【作者】 义建军；

【导师】 景振华； 许学翔；

【作者基本信息】 石油化工科学研究院 ， 有机化工， 2001， 博士

【摘要】 本文设计并合成了三类新型半茂金属有机配合物，即金属中心分别与一个环戊二烯类配体和一个非环戊二烯类配体作用形成的配合物，其结构通式为LCpTiCl，式中L为含氧或氮原子的非环戊二烯配体。当L分别选择二齿二价阴离子二元芳香酚类配体[O，O]，二齿一价阴离子8-羟基喹啉类配体[O，N]，或氮杂茂配体Np时，半茂配合物分别为[O，O]CpTiCl，[O，N]CpTiCl₂，或NpCpTiCl₂。研究了这三类半茂配合物在助催化剂甲基铝氧烷（MAO）作用下催化乙烯聚合的性能，以及所得聚乙烯的结构特征。 二元芳香酚类配体[O，O]分别为邻苯二酚（C₆H₆O₂）、2，2’-联二苯酚(C₁₂H₁₀O₂)或2,2’-联二萘酚(C₂₀H₁₄O₂)时，可得到三种半茂钛配合物[O，O]CpTiCl；第二类半茂钛配合物[O，N]CpTiCl₂中的配体[O，N]包括8-羟基喹啉（C₉H₇NO）、2-甲基-8-羟基喹啉(C₁₀H₉NO)或5-硝基-8-羟基喹啉（C₉H₆N₂O₃）；第三类半茂钛配合物NpCpTiCl₂中Np分别代表五种氮杂茂配体，即吡咯（Pr），吲哚（Id），7-氮杂吲哚（Ai），吲唑（Iz）和苯并咪唑（Bi）。它们都是由相应配体的阴离子与环戊二烯基三氯化钛（CpTiCl₃）作用形成的，所得配合物由元素分析、红外光谱（IR）及核磁共振（NMR）表征其组成与结构。 研究表明，这三类半茂钛配合物在助催化剂MAO作用下，于30℃、0.1MPa乙烯压力下均可催化乙烯聚合，并显示较高的活性，远高于未引入非茂配体的CpTiCl₃及不含茂环的相应非茂配合物的活性，这说明同时含一个茂配体和一个非茂配体的半茂配合物是烯烃聚合的优良催化剂。此外，半茂体系的催化活性都随铝／钛（Al／Ti）比的增加呈上升而后衰减型，当Al／Ti比为500左右时活性达到最高，这 几类半茂型钛配合物的合成及催化乙烯聚合研究个值远低于茂金属催化剂活性达最高时的AI／T比，即茂金属配合物比半茂配合物需要更多的MAO来活化，并稳定形成的活性中心。 ＊，OX 体系的催化活性依＊，O］配体中芳香环体系的增大而下降，即(C几O＊＞（C；。HsO＊＞（C加；。O小该体系的特点是依制备［O，O厂pT汇1方法的不同，可形成双活性中心或单活性中心：由一步法制备的［O，O］CpT汇1以动力学稳定状态为主，对应所得双峰分布聚乙烯的重均分子量M W为12．5川矿，分子量分布M w／Mn为7．42；由二步法制备的＊，O厂 以热力学稳定状态为主，对应所得单峰分布聚乙烯的分子量较大（Mw节2X‘）且分子量分布较窄（M小h－2补。通过控制制备方法和反应条件，可以实现在同一催化体系中得到双峰分布的聚合产物，这比以往制备双峰分布催化剂的方法，即将两种单活性中心催化剂混合更加简便、高效。 对于＊，州CpT汇1。／MAO体系，配体＊，门中喳啦环上的取代基严重影响着催化活性，当N原子邻位上有给电子基团，如甲基时，［O，州CpTICI，显示较高的活性p．8 XIO’gPE／molTi·h）；而当其苯环上有强吸电子基团，如硝基时，催化活性大大降低。研究结果表明，该体系形成单一活性中心，所得聚乙烯为单峰分布，重均分子量Mw为 40X‘左右，分子量分布较窄叼wAn为 2刀～2．8卜这一体系中聚合反应温度较高时会导致催化活性下降，一定的预反应时间有利于提高催化活性。经计算，［O，门CpT汇l。［MAO体系催化乙烯聚合反应的表观活化能为 引．45kJ／mol，与茂金属催化体系的表观活化能O 9．3 okJ／mol）相当，说明半茂体系与茂金属体系具有相似的反应性。 NpCpTIC12／MAO体系亦形成单活性中。0，催化所得聚乙烯分子量分布较窄（MX／Mn＜），重均分子量 Mw为 3 5 XIO‘左右。该体系的 石油化工科学研究院博士学位论文特点是活性依氮杂茂配体wp的不同而变化，即含一个氮杂原子wp的半茂配合物的催化活性＊0’gPE／molTi个）远高于含两个氮杂原子 Np的半茂配合物的活性＊‘gPE／molTi·h卜 本文采用分子模拟技术，以阿姆斯特丹密度泛函理论（ADF）为基础，首次对＊；OHgNO］CpTIC。和 AIMe。或 MAO中不同助催化点的模型进行量化计算，研究了半茂体系催化乙烯聚合过程中涉及活性中心形成的反应机理。计算由＊；。HgNO］CpTICH厂·AIMe。和不同氯桥或氧桥［C；林NO］CpT汇H。CI·MAO 力 合物形成阳 离子r；OHgNOICpTICH厂所需的能量，证明 MAO 的助催化活性高于AIMev较强酸性铝原子的存在和大阴离子XMAO’（X二CI，Me）对负电荷的有利分散作用是决定较低离解能的重要因素。MAO中含有一定量的A＊e。和单体与金属中心的配位对活性中心的形成起重要作用，一是保护酸性助催化点：二是影响稳定化的［CIOHgNO］CpT汇H3＼－O加合物。此外，在MAO中以中等强度配位的氧原子对金属阳离子活性中心的稳定化起决定作用。 总之，实验及计算结果表明，新型的半茂钛配合物是一类性能优良的烯烃聚合催化剂，不仅能在较温和的条件下保持高的催化活性，而且与助催化剂作用形成的活性中心具有较高的稳定性，需要的助催化剂量远低于茂金属催化剂，可大大?更多还原

