具有较高表面活性的木质素磺酸盐的制备

摘要

Lignosulfonates were prepared by sulfonation of lignin product purchased from the market that was obtained from plant stalk with mild technological process;followed by neutralization with sodium hydroxide. Different sulfonation methods were used separately such as Na2 SO3 method,Na2 SO3 - CuSO4 method, Na2 SO3 -FeCl3 method,Na2 SO3 -formaldehyde method,Na2 SO3 -formaldehyde-FeCl3 method,sulfuric acid method and fuming sulfuric acid method. Both surface tension at air/water and interfacial tension at n -heptane/water of the aqueous solutions of lignosulfonate products were measured by drop volume method. Acid-base titration method,infrared spectra and thermal gravity analysis were used to characterize the starting material and the sulfonated products prepared. The results showed that the surface activity of lignosulfonates obtained is relatively high,especially for the products prepared by Na2 SO3 method,Na2 SO3 -FeCl3 method and sulfuric acid method whose surface tension can be as low as 34-38 mN/m (25 ℃). This work showed that surface activity of the lignosulfonate products may greatly depend on the uniformity as well as content of the acidic groups in the starting lignin material.%以提取自植物秸秆的、采取温和工艺制得的市售木质素为原料，分别采用亚硫酸钠法、亚硫酸钠－硫酸铜法、亚硫酸钠－氯化铁法、亚硫酸钠－甲醛法、亚硫酸钠－甲醛－氯化铁法、硫酸法和发烟硫酸法对木质素进行磺化。采用滴体积法测定了中和后产物溶液的表面张力和与正庚烷的界面张力。通过酸碱滴定、红外光谱和热重分析对原料及磺化产物进行表征。结果表明，所得木质素磺酸钠降低表面张力的能力较强，其中通过亚硫酸钠法、亚硫酸钠－氯化铁法和硫酸法处理得到的产物磺化度较高，中和后产物的水溶液表面张力可低至34～38 mN／m （25℃）。推测原料木质素的结构较均一、自身酸性基团含量高等因素对其磺化产物的表面活性起重要作用。