Integrated Process Optimization of Xylose Hydrogenation over Raney Nickel in a Pressurized Reactor for Xylitol Production: A Response Surface Approach with Product Verification

Xylitol is a leading low-calorie sugar alcohol worldwide. Industrial production efficiency has become crucial given the increasing global demand. The catalytic hydrogenation of xylose to produce xylitol is a leading method. In this study, xylitol production using a Raney nickel catalyst was optimized in a pressurized batch reactor. The catalyst amount, xylose concentration, hydrogen pressure, and temperature were used as the process variables, and the maximum yield (%) was determined. The experimental design, created using a central composite design (CCD), was optimized using Response Surface Methodology (RSM), and the obtained values were evaluated using ANOVA. The linear regression model was found to be statistically significant. The linear model indicated that temperature had no effect on the model. The optimal conditions determined by the RSM were 40 g of catalyst, 25% xylose, and 60 bar at 400 rpm stirring. The yield was 86.61%, which is quite close to the predicted value of 87.2557%, demonstrating the accuracy of the model. The product was analyzed using HPLC, XRD, DSC, TGA, and ICP-MS to confirm product quality. Under these optimized chemical conditions, increasing the stirring speed to 800 rpm as a post-optimization step led to a further increase in yield up to 98.01%, indicating the presence of mass transfer limitations at lower mixing intensities.