Surface science study of model Ziegler-Natta catalysts

被引:33
作者
Magni, E
Somorjai, GA
机构
[1] UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720
[2] UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720
关键词
amorphous thin films; catalysis; chemical vapor deposition; surface chemical reaction; titanium(IV)chloride; X-ray photoelectron spectroscopy;
D O I
10.1016/S0039-6028(96)01512-9
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 preparation and surface science study of model catalysts for the Ziegler-Natta polymerization are reported. Ultra-thin films of MgCl2 and TiCl4 have been prepared by gas phase deposition on polycrystalline Au foil in UHV conditions and are characterized by XPS. Titanium chloride films can be deposited on both MgCl2 films and clean An at 300 K in a background TiCl4 pressure of 1 x 10(-8)-5 x 10(-7) Torr, in the presence of an electron beam of 1 keV irradiating the substrate. The deposited titanium chloride consists of a TiCl2 multilayer film with one monolayer of TiCl4 chemisorbed at the surface. Upon exposure of AlEt3, the TiCl4 monolayer undergoes reduction and alkylation with the formation of TiCl2Et and TiClEtn species at the film surface, No evidence for TiCl3 formation is observed. These model systems are active catalysts for the Ziegler-Natta polymerization of both ethylene and propylene.
引用
收藏
页码:824 / 827
页数:4
相关论文
共 6 条
[1]   NEUES ZUM RAUMPROBLEM DER TETRAHALOGENIDE DER 4-GRUPPE [J].
BRAND, P ;
SACKMANN, H .
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE, 1963, 321 (5-6) :262-269
[2]   Electron irradiation induced chemical vapor deposition of titanium chloride on gold and on magnesium chloride thin films. Surface characterization by AES, XPS, and TPD [J].
Magni, E ;
Somorjai, GA .
JOURNAL OF PHYSICAL CHEMISTRY, 1996, 100 (35) :14786-14793
[3]   ELECTRON-IRRADIATION-INDUCED REDUCTION OF MAGNESIUM-CHLORIDE THIN-FILMS DEPOSITED ON GOLD - XPS AND ISS STUDY [J].
MAGNI, E ;
SOMORJAI, GA .
SURFACE SCIENCE, 1995, 341 (03) :L1078-L1084
[4]   ETHYLENE AND PROPYLENE POLYMERIZATION CATALYZED BY A MODEL ZIEGLER-NATTA CATALYST PREPARED BY GAS-PHASE DEPOSITION OF MAGNESIUM-CHLORIDE AND TITANIUM CHLORIDE THIN-FILMS [J].
MAGNI, E ;
SOMORJAI, GA .
CATALYSIS LETTERS, 1995, 35 (3-4) :205-214
[5]   Preparation of a model Ziegler-Natta catalyst: Electron irradiation induced titanium chloride deposition on magnesium chloride thin films grown on gold [J].
Magni, E ;
Somorjai, GA .
SURFACE SCIENCE, 1996, 345 (1-2) :1-16
[6]   PREPARATION OF A MODEL ZIEGLER-NATTA CATALYST SURFACE SCIENCE STUDIES OF MAGNESIUM-CHLORIDE THIN-FILM DEPOSITED ON GOLD AND ITS INTERACTION WITH TITANIUM CHLORIDE [J].
MAGNI, E ;
SOMORJAI, GA .
APPLIED SURFACE SCIENCE, 1995, 89 (02) :187-195