聚对苯乙烯磺酸微球的绿色制备及催化合成生物柴油

Green Preparation of Poly (p-phenylene sulfonic acid) Microspheres and Catalytic Synthesis of Biodiesel

摘要:

通过简单、绿色、可控的方法制备了聚对苯乙烯磺酸微球，并将其作为固体酸催化剂用于催化合成生物柴油。首先，以水为介质、苯乙烯（St）为基体单体、二乙烯苯（DVB）为交联单体、对苯乙烯磺酸钠（NaSS）为功能单体、甲基丙烯酸（MAA）为水溶性单体、过硫酸钾（KPS）为引发剂，采用无皂乳液聚合法制备了聚对苯乙烯磺酸微球（PSS）。利用FT-IR、XPS、SEM、TGA和DSC对其进行表征与测试，并对其粒径、zeta电位、比表面积、酸密度进行了考察，探讨了NaSS、DVB和KPS等原料用量对PSS结构、性能的影响。然后，将PSS作为固体酸催化剂，用于催化油酸/甲醇酯化合成生物柴油；结果表明，当甲醇/油酸的物质的量比为10:1、PSS用量为油酸质量的2 %、反应温度为80 ℃、反应时间为6 h时，油酸的转化率可达86.4%。PSS作为固体酸催化剂具有较好的重复使用性能，循环使用4次后油酸转化率没有明显下降。

Abstract:

Poly(p-phenylene sulfonic acid) microspheres were prepared by a simple, green and controllable method, and used as solid acid catalysts for the synthesis of biodiesel. Firstly, poly (p-phenylene sulfonic acid) microspheres (PSS) were prepared by soap-free emulsion polymerization with water as medium, styrene (St) as the matrix monomer, divinylbenzene (DVB) as the cross-linking monomer, sodium p-phenylene sulfonate (NaSS) as functional monomer, methacrylic acid (MAA) as the water-soluble monomer, and potassium persulfate (KPS) as the initiator. The obtained microspheres were characterized by FT-IR, XPS, SEM, TGA and DSC, and their particle size, zeta potential, specific surface area and acid density were investigated. The effects of NaSS, DVB and KPS contents on the structure and properties of the microspheres were discussed. Then, PSS was used as solid acid catalyst to catalyze the esterification of oleic acid/methanol to synthesize biodiesel. The conversion rate of oleic acid could reach 86.4% when the ratio of methanol to oleic acid is 10:1, the amount of PSS is 2% of the mass of oleic acid, the reaction temperature is 80 ℃, and the reaction time is 6 h. As a solid acid catalyst, PSS has good reusability, and the conversion of oleic acid has not decreased significantly after 4 cycles.