核磁共振技术对析出型催化剂溶解过程的研究

Study on dissolution process of precipitate-type catalysts by nuclear magnetic resonance technology

采用液体NMR技术,研究了聚乙烯用溶解析出体系催化剂溶解过程及给电子体与MgCl_(2)的配位状态。实验结果表明,在给电子体和MgCl_(2)等摩尔比条件下,环氧氯丙烷(ECP)和乙醇(EtOH)由于分子极性较强难以溶解MgCl_(2),而磷酸三丁酯(TBP)由于具有非极性的烷基链结构可使MgCl_(2)部分溶解于甲苯;ECP和TBP两者共同溶解MgCl_(2)时可形成完全溶于甲苯的MgCl_(2)-ECP-TBP共同络合物;ECP,TBP,EtOH共同溶解MgCl_(2)时,MgCl_(2)与TBP和EtOH迅速配位,部分溶于甲苯中,ECP则随着反应进行逐渐开环进入到溶液相中,推测最后形成MgCl_(2)-ECP-TBP-EtOH共同配合物,完成溶解。

The dissolution process of polyethylene dissolution and precipitation system catalyst and the coordination state of the electron donors and MgCl_(2) have been studied by liquid NMR.The results show that under the condition of an equal molar ratio of electron donor and MgCl_(2),epichlorohydrin(ECP)and ethanol(EtOH)are difficult to dissolve MgCl_(2) because of their strong molecular polarity,while tributyl phosphate(TBP)can partially dissolve MgCl_(2) in toluene due to its non-polar alkyl chain structure.When ECP and TBP dissolve MgCl_(2) together,forming MgCl_(2)-ECP-TBP co-complex which is completely soluble in the solvent.When ECP,TBP and ethanol co-dissolve MgCl_(2),MgCl_(2) rapidly coordinate with TBP and ethanol and partially dissolve in toluene.ECP gradually opens the ring and enters the solution phase as the reaction proceeds.We assume that it will finally form the MgCl_(2)-ECP-TBP-EtOH co-complex and complete the dissolution.