Giampiero Morini

• Research Director at LyondellBasell Industries

The nature of Ti(III) species, introduced in working models of industrial Ziegler Natta catalyst precursors, consisting of MgCl2/TiCl4 binary systems, eventually containing different Lewis basis, are studied by a combination of X- and Q-band CW and pulse EPR spectroscopy. In Ziegler Natta catalysts, Ti(III) play the double role of active catalytic...

Adducts of TiCl4 with Lewis bases used as internal or external donors in heterogeneous Ziegler-Natta (ZN) catalysis represents a fundamental interaction contributing to the final composition of MgCl2 supported ZN-catalysts. This study presents the accurate experimental evaluation, from titration calorimetry, of the formation enthalpy of TiCl4 adduc...

A study of the nucleating effects of isotactic poly(trimethylallylsilane) (iPTMAS) and poly(vinylcyclohexane) (iPVCH) for isotactic polypropylene (iPP) and their influence on the mechanical behavior of iPP is reported. The particles of catalyst are covered by poly(trimethylallylsilane) or poly(vinylcyclohexane) by polymerization of the correspondin...

Innovation of the Ziegler-Natta polymerization process for polymerization of propene that allows tailoring of the mechanical properties of isotactic polypropylene (iPP) directly in the polymerization stage is presented. The catalyst is modified by prepolymerization of trimethylallylsilane or vinylcyclohexane so that the catalyst particles are coate...

We propose a model for MgCl2-supported Ziegler-Natta catalysts, which is capable to reconcile the discrepancies emerging in the last 20 years, in which attempts have been made to rationalize experimental data by molecular models. We show that step defects on the thermodynamically more stable (104) facet of MgCl2 can lead to sites for strong TiCl4 a...

Catalyst component for the polymerization of olefins comprising Mg, Ti and an electron donor compound of the following formula (I) In which R1 to R4 groups, equal to or different from each other, are hydrogen, C1-C15 hydrocarbon groups, optionally containing an heteroatom selected from halogen, P, S, N and Si, R6 group is selected from C1-C15 hyd...

In this work we present a systematic DFT analysis of the effect of surface coverage on the coordination properties of two industrial Lewis bases, dimethyl phthalate and 9,9-bis(methoxymethyl)fluorene, to the (104) and (110) surfaces of MgCl2. Further, we investigated several possible migration pathways for the migration of the Lewis bases on the sa...

In this work, we present a systematic DFT analysis of the effect of surface coverage on the coordination properties of alkoxysilanes to the (104) and (110) surfaces of MgCl2. Furthermore, we investigated several possible migration pathways for alkoxysilane migration on the same surfaces. Our study clearly shows that complete coverage of the Mg vaca...

We present a theoretical study on possible models of catalytic active species corresponding to Ti–chloride species adsorbed at the corners of MgCl2 crystallites. First we focused our efforts on the interaction between prototypes of three industrially relevant Lewis bases used as internal donors (1,3-diethers, alkoxysilanes and succinates) and MgCl2...

In this work, we report on the structure and formation energy of uncovered MgCl2 crystallites of different shapes (hexagonal and square), sizes (up to crystallites composed of 157 MgCl2 units), and edges (crystallites presenting the (104) and (110) edges). Both uncovered crystallites and crystallites covered by dimethyl ether were considered. Our r...

The effect of oxygen plasma treatment on adhesion and surface properties of polypropylene (PP) was assessed. An oxygen rich modified PP layer, immiscible with bulk PP, was formed by the treatment. Contact angle measurements showed that macromolecular motions led with time to rearrangements of the surface layer drastically decreasing its wettability...

Infrared vibrational spectroscopy has been used to reveal the conformations of the Ziegler−Natta catalysts internal electron donor 9,9-bis(methoxymethyl)-fluorene and its selectively deuterated derivative (9,9-bis(1,1-dideutero-methoxymethyl)-fluorene), in the solid state, complexed with TiCl4 and MgCl2 and in the catalyst precursor. The experiment...

A calorimetric investigation on the reactions of TiCl4 with phthalates in 1,1,2,2-tetrachloroethane (TCE) is presented in order to better understand the complex interactions present in Ziegler-Natta catalytic systems. The Lewis bases diethyl isophthalate (L1), diethyl terephthalate (L2) and the ortho-isomer diethylphthalate (L3), have been chosen t...

Calorimetric and computational investigation on the interaction of TiCl4 with some Lewis bases (esters and ethers) is presented. The bases were chosen for their relevance in heterogeneous Ziegler-Natta polymerization of propene. Comparison of the theoretical data with the calorimetric data indicates that calculations consistently underestimate the...

We present a theoretical study of the basic interactions occurring at supported hetereogenous Ziegler−Natta catalytic systems. We first investigated the interaction between prototypes of each class of industrially relevant internal donors (1,3-diethers, alkoxysilanes, phthalates, succinates) and the MgCl2 support. Our analysis indicates that donors...