【Abstract】 Three types of half-metallocene complexes, in which the metal is coordinated with a cyclopentadienyl and a non-cyclopentadienyl ligands, have been designed and synthesized with the formula LCpTiCl~. L is a non-cyclopentadienyl containing oxygen or mtrogen atoms. When L was biphenols( [0,0]), 8-hydroxy-quinolines( [0,N]), or azoles(Np) separately, the half-metallocene complexes were [0,0]CpTiC1 , [0,N]CpTiC12, or NpCpTiCI2 correspondingly. The catalytic properties of these complexes for ethylene polymerization with activation by Methylalumoxane(MAO) and the structural characters of polyethylene obtained were studied.Three kinds of [0,0]CpTiC1 had been synthesized when [0,0] was catechol(C6H602), 2,2’ -biphenol(C 12H8Oj, or 2,2’ -binaphthol(C2J-11202), respectively, in the case of [0,N]CpTiC12, [0,N] was 8-hydroxyl-quinoline(C9H7NO),2-methyl-8-hydroxyl-quinoline(C1 0H.9N0), and 8-hydroxyl-5 -nitro-quinoline(C9H6N2 03), respectively. There were five kinds of NpCpTiC12, in which Np was pyrolyl(Pr: C4H4N), indolyl(Id:C8H6N); 7-azoindolyl(Ai:C7H5N2), indazolyl(Iz: C7H5N2), and benzimidazolyl(Bi: C7H5N2) respectively. All of them were prepared by the reactions of CpTiCI3 with the anions of the relevant ligands, and characterized by elemental analysis, IR, or NMIR.It was proved that all the LCpTiCl~ was active for ethylene polymerization at 30 0C and 0.1 MPa with activation by MAO, and exhibited much higher activity than CpTiC13. For the LCpTiCl~/MAO system, the catalytic activity followed an "up and down" profile withincrease in the Al/Ti molar ratio, and reached a maximum value when the Al/Ti molar ratio was about 500 which was much lower than that of metallocene system.The results showed that the activity of the (C6H402)CpTiC1JMAO system decreased successively with increase of the aromatic rings in the following order: (C6H402)>(C12H8Oj>(C20H12Oj, and that the polyethylene was characteristic of bi-model distribution with a molecular weight of M~ l2.5x 10~ and a molecular weight distribution of M,JM~ 7.42, or of narrow distribution with M~ of 52.Ox 10~ and M./M~ of 2-3, depending on the synthetic methods of [O,O]CpTiCl. For the [O,N]CpTIC12/MAO system, the activity increased markedly when there was an electron-donor substituent next to N , such as a methyl(2.8 X 1 O5gPE/molTi o h), and decreased significantly when there was an electron-acceptor substituent , such as nitro in the benzene ring; also the active decreased when the polymerization time was too long, and increased when there was a proper pre-reaction time; the polyethylene obtained was characteristic of narrow molecular distribution(MjM~2’-2.8) with MM. of 40x iO~. Besids, the polyethylene obtained by the NpCpTiCL2/MAO system had the same structural properties with MJM~ less than 3 and M.,~, of 35x i0~.Based on the Amsterdan Dense Function(ADF) by Computer Molecular Simulation, the theoretical investigations of reactions between [C101-19N0]CpTiC12 and ALMe3, or different cocatalytic site models of MAO allowed us to reach some significant insights into the mechanismsinvolved in the formation of active species responsible for ethylene polymerization. The energy required to form the [C10H9NO]CpTiCH3~ cation from dissociation of [C10H9N0]CpTiCH3C1 A1Me3 and different kinds of chlorine-bridged and oxygen-bridged [C10H9N0]CpTiCH3C1 MAO model adducts accounted for the higher cocatalytic activity exhibited by MAO with respect to A1Me3. Both the presence of highly acidic aluminum atoms and negative charge dispersion power of XMIAO macroanions (X=Cl,Me) were essential features in determining low dissociation energies. The stabilization of halfmetallocene cations performed by ethylene coordination to titanium, and the A1Me3 content in MAO played an important role in ion-pair separation for affecting active species formation, both protecting the acidic cocatalytic sites as well as affecting the formation of stabilized [C101-{9N0]CpTiCH3--O adducts. Besides, The presence of moderately coordinating oxygen atoms in ~vIAO更多还原