Foram preparados três tipos de precursores catalíticos homogêneos a base de zirconocênos: os complexos estereorrígidos Et(Ind)2ZrCh 1 e iPrCpFluZrCh 2 contendo simetria C2 e Cs, respectivamente, e o complexo Ind2ZrCh 3. Estes complexos, em presença de metilaluminoxanas (MAO), polimerizam propeno conduzindo a três diferentes tipos de polipropileno. Os complexos estereorrígidos 1 e 2 conduzem a polímeros estereorregulares, iso e sindiotáticos, respectivamente, enquanto o complexo 3 produz polipropileno atático. O grau de estereorregularidade do polímero é dependente da temperatura de polimerização, assim, a baixas temperaturas foram obtidos polímeros altamente estereorregulares, com maiores peso moleculares, Tm eTc. A microestrutura dos polímeros foi determinada por RMN de 13C. / We have carried out three different kinds of homogeneous catalyst based on zirconocenes: stereorigid complexes Et(Ind)2ZrCh 1 ,and iPrCpFluZrCb 2 with symmetry C2 e Cs respectively and the complex Ind2ZrCh 3. These complexes together with methylaluminoxane (MAO) can polymerise propene leading to three different kinds of polypropylene. These stereorigid complexes (1 and 2) lead to stereoregular polymers iso and syndiotatic respectively while the complex 3 lead to atatic polypropylene. The polymer stereorigid degree is related with the polymer temperature thus we have obtained high stereoregular polymers with high molecular weight, Tm and Te. The polymers microstructure were obtained by 13C NMR.

A systematic study of propylene polymerization using a 4th generation Ziegler-Natta catalyst is presented in this thesis. The apparent kinetic rate constants for propylene polymerization were estimated in the presence and absence of hydrogen and/or donor. The estimated activation energies for activation, propagation, and deactivation were found to be close to values previously reported in the literature for similar catalysts. The polypropylene samples were characterized using high-temperature gel permeation chromatography (GPC), carbon-13 nuclear magnetic resonance (13C NMR), and crystallization elution fractionation (CEF). The effect of hydrogen and external electron donor on polypropylene microstructure was investigated at two polymerization temperatures. In addition to the expected electron donor positive effect on tacticity, hydrogen was also found to increase polypropylene tacticity. The effect of changing these polymerization conditions on molecular weight and polydispersity was also investigated. Finally, CEF profiles show how the distribution of polypropylene crystallizability changes by adding hydrogen and electron donor to the reactor. The concentrations of hydrogen and external donor were also varied to study their effect of polymerization kinetics and polymer microstructure. The estimated activation energies were close to those found in the first part of this investigation in the presence and/or absence of donor and hydrogen. A polypropylene microstructural study showed a positive effect of hydrogen concentration on mmmm pentad at low donor concentration, likely due to an increase in stereoselectivity of the aspecific sites by hydrogen. However, increasing donor concentration over a given threshold seems to transform the aspecific sitess into stereospecific sites that are no longer significantly affected by hydrogen. These experimental results were compared to a previously developed Monte Carlo model and found to agree with the trends predicted by simulation. Finally, the effect of diisopropyldimethoxysilane (P), n-propyltrimethoxysilane (N), paraethoxyethylbenzoate (PEEB), and dicyclopentyldimethoxysilane (D) external donors on catalyst activity and stereoselectivity was investigated. P and D donors were more stereoselective than N and PEEB donors; however, D donor had the best activity among all donors investigated. Therefore, D donor was mixed with PEEB to combine its high activity with the self-extinguishing properties of PEEB. The D/PEEB 90/10 (mol/mol) mixture generated a catalyst with good stereoselectivity but poor activity. When the ratio was increased to 95/5 and 98/2, the resulting catalyst had high activity and good stereoselectivity. Interestingly, the D/PEEB combination with just a small fraction of PEEB has a positive effect on the catalysts activation term which may decrease polymerization costs with this system.

