Experimental Study of the Reaction Kinetics for the Production of Xylitol from Xylose Laden Waste Streams

Abstract

A statistically designed study was conducted to ascertain the kinetics of conversion of xylose to xylitol using borohydrogentaion. Batch kinetic experiments were carried out for the reaction of xylose and sodium borohydride in the presence of sodium hydroxide solution. Analysis of xylose concentration-time data showed that the reaction order kinetics with respect to xylose follows a first-order rate law. This finding supports the mechanistic theory that the first hydride transfer is the rate determining step. The study shows rate constants to be 3.44 ×10-31/s and 9.76 ×10-3 1/s at 25 ⁰C and 60 ⁰C. Additionally, the activation energy and frequency factor were 31.74 kJ/mol and 19146.72 kJ/mol, respectively. Furthermore, a two-level factorial design was used to determine the influence of specific parameters, namely: initial xylose concentration, temperature, and reaction time. The analysis of these reaction factors indicated that the most significant factor was time, followed by temperature and then concentration. Furthermore, interactions between time and concentration and the three-way interaction were significant.