| 학회 | 한국고분자학회 |
| 학술대회 | 2004년 가을 (10/08 ~ 10/09, 경북대학교) |
| 권호 | 29권 2호, p.171 |
| 발표분야 | 고분자 합성 |
| 제목 | A Density Functional Study on the Mechanism of Stereoselectivity in Heterogeneous Ziegler-Natta Catalytic System |
| 초록 | We have investigated the mechanism of stereoselectivity in the propene polymerization with MgCl2-supported heterogeneous Ziegler-Natta catalyst by means of a density functional theory(DFT). Two different model surfaces of MgCl2 cluster onto which a Ti2Cl6 is adsorbed are examined as the active sites of the Ziegler-Natta catalytic system: (110) surface and (100) surface1,2. The reaction pathway of propene insertion into the active sites having 2,4-dimethyl pentane as a growing polymer chain was studied by using geometry optimization and transition state search. It is found that the growing chain is rotated due to the sterically repulsive interaction between the chain and Cl ligand. In particular, at the transition state, it is energetically more favorable when the second carbon atom of the growing chain and the methyl group of propene are located on the opposite side of the plane defined by the double bond of inserting monomer and the metal atom than when they are on the same side of the plane. These results indicate that the sterically repulsive interaction between the growing chain and Cl ligand responsible for the orientation of growing chain gives rise to the discrimination between the prochiral faces of the monomer. Fig. 1. π-complex structures on (100) sufrace(left) and (110) surface(right). 참고문헌 1. G. Monaco, M. Toto, G. Guerra, P. Corradini, and L. Cavallo, Macromolecules, 33, 8953 (2000). 2. P. Corradini, G Guerra, and L. Cavallo, Acc. Chem. Res., 37, 231 (2004) |
| 저자 | 이진우, 양성훈, 허준, 조원호 |
| 소속 | 서울대 |
| 키워드 | ziegler-natta; propene polymerization; dft; density functional |