Extensive calorimetric investigations on the interaction of TiCl4 with some Lewis bases are presented. Some of the bases were chosen for their industrial relevance in heterogeneous Ziegler−Natta polymerization of propene (ethyl benzoate, L2, diisobutyl phthalate, L3, (2R,3S)-diethyl 2,3-diisopropylsuccinate, L6, (2S,3S)-diethyl 2,3-diisopropylsucci...

The FT-Raman spectra of a series of mechanically prepared MgCl2–TiCl4 samples with increasing content of TiCl4 have been recorded. Raman scattering lines in the range 600–100cm−1 reveal the formation of TiCl4 molecules complexed on the lateral cuts of activated MgCl2 crystals. This pattern of lines suggests that atleast three types of complexes are...

This article describes the quantitative aspects of the isoselectivity distribution of isospecific centers in five supported titanium‐based Ziegler–Natta catalyst systems containing different internal and external organic donors. Highly crystalline poly(propylene) fractions of the polymers (insoluble in o ‐xylene at 95 °C) were analyzed by analytica...

The vibrational Infrared and Raman Spectra of a MgCl2-TiCl4 Ziegler-Natta catalyst precursor with a 50/1 MgCl2/TiCl4 ratio have been recorded. The Raman spectrum of this catalyst precursor, in the range 50-500 cm−1, shows clear scattering lines which can be assigned to the complex MgCl2-TiCl4, well separated from those of the initial species. Analo...

Ziegler‐Natta catalysts, discovered in the years 1953–1954, account today for a production volume of ∼65 million tons of polyolefins, including mainly polyethylene and polypropylene products. Since their first discovery, the development of Ziegler‐Natta catalysts has been relentless, and their evolution is the result of the exploitation, starting f...

Continuous fine tuning of both chemistry and architecture of heterogeneous, isospecific MgCl2/TiCl4 catalyst systems for propene polymerization has led to a significant improvement in their performances in terms of activity, stereoselectivity, and capability to control both molecular parameters and morphology of the resulting polymers. As a result,...

Poly(propylene)s prepared using MgCl2-supported catalysts containing different electron donors have been characterized using temperature rising elution fractionation (TREF), gel permeation chromatography (GPC) and 13C NMR analysis. In addition, the regio- and stereochemical composition of oligomeric fractions present in selected polymers has been d...

Poly(propylene)s prepared using MgCl2-supported catalysts containing different electron donors have been characterized using temperature rising elution fractionation (TREF), gel permeation chromatography (GPC) and 13C NMR analysis. In addition, the regio- and stereochemical composition of oligomeric fractions present in selected polymers has been d...

An analysis was carried out of some Ziegler–Natta catalysts precursors by small- and wide-angle X-ray scattering in order to get information on the crystallites dimensions, structural disorder and surface areas. The results were correlated with catalytic activities in polymerization of propylene. It was shown that the structural variations, which m...

Energy calculations relative to the adsorption of several substituted 1,3-diethers on the unsatured (100) and (110) lateral cuts of MgCl2 are presented. Independent of the particular approach used, coordination of the diethers on the (110) cut is always preferred. The energy difference favoring the diether coordination on the (110) cut depends on t...

Studies on the effects of hydrogen, monomer concentration and temperature in propene polymerization using high-activity MgCl2-supported catalysts have revealed that the effects of the catalyst on polymer yield, isotacticity and molecular weight are interrelated and dependent on both regio-and stereoselectivity. The high hydrogen sensitivity of cata...

A study of the effect of polymerization temperature on the microtacticity of poly(propylene) prepared using various MgCl2-supported catalysts has shown that, in almost all cases, an increase in temperature leads not only to higher proportions of isotactic polymer but also to increased stereoregularity of the isotactic fraction. The results indicate...

The behavior in propylene polymerization of divalent titanium compounds of type [η6-areneTiAl2Cl8], both as such and supported on activated MgCl2, has been studied and compared to that of the simple catalyst MgCl2/TiCl4. Triethylaluminium was used as cocatalyst. The Ti–arene complexes were active both in the presence and in the absence of hydrogen,...

Several polypropene samples, synthesized with different catalytic systems based on TiCl4 supported on activated MgCl2 and different electron donors, were studied using both preparative and analytical temperature-rising elution fractionation (TREF). The experimental results show that each variation in the catalytic system is clearly reflected in the...

13C NMR analysis of poly(propylene) fractions of different tacticity, obtained using a catalyst system of type MgCl2/TiCl4/diisobutyl phthalate – AlEt3 – diether, has provided further evidence that the active species in this system are similar to those in which the ether is used as “internal” rather than “external” donor. Chain-end analysis of rela...

