A theoretical investigation of the binding of TiCln to MgCl2

被引:35
作者
Martinsky, C
Minot, C
Ricart, JM
机构
[1] Univ Paris 06, Chim Theor Lab, UMR 7616, CNRS, F-75252 Paris 5, France
[2] Univ Rovira & Virgili, Dept Quim Fis, Tarragona 43005, Spain
[3] Univ Rovira & Virgili, Inst Estudis Avancats, Tarragona 43005, Spain
关键词
computer simulations; molecular dynamics; density functional calculations; halides; catalysis; chemisorption;
D O I
10.1016/S0039-6028(01)01373-5
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The structure of the (0 0 0 1) surface of the alpha -MgCl(2) crystal has been investigated using DFT-GGA periodic calculations. The calculated surface relaxation is in agreement with LEED measurements. Motivated for the use of MgCl(2) as support for the Ziegler-Natta reaction, we have studied the adsorption of the catalyst (titanium chlorides as monomers or dimers) on the (1 0 0) and (1 1 0) MgCl(2) surfaces. The structures of adsorbed species are close to those previously found on cluster models: bridging chlorine atoms connect the Ti to the Mg atoms and the systems remain in high spin states. The (0 0 0 1) surface is the most stable face of the alpha -MgCl(2) crystal; however it is Cl-terminated and henceforth poorly reactive; it had been suggested to deposit metallic Mg in order to improve its reactivity. Our modelling explains the failure of this tentative; the interaction between the deposited metal and the surface is repulsive and uncharged Mg atom does not bind. (C) 2001 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:237 / 250
页数:14
相关论文
共 41 条
[1]   First principles study of propene polymerization in Ziegler-Natta heterogeneous catalysis [J].
Boero, M ;
Parrinello, M ;
Hüffer, S ;
Weiss, H .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (03) :501-509
[3]  
BUTAKOV GD, 1995, REACT KINET CATAL LE, V9, P1751
[4]   MAGNESIUM-CHLORIDE SUPPORTED HIGH MILEAGE CATALYSTS FOR OLEFIN POLYMERIZATION .12. POLYMERIZATION OF ETHYLENE [J].
CHIEN, JCW ;
BRES, PL .
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 1986, 24 (10) :2483-2505
[5]   MAGNESIUM-CHLORIDE-SUPPORTED HIGH-MILEAGE CATALYSTS FOR OLEFIN POLYMERIZATION .3. ELECTRON-PARAMAGNETIC RESONANCE STUDIES [J].
CHIEN, JCW ;
WU, JC .
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 1982, 20 (09) :2461-2476
[6]   MAGNESIUM-CHLORIDE SUPPORTED HIGH-MILEAGE CATALYSTS FOR OLEFIN POLYMERIZATION .1. CHEMICAL-COMPOSITION AND OXIDATION-STATES OF TITANIUM [J].
CHIEN, JCW ;
WU, JC ;
KUO, CI .
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 1982, 20 (08) :2019-2032
[7]   MAGNESIUM-CHLORIDE-SUPPORTED HIGH-MILEAGE CATALYSTS FOR OLEFIN POLYMERIZATION .2. REACTIONS BETWEEN ALUMINUM ALKYL AND PROMOTERS [J].
CHIEN, JCW ;
WU, JC .
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 1982, 20 (09) :2445-2460
[8]   SUPERACTIVE AND STEREOSPECIFIC CATALYSTS .3. DEFINITIVE IDENTIFICATION OF ACTIVE-SITES BY ELECTRON-PARAMAGNETIC RESONANCE [J].
CHIEN, JCW ;
HU, YL .
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 1989, 27 (03) :897-913
[9]   MOLECULAR-MODELING STUDIES OF THE POLYPROPYLENE CATALYST [J].
COLBOURN, EA ;
COX, PA ;
CARRUTHERS, B ;
JONES, PJV .
JOURNAL OF MATERIALS CHEMISTRY, 1994, 4 (06) :805-812
[10]  
CORRADINI P, 1988, TRANSITION METALS OR, P337