The objective of this work is to develop mathematical models to predict molecular weight distributions (MWDs) of ethylene copolymers produced in an industrial gas-phase reactor using a Ziegler-Natta (Z-N) catalyst. Because of the multi-site nature of Z-N catalysts, models of Z-N catalyzed copolymerization tend to be very large and have many parameters that need to be estimated. It is important that the data that are available for parameter estimation be used effectively, and that a suitable balance is achieved between modeling rigour and simplification. In the thesis, deconvolution analysis is used to gain an understanding of how the polymer produced by various types of active sites on the Z-N catalyst responds to changes in the reactor operating conditions. This analysis reveals which reactions are important in determining the MWD and also shows that some types of active sites share similar behavior and can therefore share some kinetic parameters. With this knowledge, a simplified model is developed to predict MWDs of ethylene/hexene copolymers produced at 90 °C. Estimates of the parameters in this isothermal model provide good initial guesses for parameter estimation in a subsequent more complex model. The isothermal model is extended to account for the effects of butene and temperature. Estimability analysis and cross-validation are used to determine which parameters should be estimated from the available industrial data set. Twenty model parameters are estimated so that the model provides good predictions of MWD and comonomer incorporation. Finally, D-, A-,and V-optimal experimental designs for improving the quality of the model predictions are determined. Difficulties with local minima are addressed and a comparison of the optimality criteria is presented. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2009-05-28 20:43:58.37

A systematic study of propylene polymerization using a 4th generation Ziegler-Natta catalyst is presented in this thesis. The apparent kinetic rate constants for propylene polymerization were estimated in the presence and absence of hydrogen and/or donor. The estimated activation energies for activation, propagation, and deactivation were found to be close to values previously reported in the literature for similar catalysts. The polypropylene samples were characterized using high-temperature gel permeation chromatography (GPC), carbon-13 nuclear magnetic resonance (13C NMR), and crystallization elution fractionation (CEF). The effect of hydrogen and external electron donor on polypropylene microstructure was investigated at two polymerization temperatures. In addition to the expected electron donor positive effect on tacticity, hydrogen was also found to increase polypropylene tacticity. The effect of changing these polymerization conditions on molecular weight and polydispersity was also investigated. Finally, CEF profiles show how the distribution of polypropylene crystallizability changes by adding hydrogen and electron donor to the reactor. The concentrations of hydrogen and external donor were also varied to study their effect of polymerization kinetics and polymer microstructure. The estimated activation energies were close to those found in the first part of this investigation in the presence and/or absence of donor and hydrogen. A polypropylene microstructural study showed a positive effect of hydrogen concentration on mmmm pentad at low donor concentration, likely due to an increase in stereoselectivity of the aspecific sites by hydrogen. However, increasing donor concentration over a given threshold seems to transform the aspecific sitess into stereospecific sites that are no longer significantly affected by hydrogen. These experimental results were compared to a previously developed Monte Carlo model and found to agree with the trends predicted by simulation. Finally, the effect of diisopropyldimethoxysilane (P), n-propyltrimethoxysilane (N), paraethoxyethylbenzoate (PEEB), and dicyclopentyldimethoxysilane (D) external donors on catalyst activity and stereoselectivity was investigated. P and D donors were more stereoselective than N and PEEB donors; however, D donor had the best activity among all donors investigated. Therefore, D donor was mixed with PEEB to combine its high activity with the self-extinguishing properties of PEEB. The D/PEEB 90/10 (mol/mol) mixture generated a catalyst with good stereoselectivity but poor activity. When the ratio was increased to 95/5 and 98/2, the resulting catalyst had high activity and good stereoselectivity. Interestingly, the D/PEEB combination with just a small fraction of PEEB has a positive effect on the catalysts activation term which may decrease polymerization costs with this system.

Techn. Universiẗat, Diss., 2003--Berlin.

Universiẗat, Diss., 2004--Düsseldorf.

