两性木质素分散剂的合成及表征

Synthesis and characterization of lignin amphoteric dispersant

以亚硫酸氢钠为磺化剂,对木质素磺酸钙进行磺化;以十六烷基二甲基叔胺、环氧氯丙烷为原料,合成了中间体(2,3-环氧丙基)十六烷基二甲基氯化铵;再以四丁基溴化铵为相转移催化剂,与磺化木质素磺酸钙(SL)的酚羟基反应,合成了木质素两性表面活性剂(LAS).通过正交试验确定了最佳磺化条件:磺化剂用量2.0 g,反应时间8 h,反应温度95℃,木质素磺酸钙的相对磺化度为1.284;LAS的最佳合成条件:m(SL∶)m(中间体)=1∶2.5,相转移催化剂用量为总质量的0.4%,pH=9,55℃反应3 h,产物中的含氮量为2.19%.通过傅里叶变换红外光谱、紫外光谱证实了目标产物结构;并进行接触角和表面张力测试,结果表明,LAS的分散性有明显改善.

Calcium lignosulfonate was sulfonated using sodium bisulfite as sulfonating agent.N-（2,3-ep oxypropyl） hexadecyl dimethyl ammonium chloride intermediate was synthesized by N,N-dimethyl hexadecyl amine and epichlorohydrin.The lignin amphoteric surfactant（LAS） was prepared through hydroxyl alkyation re action by the N-（2,3-epoxypropyl） hexadecyl dimethyl ammonium chloride and sulphonated calcium lignosul phonate（SL） in the presence of tetrabutylammonium bromide catalyst.Through the orthogonal experiment,the optimal sulphonating conditions were determined： 2.0 g of sulfonating agent,reacted at 95 ℃ for 8 h,the relative degree of sulfonation of calcium lignosulfonate was 1.284.The optimal synthesis conditions of LAS were： m（SL）∶m（intermediate）=1∶2.5,the dosage of phase transfer catalyst was 0.4%（on the total mass）,pH=9,reacted at 55 ℃ for 3 h,the N mass fraction of product was 2.19%.The structure of the target product was characterized by FTIR spectrum and UV.The contact angle and surface tension was tested and showed that the dispersion of LAS became better distinctly.