【作者】 张宝军；

【导师】 王延吉；

【作者基本信息】 河北工业大学 ， 化学工艺， 2007， 博士

【摘要】 α-烯烃(1-己烯、1-辛烯等)是重要的化工原料。乙烯齐聚法生产α-烯烃工艺的关键在于新型高效催化剂的开发。本文基于电子效应和空间位阻效应理论,对镍系、铁系、三元铬系、四元铬系及负载型铬系等乙烯齐聚催化剂的制备及反应性能进行了较系统的研究。镍系催化剂:首先设计并合成了5个系列15个新型乙酰吡啶基镍络合物,研究了主催化剂配体苯胺的邻位取代基位阻、邻对位取代基种类、间位取代基种类、烷基取代基种类、取代基位置、单双取代基等对乙烯齐聚催化反应性能的影响规律。发现氯化2-乙酰基-6-(2-甲基苯亚胺基)乙基吡啶镍络合物催化剂具有较高的催化活性和α-烯烃选择性;然后,针对该催化剂配体的合成,考察了温度、催化剂及反应时间等因素对配体收率的影响,确定了优化的合成条件;最后,考察了反应温度、反应压力、Al/Ni物质的量比、Ni的浓度及反应时间等对催化活性和α-烯烃选择性的影响。在反应温度为60℃、反应压力为2.0 MPa、Al/Ni物质的量比为1500、Ni的浓度为20μmol/L、反应时间为30 min的条件下催化乙烯齐聚反应,催化活性为1.95×107 g/(mol Ni?h),1-己烯选择性为20.0 wt%,1-辛烯选择性为19.1 wt%。铁系催化剂:设计并合成了氯化2-乙酰基-6-(2-甲基苯亚胺基)乙基吡啶铁络合物,考察了反应温度、Al/Fe物质的量比、反应压力等对催化活性和α-烯烃选择性的影响。在反应温度为60℃、反应压力为4.0 MPa、反应时间为30 min、Al/Fe物质的量比为1500、Fe浓度为20μmol/L的条件下催化乙烯齐聚反应,催化活性为2.70×107 g/(mol Fe?h),1-己烯选择性为20.6 wt%,1-辛烯选择性为18.5 wt%。三元铬系催化剂:设计并合成了12个新型P∩N∩P / P∩N∩R∩N∩P型配体,分别与乙酰丙酮铬、MAO(甲基铝氧烷)组成三元催化剂,催化乙烯齐聚高选择性合成1-辛烯,研究了配体的空间位阻效应和电子效应对乙烯齐聚反应性能的影响。发现由P∩N∩R∩N∩P型配体j、k、l组成的催化剂具有较高的催化活性和1-辛烯选择性;考察了反应温度、Al/Cr物质的量比及反应压力等对催化活性和1-辛烯选择性的影响。在Cr浓度为190μmol/L,Al/配体l/Cr物质的量比为350/2/1,反应时间为30 min,反应温度为50℃,反应压力为4.0 MPa的条件下,催化活性为3.42×106 g/(mol Cr?h),1-辛烯的选择性为73.3 wt%。四元铬系催化剂:为了进一步提高1-辛烯的选择性,在三元铬系催化剂(乙酰丙酮铬、配体l、助催化剂)中加入促进剂组分构成四元铬系催化剂,考察了促进剂、助催化剂、配体/Cr物质的量比、Al/Cr物质的量比、反应温度、反应压力等对乙烯齐聚反应性能的影响。发现以六氯乙烷为促进剂、MAO为助催化剂时,该催化剂具有较高的催化活性和1-辛烯选择性。在Cr浓度为100μmol/L, Cr/配体l/Al/六氯乙烷物质的量比为1/1/300/1.5,反应时间为30 min,反应温度为50℃,反应压力为5.0 MPa的条件下,催化活性为4.5×106g/(mol Cr?h),1-辛烯选择性为79.3 wt%。负载型四元铬系催化剂:为了避免生成的聚乙烯粘釜,降低助催化剂的用量,将四元均相催化剂负载于经MAO处理过的SiO2上,制备出负载型四元铬系催化剂。然后对负载型催化剂进行了表征,系统考察了制备条件等对载Cr量和载Al量的影响,推测出铬系催化剂的负载机理。接着,又考察了工艺条件对负载型催化剂的活性和1-辛烯选择性的影响,并进行了反应动力学研究;最后,对合成的聚乙烯进行了分析表征,考察了工艺条件等对聚乙烯分子量及分子量分布的影响,对聚乙烯进行了热性能分析,比较了均相催化剂和负载型催化剂得到的聚乙烯的表观形态。在Cr浓度为480μmol/L,Cr/配体l/Al/六氯乙烷物质的量比为1/1/100/1.5,反应时间为60 min,反应温度为40℃,反应压力为4.0 MPa的条件下催化乙烯齐聚反应,催化活性为1.9×106 g/(molCr?h),1-辛烯选择性为81.4%;四元铬系催化剂的负载化有效地改善了所得聚乙烯的表观形态,得到了致密的且复制了载体形态的聚乙烯颗粒。更多还原

