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通过氯化镧与Schiff碱钠盐(NaSalen)的交换反应制备了4种镧的Schiff碱配合物La(HSalen1～4)3,对其中以3,5-二叔丁基水杨醛缩苯胺为配体的配合物La(HSalen2)3进行了X-射线单晶衍射分析,测定其单晶结构为五角双锥构型,七配位的镧金属中心与氮和氧原子相连.将所得的La(HSalen)3配合物作为单组份催化剂用于催化烷基异氰酸酯聚合,发现以水杨醛缩苯胺为配体的配合物La(HSalen1)3的催化活性最高.深入研究了配合物La(HSalen1)3催化的己基异氰酸酯(HIC)的聚合,详细考察了催化剂用量、单体浓度、聚合时间和温度以及聚合溶剂等对单体转化率、产物分子量及分子量分布的影响.研究结果表明,在-40～20℃温度范围内,配合物La(HSalen1)3均可以催化己基异氰酸酯聚合,得到黏均分子量10×104～50×104之间的聚己基异氰酸酯(PHIC),由于存在解聚反应,提高聚合温度和延长聚合反应时间均导致聚合物分子量降低,分布变宽.适宜的聚合条件为:[HIC]=3.43 mol/L,[La]=8.58×10-3 mol/L,-40℃甲苯溶液中聚合12 h,得到的聚合物产率75.5%,Mv=35.4×104,MWD=3.86.
Four kinds of lanthanum Schiff base complexes La (HSalen1 ~ 4) 3 were prepared by the exchange reaction of lanthanum chloride with NaSalen, and the reaction of 3,5-di-tert-butylsalicylaldehyde aniline with The ligand complex La (HSalen2) 3 was characterized by single crystal X-ray diffraction analysis and its single crystal structure was determined to be pentagonal bipyramidal. The seven-coordinated lanthanum metal center was connected to nitrogen and oxygen atoms. The obtained La (HSalen1) 3, a complex of salicylaldehyde aniline, was found to be the most effective catalyst for the catalyzed polymerization of alkyl isocyanate with one-component HSalen 3 complex as a one-component catalyst. ) 3 catalyzed polymerization of hexyl isocyanate (HIC) was investigated in detail, and the effect of catalyst concentration, monomer concentration, polymerization time and temperature, and polymerization solvent on the monomer conversion, product molecular weight and molecular weight distribution were investigated in detail. In the temperature range of 40 ~ 20 ℃, the complex La (HSalen1) 3 can catalyze the polymerization of hexyl isocyanate to get polyhexyl isocyanate (PHIC) with the molecular weight of 10 × 104 ~ 50 × 104. Due to depolymerization reaction, Polymerization temperature and prolonged polymerization time lead to polymerization The molecular weight decreased and the distribution broadened.The suitable polymerization conditions were: [HIC] = 3.43 mol / L, [La] = 8.58 × 10-3 mol / L, polymerization in toluene at -40 ℃ for 12 h, yield of polymer 75.5%, Mv = 35.4x104, MWD = 3.86.