高温高压制备微晶纤维素新工艺

New technology for microcrystalline cellulose preparation in high temperature and pressure

高温高压制备微晶纤维素工艺与传统的制备工艺的反应机理相近,随着处理液pH值、时间、温度、压力等反应相关因素的调整,其反应进程发生重大变化,并且产生与传统工艺截然不同的结果。实验结果表明,制备过程因素影响关系为:酸浓度<处理时间<水解温度;从得率对比情况看,高温高压制备微晶纤维素的工艺水解反应时间过长,则纤维素反应物明显减少,其得率明显偏低,合理控制处理时间是保证有效得率的重要环节。从不同工艺条件下微晶纤维素得率角度,高温高压制备微晶纤维素的最佳工艺为:盐酸浓度取2.5%、处理时间为180 min、水解温度为130℃;但以表面膨胀体积为参照系时,高温高压制备微晶纤维素的最佳工艺为:此时盐酸浓度应取1.0%、处理时间为120 min、水解温度为150℃。

Preparation of microcrystalline cellulose in high temperature and pressure is similar to the conventional one in terms of reaction mechanism.However,given that the reaction is significantly influenced by the pH value of treatment solution,reaction time,temperature and pressure,products of the new technology are totally different from those of the conventional technology.The experimental results showed that,when ranked by influence,parameters affecting the reaction were acid concentration,treatment time and hydrolysis temperature.It was found that the long-time reaction in high temperature and pressure would result in low cellulose content in reaction products.Therefore,it was important to limit the reaction time to a reasonable duration.When evaluated by cellulose content in the reaction products,the optimal acid concentration,treatment time and hydrolysis temperature were 2.5%,180min and 130℃,respectively.When evaluated by volume expansion,the optimal values of the above parameters were 1.0%,120min and 150℃,respectively.