松香酯O-烷基化改性增强木质素胺表面活性

Surface Activity of a Novel Lignin-amine Surfactant Reinforced by Rosin Ester via O-Alkylation Reaction

以碱木质素为原料,通过与二乙烯三胺和甲醛的Mannich反应得到了木质素胺,再通过和松香与环氧氯丙烷的酯化产物(3-松香酰氧-2-羟丙基氯,简称为松香酯)的O-烷基化反应引入亲油性的松香酯基团,合成了松香改性木质素胺表面活性剂,并通过红外、紫外、表面张力仪对目标产物的结构和性能进行了测定。结果表明,合成松香酯的适宜条件为n(环氧氯丙烷)∶n(松香)=1.5∶1.0、反应温度100℃、反应时间6 h。在该条件下,松香的酯化率为95.6%。按n(木质素胺)∶n(松香酯)=4∶1合成的目标产物在pH=2的稀盐酸中,当其质量浓度为10 g/L时,表面张力为33.2 mN/m,当其质量浓度为5 g/L时,甲苯乳液分层时间为73 min;而同样条件下木质素胺的表面张力为48.5 mN/m,甲苯乳液分层时间为43 min,引入松香酯基团可以增强木质素胺表面活性。

Lignin-amine was prepared by a Mannich reaction of alkali lignin with diethylenetriamine and formaldehyde, then lignin-amine was modified by rosin ester synthesized from epiehlorohydrin. The surfactant was characterized by IR, UV and the automatic surface tensiometer, and its physico-ehemical properties were also measured. The introduction of abietyl groups as hydrophobic groups in lignin- amine,by O-alkylation reaction, enhanced the performance of the surfactant. The experiment results showed that the synthesis conditions for rosin ester were optimized as follows ： the molar ratio of rosin to epichlorohydrin was 1：1.5, reaction temperature was 100 ℃, reaction time was 6 h. Under these conditions, the conversion rate of rosin was up to 95.6%. When the molar ratio of lignin-amine to rosin ester was 4：1 ,the surface tension of the surfactant reached 33.2 mN/m at a mass concentration of 10 g/L hydrochloric acid aqueous solution with a pH 2.0. The emulsifiability of the surfactant was 73 min at a mass concentration of 5 g/L. In contrast, the surface tension of lignin-amine at the same condition was 48.5 mN/m, and it＇s emulsifiability was 43 min. As expected, the performance of the surfactant was improved by abietyl groups.