Study On The Preparation Of Xylose From Paddy Hull By Acid Hydrolysis

Paddy hull is the cellulosic residue of paddy processing. In this article, hemicellulose of paddy hull was hydrolyzed into xylose while sulphuric acid was used as the catalyzer. The research was provided with academic, social and economic value.Xylose was produced in hydrolysis of hemicellulose under catalyzing by dilute acid. Some investigations were presented in experiment. Firstly, reaction conditions which performed influence on experiment were confirmed. These influence factors were the ratio of solid to liquid, concentration of sulphuric acid, hydrolysis temperature and reaction time. In order to a maximal yield of deoxidize sugar and xylose, the value range of influence factors was obtained through single factor experiments of hydrolysis. Secondly, on the basis of perpendicular design experiment, the optimal hydrolysis conditions were mass ratio of solid to liquid 1∶6, concentration of sulphuric acid 3.0wt%, hydrolysis temperature 120℃and reaction time 2h. Under the condition, 9.1wt% xylose yield was obtained. When the hydrolysis conditions were mass ratio of solid to liquid 1∶6, concentration of sulphuric acid 3.0wt%, hydrolysis temperature 120℃and reaction time 3h, deoxidize sugar had a maximal yield and hemicellulose had good utilization. Finally, the product produced in experiment was analyzed by melting-point measure, IR and HPLC. As the result, the melting point of xylose crystal was 140～147℃, IR spectrum diagram of xylose produced in experiment was consistent with spectrum diagram of standard xylose, the pure of xylose was 95.4% through HPLC.If the residue of xylose was not utilized and largely stacked in experiment, it would bring environmental problem. Some single factor experiments were carried out to inspect the influence of active temperature, concentration of phosphorous acid and active time. Through these experiments, the conditions were confirmed to active temperature 400℃, concentration of phosphorous acid 40 wt% and active time 1h. The active carbon had excellent discolor power and yield under the condition.