Three diethers, 2,2-diisobutyl-1,3-dimethoxypropane, 2,2-dicyclopentyl-1,3-dimethoxypropane, and 2-ethyl-2-butyl-1,3-dimethoxypropane, differing in the bulkiness of the alkyl substituents in position 2, have been used as internal donors in MgCl2−TiCl4−diether/AlR3 catalysts for the polymerization of propylene. The performance of the three diether-b...

13C NMR analysis of the chain-end distribution of poly(propylenes) prepared using the highly active catalyst system MgCl2/TiCl4/diether—AlEt3 has revealed particularly high proportions of butyl chain-ends in polymers prepared at relatively low hydrogen pressures. This indicates that the high sensitivity of this type of catalyst to hydrogen, both wi...

A study on a new generation of MgCl2-supported Ziegler-Natta catalyst, which contain dialkylpropane diether as internal donors and have the property of producing highly active and stereospecific catalyst without any external donor, has been performed. The behavior of three different diethers (2,2-diisobutyl-1,3-dimethoxypropane, 2,2-dicyclopentyl-1...

The results of 13C NMR analysis of chain end groups of poly(propylene) samples prepared with traditional δ-TiCl3 and high yield TiCl4/MgCl2 catalysts in the presence of different 13C enriched alkylaluminium cocatalysts — Al(13CH2CH3)3, Al(13CH2CH3) (is-o-C4H9)2 and Al(13CH2CH3)(CH3)2 — have been compared. The data show that, while molecular weights...

The copolymerization of propylene with small amount of ethylene using MgCl2-supported stereospecific catalysts in combination with different Al-alkyls was performed. At least for the particular catalyst used, it resulted that TEA and TIBA are the preferred Al-alkyls; whereas, the mixture TEA/DEAC provides copolymers with a high amount of xylene sol...

The role of Lewis bases in MgCl2 supported catalysts for olefin polymerization is a subject of continuous interest and discussion in order to obtain more and more active and stereospecific catalysts and to explain their stereoregulating mechanism. Through molecular calculation and conformational analysis it was possible to identify chelating diethe...

The role of Lewis bases in MgCl2 supported catalysts for polypropylene has been reviewed. Experimental data strongly support the hypothesis that the Lewis base competes with TiCl4 for selective coordination on unsaturated Mg ions located on different faces of MgCl2. The choice of chelating Lewis bases particularly able to complex tetracoordinate Mg...

The key factor that allowed the outstanding development of polyolefins has been the Ziegler-Natta catalysis that played and is still playing an innovative role in this field. More and more sophisticated new catalysts have made possible advanced polymerization technologies, improved product grades and a broader range of applications, through a bette...

The reactions between the components of high activity catalysts for polypropylene, aluminum alkyls, magnesium chloride, titanium halides and Lewis bases, are discussed with particular reference made on their influence on the activity and stereospecificity of the catalytic system.

XPS, SEM, SSIMS, FTIR-ATR, water-in-air, and air-in-water contact angle measurements have been used to unambiguously characterize the locus of failure of PP/epoxy joints. In the case of untreated PP, the fracture has been found adhesive, whereas in oxygen plasmatreated PP, it is cohesive, within bulk PP, but close to the modified PP-bulk PP interfa...

Oxygen plasma treatment of polypropylene (PP) surfaces led to introduction of oxygencontaining functionalities, with consequent improvement of surface wettability. A combination of X-ray photoelectron spectroscopy (XPS), static secondary ion mass spectroscopy (SSIMS), and contact angle measurements (water-in-air and air-in-water) allowed us to char...

The adhesive properties of PET have been enhanced by treatments with alkaline solutions and CF4/02 plasmas. Alkaline solution induce hydrolysis of the polyester and etching, with consequent strong roughening of the surface. Adhesion siemed more related to etching than to surface chemistry modifications, suggesting a prominent role of mechanical int...

The substitutions of protonated pyridine, quinaldine, lepidine, and 3-cyano- and 4-cyanopyridine by Ph, Me, n-Pr, n-Bu, i-Pr, t-Bu, α-tetrahydrofuranyl (α-THF), dioxanyl, and benzyl radicals are affected by the nature of the solvent as concerns the regioselectivity and the relative rates. The isotope effect is negligible with the phenyl radical, bu...

The rate constants for the addition of the phenyl radical to protonated and unprotonated 4-substituted pyridines have been determined by competition with chlorine abstraction from CCl4. The constants range from 2 × 105 to 6 × 106 M-1 s-1 depending on the substituent and on the degree of protonation. The phenyl radical shows a clear-cut nucleophilic...

The homolytic benzylation of protonated 4-cyanopyridine, quinoline, 2-methyl- and 4-methylquinoline, isoquinoline, and quinoxaline is investigated. The great influence of the polar effect and of the reversibility of the addition of the benzyl radical on the reaction selectivity is discussed. It is put forward the hypothesis that the HSAB principle...