【Abstract】 α-olefins such as 1-hexene and 1-octene are important chemical feedstocks, and the key to producing it via ethylene oligomerization is the development of the high effective catalysts. In this paper, a series of nickel, iron, trinal and quadplex chromium, supported chromium-based complexes were synthesized and systemic investigated.Nickel-based catalysts: First of all, five kinds amount to fifteen acetyl pyridy nickel-based complexes were synthesized, and the influences of the steric bulk of ortho-substituents, the variety of ortho-substituents, p-substituents, m-substituents, alkyl-substituents and single or double substituents on the catalytic performance were studied in the presence of aniline ligand. The results show that 2-acetyl-6(2-methyl phenyl imino)ethyl pyridyl nickel-based complexes exhibited higher catalytic activity andα-olefins selectivity. In addition, the reaction temperature, catalyst and reaction time were studied and optimized on the productivity of ligand. Finally, various reaction parameters such as reaction temperature, reaction pressure, molar ratio of aluminum to nickel, the concentration of precatalyst and reaction time on the catalytic activity and the selectivity ofα-olefin were investigated. Under the conditions of 60℃, 2.0 MPa, 30 minute, the molar ratio of aluminum to nickel of 1500 and the concentration of nickel of 20μmol/L, the catalyst gives a high catalytic activity of 1.95×107 g/mol Ni?h, a selectivity of 1-hexene up to 20.0 wt% and 1-octene 19.1 wt%.Iron-based catalysts: Chloro-2-acetyl-6(2-methyl phenyl imino)ethyl pyridyl ironl-based complexes were synthesized. The effects of reaction temperature, molar ratio of aluminum to iron and reaction pressure on the catalytic activity and the selectivity ofα-olefin were investigated. Under the condition of 60℃, 4.0 MPa,30 minute, the molar ratio of aluminum to iron of 1500 and the concentration of iron of 20μmol/L. The catalyst system yields 1-octene in selectivity up to 18.5 wt%, 1-hexene up to 20.6 wt%, catalytic activity in excess of 2.70×107 g/mol Fe?h could be achieved.Trinal chromium-based catalysts: Twelve P∩N∩P / P∩N∩R∩N∩P ligands were synthesized. Ethylene oligomerization was carried out in the presence of ligands, Cr(acac)3 and MAO, and the effects of steric bulk of ligands were also studied. The results reveal that the catalyst system with j, k, l ligands show high catalytic activity and 1-octene selectivity. Subsequently, the effects of reaction temperature, molar ratio of aluminum to chromium and reaction pressure on the catalytic activity and the selectivity of 1-octene were investigated. Under the condition of chromium of 190μmol/L, the molar ratio of aluminum to ligand to chromium of 350: 2:1, 30 minute, 50℃and 4.0MPa, the catalytic activity is 3.42×106g/mol Cr?h, the selectivity of 1-octene is 73.3 wt%.Quadplex chromium-based catalysts: In order to improve the selectivity of 1-octene, an accelerant was added into the catalyst system which is composed of Cr(acac)3, ligand 1 and cocatalyst, and the effects of accelerant, cocatalyst, molar ratio of ligand to chromium, molar ratio of aluminum to chromium, reaction temperature and reaction pressure were investigated. The results demonstrate that an increased activity and 1-octene selectivity were observed in the presence of hexachloroethane and MAO. Under the condition of chromium of 100μmol/L, molar ratio of chromium to ligand to MAO to hexachloroethane of 1:1:300:1.5, 30min, 50℃and 5.0 MPa, the catalytic activity is 4.5×106 g/mol Cr?h, the selectivity of 1-octene is 79.3 wt%. Quadplex chromium-based complexes supported on SiO2: In order to prevent the polymer from pasting on the reactor and reduce the amount of the cocatalyst, quadplex chromium-based complexes supported on SiO2 which was modified by MAO were prepared and characterized. Upon the effects of reaction condition on supported amount of chromium and aluminum, we supposed the mechanism of supporting. Furthermore, reaction parameters were studied, as well as the kinetics. Finally, comparing with homogeneous catalysts, the polymer by-products were characterized by thermal analysis, as well as the molecular weight and molecular distribution. Under the condition of chromium of 480μmol/L, molar ratio of chromium to ligand to MAO to hexachloroethane of 1:1:100:1.5, 30 minute, 40℃and 4.0 MPa, the catalytic activity is up to 1.9×106 g/mol Cr?h, the selectivity of 1-octene is 81.4 wt%. The results show that the apparent configuration of the polymers were remarkably improved by using the homogeneous catalysts supported on SiO2. Moreover, the compact polyethylene, the configuration of which is similar to SiO2 was obtained.更多还原