl acetate was added to the solution and the 70-h transesterification process was started. The product was precipitated in ethyl alcohol and washed with water on a sieve, and then dried at room temperature. The effects of changes in catalyst ratio and temperature on bond acetyl groups were investigated by heterogeneous saponification method, FTIR, XRD, DSC, viscosity and solubility test. Main results: The samples' DS values ranged from 1.39 to 2.37 and using phosphate salt mixture catalyst and increasing the ratio of catalyst increased the DS. FTIR and XRD data revealed that acetylation was effective. DSC thermograms showed a minor endotherm at 283.3-291.2°C, and it was identified as the melting point. With potassium carbonate, the viscosity and the solubility of the products increased. Highlights: Cellulose in TBAF/DMSO could be acetylated using potassium carbonate as the catalyst. Potassium carbonate's catalyst activity was weak on DS.