高取代度羧甲基松木纤维素制备工艺优化及表征

以松木纤维素为原料,氯乙酸钠为醚化剂,采用浓碱预处理,醚化过程中两次加碱法制备高取代度羧甲基松木纤维素。以单因素实验的方法对反应条件进行优化,探讨了浓碱预处理及醚化两阶段中碱浓度、温度、处理时间、固液比及醚化剂用量各因素对产品取代度的影响。结果表明其制备最佳工艺为：浓碱预处理为NaOH质量分数40%,固液比1g∶35mL,温度30℃,时间1.5h;醚化阶段工艺为NaOH的用量2g,氯乙酸钠的用量4.3g,固液比1g∶20mL。第一阶段加入质量分数50%的碱剂和70%的氯乙酸钠,温度35℃、时间1.5h,第二阶段加入剩余的碱剂和醚化剂,温度75℃、时间2h,在此条件下制得取代度高达1.237的羧甲基松木纤维素,并采用红外光谱和XRD对产物结构进行了表征。

Preparation Process Optimization and Characterization of Carboxymethyl Pine Cellulose with High Degree of Substitution

This study prepares carboxymethyl pine cellulose with high degree of substitution with pine cellulose as raw material and sodium chloroacetate as etherifying agent with the method of alkali adding for twice in concentrated alkaline pretreatment and etherifying process,optimizes reaction conditions with the method of single factor experiment and discusses the influence of alkali concentration,temperature,processing time,solid-to-liquid ratio and dosage of etherifying agent in concentrated alkaline pretreatment and etherifying stages on the degree of substitution of products.The result shows that the optimal preparation process is as below：concentrated alkaline pretreatment：NaOH mass fraction 40%,solid-to-liquid ratio1g∶35mL,temperature 30℃,time 1.5h;etherifying stage：NaOH dosage 2g,sodium chloroacetate dosage 4.3g,solid-to-liquid ratio 1g∶20mL.Alkaline agent of 50% mass fraction and sodium chloroacetate of 70% mass fraction added in the first stage,temperature 35℃and time 1.5h;residual alkaline agent and etherifying agent added in the second stage,temperature 75℃and time 2h.This study prepares carboxymethyl pine cellulose with the degree of substitution up to 1.237 under such conditions and characterizes the product structure with infrared spectroscopy and XRD.