Universiẗat, Diss., 2004--Düsseldorf.

Foram preparados três tipos de precursores catalíticos homogêneos a base de zirconocênos: os complexos estereorrígidos Et(Ind)2ZrCh 1 e iPrCpFluZrCh 2 contendo simetria C2 e Cs, respectivamente, e o complexo Ind2ZrCh 3. Estes complexos, em presença de metilaluminoxanas (MAO), polimerizam propeno conduzindo a três diferentes tipos de polipropileno. Os complexos estereorrígidos 1 e 2 conduzem a polímeros estereorregulares, iso e sindiotáticos, respectivamente, enquanto o complexo 3 produz polipropileno atático. O grau de estereorregularidade do polímero é dependente da temperatura de polimerização, assim, a baixas temperaturas foram obtidos polímeros altamente estereorregulares, com maiores peso moleculares, Tm eTc. A microestrutura dos polímeros foi determinada por RMN de 13C. / We have carried out three different kinds of homogeneous catalyst based on zirconocenes: stereorigid complexes Et(Ind)2ZrCh 1 ,and iPrCpFluZrCb 2 with symmetry C2 e Cs respectively and the complex Ind2ZrCh 3. These complexes together with methylaluminoxane (MAO) can polymerise propene leading to three different kinds of polypropylene. These stereorigid complexes (1 and 2) lead to stereoregular polymers iso and syndiotatic respectively while the complex 3 lead to atatic polypropylene. The polymer stereorigid degree is related with the polymer temperature thus we have obtained high stereoregular polymers with high molecular weight, Tm and Te. The polymers microstructure were obtained by 13C NMR.

Foram preparados três tipos de precursores catalíticos homogêneos a base de zirconocênos: os complexos estereorrígidos Et(Ind)2ZrCh 1 e iPrCpFluZrCh 2 contendo simetria C2 e Cs, respectivamente, e o complexo Ind2ZrCh 3. Estes complexos, em presença de metilaluminoxanas (MAO), polimerizam propeno conduzindo a três diferentes tipos de polipropileno. Os complexos estereorrígidos 1 e 2 conduzem a polímeros estereorregulares, iso e sindiotáticos, respectivamente, enquanto o complexo 3 produz polipropileno atático. O grau de estereorregularidade do polímero é dependente da temperatura de polimerização, assim, a baixas temperaturas foram obtidos polímeros altamente estereorregulares, com maiores peso moleculares, Tm eTc. A microestrutura dos polímeros foi determinada por RMN de 13C. / We have carried out three different kinds of homogeneous catalyst based on zirconocenes: stereorigid complexes Et(Ind)2ZrCh 1 ,and iPrCpFluZrCb 2 with symmetry C2 e Cs respectively and the complex Ind2ZrCh 3. These complexes together with methylaluminoxane (MAO) can polymerise propene leading to three different kinds of polypropylene. These stereorigid complexes (1 and 2) lead to stereoregular polymers iso and syndiotatic respectively while the complex 3 lead to atatic polypropylene. The polymer stereorigid degree is related with the polymer temperature thus we have obtained high stereoregular polymers with high molecular weight, Tm and Te. The polymers microstructure were obtained by 13C NMR.

Cílem této práce bylo prostudovat vliv předpolymerace na vybraný komerční MgCl2–nosičový TiCl4 katalyzátor (tzv. Zieglerův-Nattův). Výsledkem práce bylo nalezení optimálních podmínek, které umožní ideálně využít této techniky k modifikaci struktury a morfologie zvoleného katalyzátoru a dosažení stabilnějšího průběhu polymerace a lepších vlastností produkovaného polypropenu. U předpolymerací byl studován vliv teploty, koncentrace triethylhliníkového kokatalyzátoru a externího donoru, množství polyolefinu syntetizovaného během předpolymerace (tzv. stupeň předpolymerace) na následné chování předpolymerovaného katalyzátoru při plynofázní polymeraci propenu.