Salen-Ni配合物催化合成聚甲基丙烯酸十二酯降凝剂

以甲基丙烯酸十二酯为原料、不对称Salen-Ni-Salicylaldehyde配合物/偶氮二异丁腈(AIBN)为催化体系，在甲苯溶剂中，通过溶液聚合，在Schlenk装置上合成了聚甲基丙烯酸十二酯(PLMA)。采用红外光谱、核磁共振氢谱表征了聚甲基丙烯酸十二酯的结构，利用凝胶渗透色谱(GPC)测定了聚合物的相对分子质量及其分布，并对其降凝性能进行了评价。结果表明：当助催化剂(偶氮二异丁腈(AIBN))与催化剂(Salen-Ni-Salicylaldehyde)的摩尔比为3∶1反应温度为110 ℃、反应时间为8 h、单体与催化剂的摩尔比为2400∶1时，催化剂的活性为4.087 ×10⁴ g/(mol·h)。合成的聚合物数均相对分子质量范围为2.563×10⁴~10.527×10⁴。当油品中PLMA加剂量为1.5%(质量分数)时，可将300~340 ℃柴油馏分和380~400 ℃润滑油馏分的凝点分别降低5~10 ℃和2~6 ℃。当300~340 ℃柴油馏分中添加2.0%(质量分数)的PLMA降凝剂时，凝点可降低12 ℃，降凝效果较好。

Preparation of Pour Point Depressant Poly (Lauryl Methacrylate) With Salen-Ni Complex Catalyst

Poly(lauryl methacrylate)(PLMA) was synthesized with a symmetric Salen-Ni-Salicylalde hyde complex/azodiisobutyronitrile (AIBN) catalyst system by solution polymerization in toluene through Schlenk device. The structure of PLMA was further characterized by FT-IR and ¹H NMR techniques. Meanwhile, the relative molecular mass and its distribution of PLMA polymer were determined by gel permeation chromatography (GPC). Performance of the synthesized pour point dispressant was also evaluated. Experimental results show that the optimum synthetic reactions conditions are: molar ratio of co-catalyst(AIBN) and catalyst (Salen-Ni-Salicylaldehyde) 3∶1, reaction temperature of 110 ℃, reaction time 8 h, ratio of monomer and catalyst 2400∶1.Under the above conditions, the catalyst activity can be 4.087 ×10⁴ g/(mol·h). Relative molecular mass of the polymer is in the range of 2.563×10⁴ to 10.527×10⁴. When 1.5% PLMA was added to diesel fraction (300-340 ℃) and lubricant fraction (380-400 ℃), pour point of the diesel and lubricant could decrease 5-10 ℃ and 2-6 ℃, respectively. When 2.0% PLMA was added to the diesel fraction (300-340 ℃), pour point of the diesel could decrease 12 ℃ and the additive demonstrated very good performance.