Theoretical investigations on Ziegler-Natta catalysis: Alkylation of the TiCl4 catalyst

Puhakka, Eini; Pakkanen, Tuula T.; Pakkanen, Tapani A.

doi:10.1016/s1381-1169(96)00433-5

Cited by 33 publications

(27 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The catalytic reactions take place on the surfaces of the MgCl 2 support. , The bulk MgCl 2 is a crystalline layered material, which exists in three polymorphs: rhombohedral α-MgCl 2 , hexagonally closed-packed β-MgCl 2 , and rotationally distorted δ-MgCl 2 . The layers are held together by dispersion and are composed of octahedral six-coordinated Mg atoms bound to three-coordinate Cl atoms (Figure A). − Lateral cut of the MgCl 2 sheets exposes catalytically relevant (104) and (110) surfaces with five- and four-coordinate Mg atoms, respectively (Figure B), which adsorb and coadsorb TiCl 4 , aluminum alkyls, and Lewis bases. − The (110) surface is less stable than the (104) surface because of the lower coordination numbers of surface Mg atoms, ,, but adsorption of other catalyst components may reverse the stability order in favor of (110). , Reactions taking place on the surface eventually lead to the formation of active sites for olefin polymerization. ,,− …”

Section: Introductionmentioning

confidence: 99%

Adsorption of Titanium Tetrachloride on Magnesium Dichloride Clusters

Zorve

Linnolahti

2018

ACS Omega

View full text Add to dashboard Cite

Magnesium dichloride and titanium tetrachloride are key components in heterogeneous Ziegler–Natta olefin polymerization catalysis. We have determined the preferred binding modes of titanium tetrachloride on magnesium dichloride clusters at the M06-2X level of theory, thus accounting for dispersion. A systematic study was carried out to locate the lowest energy isomers of (MgCl 2 ) n (TiCl 4 ) m complexes. Altogether ca. 1000 complexes with n ranging from 1 to 19 and m from 1 to 13 were studied. In line with the previous literature, the results consistently show that adsorption of TiCl 4 onto MgCl 2 preferably leads to octahedral six-coordination for both Mg and Ti atoms. This can be achieved by mononuclear binding of TiCl 4 and binuclear binding of Ti 2 Cl 8 on (110) and (104) surfaces of MgCl 2 , respectively. The preferred octahedral six-coordination is also achieved by binding of TiCl 4 on defect sites, of which the most striking example is trinuclear binding mode at corners of the clusters. Overall, the results highlight the relevance of multinuclear binding of TiCl 4 on MgCl 2 .

show abstract

Section: Introductionmentioning

confidence: 99%

Adsorption of Titanium Tetrachloride on Magnesium Dichloride Clusters

Zorve

Linnolahti

2018

ACS Omega

View full text Add to dashboard Cite

show abstract

“…Additionally, accurate experimental data would provide the unique opportunity to validate the computational chemistry protocols, which are largely used to characterize ZN catalytic systems. 18,19,20,21,22,23 Unfortunately, the reliability of these calculations has always been an open question, not least due to the scarcity of accurate experimental data to be used as reference in benchmark studies. Indeed, one of the most typical approaches consisted in benchmarking density functional theory (DFT) methods versus as accurate wave function based methods, typically at the coupled cluster level with iterative treatment of single and double excitations, and perturbative inclusion of triple excitations, which is abbreviated as CCSD(T) method.…”

Section: Introductionmentioning

confidence: 99%

Accurate experimental and theoretical enthalpies of association of TiCl₄ with typical Lewis bases used in heterogeneous Ziegler–Natta catalysis

