摘要
考察了复合催化剂ＡｌＣｌ_３／ＳｂＣｌ_３的不同配制方法和质子捕捉剂２，６－二异丁基－４－甲基吡啶（ＤＴＢＭＰ）对α－蒎烯阳离子聚合反应的影响。结果表明，ＡｌＣｌ_３和ＳｂＣｌ_３加热熔融复合比简单复合的引发聚合活性更高；ＤＴＢＭＰ对该复合催化剂的聚合反应速率及其产物分子量分布均无明显影响，证明该复合催化剂形成的活性种本质上与质子Ｈ活性种不同，是新型活性种。根据２７ＡｌＮＭＲ对该体系活性种分析结果，认为引发阳离子是［Ｓｂ（Ｖ）Ｃｌ_４］，抗衡阴离子是［Ａｌ_２Ｃｌ_７］
The effects of the preparation methods of the AlCl3/SbCl3 binary catalyst and the proton trap 2,6-ditert-butyl-4-methyl pyridine(DTBMP)on the cationic polymerization of apinene were investigated respectively.The results showed that, if AlCl3 and SbCl3 were melted to form the combined catalyst,its initiating activity was higher than that of the catalyst obtained by simply mixing of AlCl3 and SbCl3.α-Pinene was hardly initiated by the simple combination of AlCl3 and SbCl3 at-78℃,howeve,the melted binary catalyst system led to a fast polymerization even at such a low temperature,The proton trap DTBMP had no obvious effects on the AlCl3/SbCl3 catalyzed polymerization in term of the rate and the molecular weight distribution.These results indicated that new initiating species which was different from protonic species H in nature was generated by the reaction of AlCl3 and SbCl3.Furthermore,the reaction of AlCl3 and SbCl3 was examined by 27 Al NMR spectrum. No signal was observed in the 27 Al NMR spectrum of AlCl3 alone system because of its poor solubility in the used solvent (toluene), but there appeared a strong absorption in the spectrum of AlCl3/ SbCl3 binary system,and the chemical shifts unchanged before and after the polymerization. These show that a new Al-containing compound, soluble in toluene,was generated by AlCl 3 and SbCl3 to initiate the polymerization,and that the metal atom adding to the monomer is not Al but Sb in the initiating reaction.The proposed initiating cation was[SbCl_4],and the counter anion was[Al_2Cl_7] .
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1996年第8期1314-1318,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
广东省科学基金
