Olefin polymerizations with zirconocene supported on SiO2 modified by MgO, NaOH and LiOH

Mesoporous magnesium oxide and its composites: Preparation, characterization, and removal of 2-chloroethyl ethyl sulfide

“…As an alternative route, it was reported that silica impregnated with magnetite nanoparticles [10] and surface modified silica [11][12][13][14] are a good candidate to improve the adsorption capacity and reactivity of sulfur and nitrogen compounds. Then, to improve the physical properties and sorption capacity, porous silica was added to MgO particle by using various methods such as spray pyrolysis (a specific surface area of about 148 m 2 /g) [5], supercritical drying under different prehydrolysis conditions for TEOS (a specific surface between 207 and 340 m 2 /g) [15], a wet mixing method (a specific surface area under 520 m 2 /g) [16], and a sol-gel method (a specific surface area between 86 and 317 m 2 /g) [17].…”

MAO- and Borate-Free Activating Supports for Group 4 Metallocene and Post-Metallocene Catalysts of α-Olefin Polymerization and Oligomerization

“…Modification of silica by MgO, LiOH, or NaOH resulted in the formation of new phases capable of activation of rac -[SiMe 2 (η 5 -4,5,6,7-tetrahydroinden-1-yl)]ZrCl 2 ( Zr28 )/ i Bu 3 Al in the polymerization of ethylene and propylene [ 176 ]. The highest catalytic activities were detected when using SiO 2 /MgO support, they comprised 70 kg PE ∙g Zr −1 ∙h −1 and 340 kg PP ∙g Zr −1 ∙h −1 .…”

“…The acid strengths of SiO 2 and MgO and Mg(OH) 2 were found to be weak [ 177 ]; therefore, in SiO 2 /MgO phase, SiO 2 and MgO have undergone a reorganization of the bonding structure with a formation of new acidic sites that are required for high activity of zirconocene in propylene polymerization. The role of the basic anionic sites had been also raised in [ 176 ], without mechanistic interpretation.…”

“…The Hammett acidity function (H0) for superacid sites of sulfated metal oxides (SMO) was up to <-16. The common methods of the preparation of SMO are the treatment of precipitated hydroxides with H2SO4 with subsequent calcination, thermal decomposition of metal sulfate hydrates, or Modification of silica by MgO, LiOH, or NaOH resulted in the formation of new phases capable of activation of rac-[SiMe 2 (η 5 -4,5,6,7-tetrahydroinden-1-yl)]ZrCl 2 (Zr28)/ i Bu 3 Al in the polymerization of ethylene and propylene [176]. The highest catalytic activities were detected when using SiO 2 /MgO support, they comprised 70 kg PE •g Zr −1 •h −1 and 340 kg PP •g Zr −1 •h −1 .…”

“…The formation of active sites on the AlPO 4 was attributed to the reaction of surface -OH groups with i Bu 3 Al [167]. Nb 2 O 5 was found to be ineffective in the activation of Zr25 ; only Nb-O-ZrMe 2 (η 5 -C 5 Me 5 ) species have been detected [82].Modification of silica by MgO, LiOH, or NaOH resulted in the formation of new phases capable of activation of rac-[SiMe 2 (η 5 -4,5,6,7-tetrahydroinden-1-yl)]ZrCl 2 (Zr28)/ i Bu 3 Al in the polymerization of ethylene and propylene[176]. The highest catalytic activities were detected when using SiO 2 /MgO support, they comprised 70 kg PE •g Zr −1 •h −1 and 340 kg PP •g Zr −1 •h −1 .…”