三氟乙酸催化玉米秸秆纤维素制备三醋酸纤维素研究

Preparation of Cellulose Triacetate from Corn Stover Cellulose by Trifluoroacetic Acid

以玉米秸秆纤维素为原料,以三氟乙酸(Trifluoroacetic acid,TFA)为催化剂,提出采用一锅法高效制备三醋酸纤维素(Cellulose triacetate,CTA)的新工艺,并进行了合成试验。以CTA的取代度和产率为指标,分析了TFA添加量、反应温度、反应时间以及乙酸酐添加量对CTA取代度及产率的影响,并优化了合成工艺,结果表明,CTA的最佳制备条件为:TFA添加量15 mL/g、反应温度25℃、反应时间30 min、乙酸酐添加量5 mL/g,得到的CTA的取代度为2.95,产率为96.2%。通过傅里叶变换红外光谱分析、X射线衍射分析以及氢核磁共振分析对产物理化特性进行了表征,结果表明,纤维素发生了乙酰化反应,并合成了CTA;热重分析结果表明,该工艺制备的CTA具有较高的热稳定性。

Cellulose acetate is a material widely used in industrial fields.Cellulose triacetate(CTA)was synthesized by a one-pot method using corn stover cellulose as raw material and trifluoroacetic acid(TFA)as catalyst.The effects of TFA content,reacting temperature,reacting time and acetic anhydride content on the degree of substitution and yield of CTA were studied.At the same time,the synthesis process of cellulose triacetate was optimized.The results showed that the optimal optimization conditions for CTA were as follows:the content of TFA was 15 mL/g,the reacting temperature was 25℃,the reaction time was 30 min,and the content of acetic anhydride was 5 mL/g.Under these conditions,the degree of substitution and yield of CTA were 2.95 and 96.2%,respectively.Fourier transform infrared spectroscopy,X-ray diffraction analysis and hydrogen nuclear magnetic resonance analysis were used to characterize the physical and chemical properties of the product.The results showed that acetylation of cellulose occurred and CTA was synthesized.The thermogravimetric analysis results showed that the CTA prepared by this process had better thermal stability and the purity of the product was higher.A process for the efficient preparation of corn stover cellulose CTA with one-pot method was constructed,which provided a way for the high-value utilization of corn stover.At the same time,the method can recover the catalyst TFA without adding additional solvents,reducing costs while reducing resource consumption.It can provide certain theoretical basis and technical support for the efficient utilization of corn stalks and the industrial production of cellulose acetate in the future.