Storage time effect on dynamic structure of MgCl2.nEtOH adducts in heterogeneous Ziegler-Natta catalysts
Journal Title: Polyolefins Journal - Year 2014, Vol 1, Issue 1
Abstract
Primary MgCl2.3.3EtOH adduct (PCT1) was prepared by melt quenching method and then submitted into a programmed thermal dealcoholation project using a fluidized bed reactor. During thermal dealcoholation program, different MgCl2.nEtOH support samples with n= 3.0, 2.7, 2.4, and 2.1 were selected and named as PCT2 to PCT5, respectively. Structural analysis of the support samples showed a significant increase in the surface area, from 7.4 m2/g to 12.8 m2/g, together with the decrease in peaks height at 2θ≈ 8.9 and 9.7˚ by moving from PCT1 to PCT5. After characterization of support samples, final catalysts were prepared by reacting these samples with TiCl4 and examined in slurry phase propylene polymerization. Prepared catalysts showed similar stereospecifities but different activities in the polymerization experiments, so that, with proceeding dealcoholation from PCT1 to PCT2 catalyst activity was reached a maximum amount of 2.9 kgPP/g Cat.h, and then by further dealcoholation, from PCT2 to PCT5, catalyst activity decreased gradually. In the last section, effect of time interval between thermal dealcoholation and catalyst preparation, which is called storage time, on the crystal and morphological characteristics of the two of the best adduct samples, namely MgCl2.2.4EtOH and MgCl2.3.0EtOH, was studied, as well. Storage time greatly affected the characteristics of the adducts together with resulted catalysts, and the best catalyst activity was achieved for the ones prepared immediately after adduct preparation.
Authors and Affiliations
Najmeh Hadian, Shokoofeh Hakim, Mehdi Nekoomanesh, Naeimeh bahri-Laleh
Keywords
Related Articles
- EP ID EP283047
- DOI 10.22063/POJ.2014.904
- Views 153
- Downloads 0
Copolymerization of ethylene with α-olefins over highly active supported Ziegler-Natta catalyst with vanadium active component
The new highly active supported vanadium-magnesium catalyst (VMC) has been studied in α-olefin (1-butene, 1-hexene)/ ethylene copolymerization in the presence of hydrogen. Data on the effect of α-olefin/ethylene ratio in...
Intelligent catalysts for ethylene oligomerization and polymerization
Ethylene polymerization catalysts became available in an enormous variety. The challenge in this research is to find catalysts that are able to connect ethylene molecules in such a way that not only linear chains are pro...
The effect of iodo substituents in bis(phenoxyimine) zirconium complexes on the catalytic performance of homogeneous ethylene polymerization reactions
Eight different zirconium phenoxyimine complexes were synthesized, characterized and tested as catalysts for ethylene polymerization. The phenoxyimine compounds were prepared by condensation of substituted salicylaldehyd...
Fouling mechanisms during protein microfiltration: The effects of protein structure and filtration pressure on polypropylene microporous membrane performance
A polypropylene microporous membrane (PPMM) was fabricated by thermally induced phase separation (TIPS) method. The effects of protein size and structure as well as filtration pressure on the membrane performance and fou...
Influence of annealing on anisotropic crystalline structure of HDPE cast films
High density polyethylene (HDPE) films were produced using cast film extrusion process with different draw ratios, ranging from 16.9 to 148.8. Morphology, crystallinty and orientation state of crystalline and amorphous p...