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Preparation, Characterization, Catalytic Performance And Copolymerization Process Of The Novel Half Titanocene Catalysts For Ethylene-Propylene Copolymerization

Posted on:2012-06-05Degree:DoctorType:Dissertation
Country:ChinaCandidate:H J ZhangFull Text:PDF
GTID:1221330434476087Subject:Chemical processes
Abstract/Summary:PDF Full Text Request
There are many shortcomings, such as low activity, short polymerization activity center life, highly toxic, deep color of the polymer, or high activity but easy to crystallization to lead to poor performance of the rubber, and so on, for the traditional EPDM vanadium catalyst system or titanium catalyst system. And there are many advantages, such as high polymerization activity, narrow molecular weight distribution, even polymerization units, easy to the molecular design, adaptable to existing processes, and so on, for the metallocene catalyst system.Basing on the relationship between high performance of single-site catalysts and the structure of their ligands, this dissertation study on the synthesis of the metallocene catalysts easily soluble in hexane, including the half titanocene catalysts containing boric acid ester or phosphodiesterase isooctyl groups and aluminum siloxane (AO) cocatalysts, and their catalytic performances. These catalysts, named BTi or PTi, were characterized by elemental analysis and chemical analysis, and were examined on the stability by storage stability test. Catalytic activities of the catalysts were studied by ethylene-propylene copolymerization test, and some more promising catalyst systems for ethylene-propylene copolymerization, such as PTi-8/EBAO and PTi-9/EBAO, were initially screened. Ethylene propylene two-component polymerization process was investigated in detailed using PTi-8/EBAO. Ethylene-propylene four-component polymerization process was investigated in detailed using PTi-9/EBAO catalyst system.Firstly, six kinds of BTi complexes and ten kinds of PTi complexes had been prepared by small molecule removal method, and the structure of them was characterized using elemental analysis and chemical analysis. The introduction of long flexible molecular chains in the single-titanocene molecular made these complexes more easily dissolved in hexane, with a high synthesis conversion rate, a low reaction condition, more likely to industrial production and costing savings.Secondly, five kinds of aluminum siloxane cocatalysts easily dissolved in hexane had been prepared by alkyl aluminum ice-hydrolysis method, and the aluminum and the alkyl contents of them were characterized by chemical analysis and chromatography analysis. The storage stability and catalytic activity were evaluated using the catalytic system with the composition of Zr-1and these AO cocatalysts. The optimum synthesis conditions of the aluminum siloxanes were determined, and the relationship between polymerization degree of the aluminum siloxanes and solubility in hexane was found. The polymerization activity evaluation showed that EBAO is a good cocatalyst for metallocene, can replace expensive MAO.Thirdly, the catalytic performance of BTi and PTi were studied and compared, and the relationship between structure and catalytic properties were analyzed and interpreted, and PTi catalyst as a catalyst for ethylene-propylene copolymer of the study was determined. Application prospects of a variety of PTi catalysts as ethylene-propylene copolymerization catalysts had been carefully analyzed and the result was that PTi-8and PTi-9as catalysts for EPDM rubber were more cost advantage. Detailed studies on catalytic properties of PTi-8and PTi-9had shown that there were many good performances for PTi/EBAO enough to become ideal catalysts of ethylene-propylene random copolymerization in hexane, such as higher catalytic efficiency, heating stable, withdrawing heat easily, larger molecular weight, controlled structure, higher reactivity ratio of propylene, and so on.Fourthly, ethylene-propylene two-component polymerization process was studied in detailed through the synthesis of viscosity index improvers J-0030using PTi-8/EBAO catalyst system. The main control parameters, such as polymerization temperature, polymerization pressure, glue concentration, gas composition, EBAO/PTi-8molar ratio, the amount of PTi-8added, the amount of hydrogen added, were determined. According to the above parameters, continuous polymerization experiments were carried out in2L polymerization mode test plant, and450grams of sample J-0030m was synthesized. Polymer analysis showed that the J-0030m and J-0030in molecular weight, Mooney, polymer composition, aging properties, shear stability, thickening ability, low temperature viscosity, etc. were basically the same. It indicated that the catalyst system PTi-8/EBAO is the better ethylene-propylene two-component random copolymer catalyst system.Finally, ethylene-propylene four-component polymerization process was studied in detailed through the synthesis of long-chain EPDM DSM-8340a using PTi-9/EBAO catalyst system. The main control parameters, such as polymerization temperature, polymerization pressure, glue concentration, gas composition, EBAO/PTi-9molar ratio, the amount of PTi-9added, the amount of hydrogen added, the amount of ENB added, the amount of VNB added, etc., were determined. According to the above parameters, continuous polymerization experiments were carried out in2L polymerization mode test plant, and2000grams of sample J-8340m was synthesized. Polymer analysis showed that the J-8340m and DSM-8340a in polymer composition, vulcanized rubber properties, etc. were basically the same. It indicated that the catalyst system PTi-9/EBAO is the better ethylene-propylene four-component random copolymer catalyst system.
Keywords/Search Tags:single metallocene, titanium compounds, ethylene-propylene copolymerization, catalyst, structuralcharacterization, copolymerization process
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