松木屑硝酸-乙醇法纤维素含量测定工艺的优化

Optimization of Determination Process of Cellulose Content with Pine Sawdust and Nitric Acid-ethanol Method

以松木屑为原料,对硝酸-乙醇法测定纤维素含量的工艺进行优化。采用正交试验的方法,研究一次回流时的固液比、硝酸体积分数、反应时间和反应温度对纤维素纯度的影响,并对硝酸-乙醇法所提取的纤维素进行了性能测试。结果表明单次回流的最佳工艺是:固液比为1g∶25mL,硝酸所占体积分数为25%,反应时间70min,回流温度100℃。在此工艺下,经过4次回流后,所得产物中木质素相对含量低于10%,α-纤维素含量达88.5%以上,同时原料的回流次数平均减少3次。通过XRD和FT-IR分析表明,得到了结晶度为70%左右具有较高纯度的天然纤维素。

This paper optimizes determination process of cellulose content with nitric acid-ethanol method with pine sawdust as raw material, studies the influence of solid-to-liquid ratio during single backflow, volume of nitric acid, reaction time and reaction temperature on the purity of cellulose and conducts performance test on cellulose extracted with nitric acid- ethanol method. The result shows that the optimal process of single backflow is： solid-to-liquid ratio lg ： 25mL, volume fraction of nitric acid 25 %, reaction time 70rain and backflow temperature 100℃. After backflow for four times under this process, the relative content of lignin in the product obtained is less than 10%, the content of a-cellulose reaches over 88. 5 % and meanwhile the number of backflow times of raw material decreases by 3 on average. Through XRD and FT-IR analysis, natural cellulose with relatively high purity and about 70% degree of crystallinity is obtained.