利用紫外分光光度法优化麦草碱木素磺化工艺

利用紫外分光光度法测定麦草碱木素磺化反应过程的吸光度变化来优化磺化反应的工艺。以傅里叶红外光谱确定在实验条件下发生了磺化反应,并生成了木素磺酸盐产物。在实验涉及的反应温度范围内,碱木素在介质中的溶解度很小,用280nm处的紫外吸光度来检测木素的溶出,发现未磺化木素的吸光值基本不变,而随着木素的磺化反应进行,溶液的吸光值增加,证实紫外分光光度法对磺化过程表征具有可行性。以紫外分光光度法为表征手段,主要考察了碱木素磺化反应的主要因素,包括反应温度、保温时间、磺化剂浓度和pH。实验结果表明,碱木素直接磺化的较佳反应条件为:反应温度125℃、保温时间3h、Na2SO3为30%(相对于碱木素绝干质量的百分比)、pH4.0。

Optimization of Sulphonation of Wheat Straw Alkali Lignin by UV Spectrophotometry

UV spectrophotometry was used to optimize sulphonation of wheat straw alkali lignin by measuring the change of absorbance during sulphonation.In the reaction temperature range,alkali lignin can dissolve only a small amount in the solvent and the absorbance at 280 nm of the solution remained basically unchanged,while the absorbance increased during the reaction,which indicated that UV spectrophotometry was feasible to monitor the sulphonating process.By analyzing the UV-ABS results,some of the most important parameters were studied and the optimum reaction conditions were decided as follows: temperature 125℃,reaction time 3 hours,dosage of sulphonating agent Na2SO3 30% and pH 4.0.