Obtaining xylitol by catalytic hydrogenation of xylose in thepresence of raney nickel catalyst

Xylitol is a low-calorie, five-carbon sweetener. It is a polyol used in various food applications, primarily in gum and confectionery, due to its low glycemic index (GI), non-cariogenic properties, and refreshing effect in the mouth. One of the most common methods for xylitol production is the catalytic hydrogenation of xylose. Xylose, a pentose sugar (5-carbon sugar), is derived from the hemicellulose content of biomass sources. In this thesis, xylitol production yield was monitored using a 1-liter laboratory-scale pressurized reactor and gas control system with xylose as the raw material. The reaction yield was examined concerning pressure, temperature, catalyst amount, and raw material concentration. Based on the evaluation results, it was found that the amount of Raney nickel used as the catalyst was the most influential parameter on xylitol conversion. Within the specified parameter ranges, the optimum conditions for xylitol production were determined to be 40 bar hydrogen pressure, 25%xylose concentration, 40 g catalyst, and a temperature of 140°C. Under these conditions, xylitol production was 86.6±0.2% and xylose conversion was found to be 98.35±0.2%. In the thesis study, it was determined that another parameter affecting the xylitol yield was the stirring speed. It was determined by HPLC analysis that increasing the reaction speed from 400 rpm to 800 rpm shortened the reaction time and the xylitol yield reached 98%