TEMPERATURE-PROGRAMMED DECOMPOSITION OF SILICA-SUPPORTED MGCL2 THF/TICL4 CATALYST AND EFFECT OF THERMAL-TREATMENT ON ETHYLENE POLYMERIZATION RATE/

Silica supported MgCl2/THF/TiCl4 catalyst (SiO2/MgCl2/THF/TiCl4) was p repared, and then decomposed thermally. The amount of produced gas [te trahydrofuran (THF) and 1,4-dichlorobutane (DCB)] was measured with ga s chromatography (GC) and mass spectrometer. SiO2/MgCl2/THF/TiCl4 cata lyst started to decompose around 85 degrees C, and further decomposed at 113, 150 and 213 degrees C. THF was mainly produced, but very small amount of DCB evolved during temperature programmed decomposition (TP D), while unsupported MgCl2/THF/TiCl4 produced DCB significantly. Poly merization rate of ethylene with SiO2/MgCl2/THF/TiCl4 decreased when i t was preheated at 85 and 110 degrees C for 5 and 60 min, respectively , while that of unsupported MgCl2/THF/TiCl4 increased after same pretr eatment condition. It can be suggested that Mg/Ti bimetallic complex a nchored on the surface of silica through OH group of it has weak inter action between Mg and Ti species.