Development and characterization of supported-metal and olefin-polymerization catalysts

催化剂广泛用于生产消费品所需的材料（如塑料、人造纤维、汽油、化肥等）。催化剂通过提供选择性和低能量的途径将原料转化为所需产品，从而提高了原料的利用率。因此，催化剂在绿色化学和提高化学和聚合物生产的可持续性方面发挥着关键作用。催化剂也经常用于消除污染物；这种用途最广为人知的应用是汽车催化转化器。目前提出的研究涉及催化剂的上述两个方面。提出的研究的第一个领域涉及烯烃聚合催化剂的研究。这些研究的目的是深入了解影响聚合物负载茂金属催化剂气相乙烯聚合性能的因素。我们已经开发出各种适合于气相聚合的聚合物负载催化剂，但是决定产物颗粒形状和结构（形态）的因素还不是很清楚。拟议的研究将解决这种缺乏理解的问题。聚合物颗粒的形貌对这些催化剂在流化床反应器中的使用是非常重要的；能够控制形态将允许消除产品的球团化（一个非常能源密集型的步骤），以及为生产专门的微米尺寸，大孔聚乙烯颗粒打开大门。该研究的第二个领域也涉及负载催化剂，但在这种情况下，这些催化剂的应用是通过使用扩散催化反应器完全氧化来消除碳氢化合物污染物。扩散催化反应器取代传统的流动反应器，在石油工业中广泛应用于空间加热。人们对这些装置知之甚少，但它们为通过催化燃烧消除低浓度碳氢化合物提供了巨大的潜力。然而，需要具有更好的抗硫性和更低的结焦倾向的改良催化剂。提出的研究将探索扩散催化反应器的新催化剂配方。

Catalysts are widely used in the production of materials needed for making consumer goods (e.g. plastics, artificial fibres, gasoline, fertilizer, etc.). Catalysts improve the utilization of raw materials by providing selective and low-energy routes for conversion to desired products. Hence, catalysts are a key player in green chemistry and improved sustainability of chemical and polymer production. Catalysts are also frequently used in the elimination of pollutants; the most well know application of this use is the automobile catalytic converter. The currently proposed research addresses both of the above aspects of catalysts. The first area of the proposed research deals with studies on olefin polymerization catalysts. The objective of these studies is to gain insight into the factors which govern the performance of polymer-supported metallocene catalysts for gas-phase ethylene polymerization. We have developed various polymer-supported catalysts which are suitable for gas-phase polymerization, but the factors which determine the shape and structure (morphology) of the product particles are not well understood. The proposed research will address this lack of understanding. The morphology of the polymer particles is very important for the use of these catalysts in fluidized bed reactors; being able to control the morphology will allow the elimination of pelletization of the product (a very energy intensive step), as well as open the door for the production of specialized micron-sized, macro-porous polyethylene particles. The second area of the proposed research also deals with supported catalysts, but in this case the application of these catalysts is in the elimination of hydrocarbon pollutants by complete oxidation using diffusive catalytic reactors. Diffusive catalytic reactors, rather than the conventional flow reactors, are widely used in the petroleum industry for space heating. These devices are poorly understood, but they offer great potential for elimination of hydrocarbons at low concentration by catalytic combustion. However, improved catalysts with better resistance to sulfur and lower tendency for coking are required. The proposed research will explore new catalyst formulations for diffusive catalytic reactors.