Credendino

Minenkov

Liguori

et al. 2017

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Adducts of TiCl with Lewis bases used as internal or external donors in heterogeneous Ziegler-Natta (ZN) catalysis represent a fundamental interaction contributing to the final composition of MgCl supported ZN-catalysts. This study presents the accurate experimental evaluation, from titration calorimetry, of the formation enthalpy of TiCl adducts with 15 Lewis bases of industrial interest. In addition, we report the accurate energies of association of TiCl with the same Lewis bases from calculations at the DLPNO-CCSD(T) level of theory. These accurate experimental and theoretical association values are compared with selected methods based on density functional theory (DFT) in combination with popular continuum solvation models. Calculations suggest that the PBE-D3, and M06 functionals in combination with a triple-ζ plus polarization quality basis set provide the best performance when the basis set superposition error (BSSE) is not removed from the association energies. Cleaning the association energies with the BSSE with the counterpoise protocol suggests B3LYP-D3, TPSS-D3 and M06L as the best performing functionals. The introduction of solvent effects with the PCM and SMD continuum solvation models allows the DFT-based association enthalpies to be compared with the experimental values obtained from titration calorimetry. Both solvation models in combination with the PBE-D3, PBE0-D3, B3LYP-D3, TPSS-D3, M06L, and M06 functionals provide association enthalpies close to the experimental values with MUEs in the range of 10-15 kJ mol.

show abstract

“…Ziegler‐Natta (ZN) catalysis is one of the most important catalytic processes, which produces around 150 million tons of polyolefins/year, and has a billion dollar market [1] . Since its discovery in the 1950s by Karl Ziegler and Giulio Natta, for which they received the Nobel prize in 1963, [2,3] continuous efforts to improve the performance of the ZN systems, concerning their activity and the selectivity, have been undertaken, along with understanding at the molecular level, by employing various experimental [4–11] and computational tools [12–34] . The main components of the ZN system are (i) MgCl 2 as a catalyst support, (ii) TiCl 4 as precatalyst, (iii) triethylaluminum ( teal ) as an alkylating agent, and (iv) Lewis base donors (e. g. oxygen‐containing molecules and nitrogen‐containing polymers [35] ).…”

Section: Introductionmentioning

confidence: 99%

Insights into the Nature of Self‐Extinguishing External Donors for Ziegler‐Natta Catalysis: A Combined Experimental and DFT Study

et al. 2020

View full text Add to dashboard Cite

Developing donors for Ziegler‐Natta (ZN) catalysis to control the polymerization reaction and produce polymers with desirable properties has always been challenging due to the multi‐component nature of the catalytic systems. Here, we have developed a new synthetic protocol for making two external donors, D1 (2,2,2‐trifluoroethyl myristate) and D2 (2,2,2‐trifluoroethyl palmitate) that show self‐extinguishing properties, followed by a systematic DFT study to understand this peculiar property of these donors. D1 and D2 can undergo parallel reactions with aluminum and titanium species present in the system to produce ketones and aldehydes, which are poisons for ZN catalytic systems, thus explaining their self‐extinguishing nature. The non‐covalent interaction between the long alkyl chain of the donors with the surface plays a vital role in determining the donors′ self‐extinguishing nature. There is a significant thermodynamic preference for the binding of the donor with the longer alkyl chain at the titanium center. The current work, therefore, provides interesting insights into how self‐extinguishing donors function in ZN catalytic systems.

show abstract

Theoretical investigations on Ziegler-Natta catalysis: Alkylation of the TiCl4 catalyst

Cited by 33 publications

References 40 publications

Adsorption of Titanium Tetrachloride on Magnesium Dichloride Clusters

Adsorption of Titanium Tetrachloride on Magnesium Dichloride Clusters

Accurate experimental and theoretical enthalpies of association of TiCl₄ with typical Lewis bases used in heterogeneous Ziegler–Natta catalysis

Insights into the Nature of Self‐Extinguishing External Donors for Ziegler‐Natta Catalysis: A Combined Experimental and DFT Study

Contact Info

Product

Resources

About

Theoretical investigations on Ziegler-Natta catalysis: Alkylation of the TiCl4 catalyst

Cited by 33 publications

References 40 publications

Adsorption of Titanium Tetrachloride on Magnesium Dichloride Clusters

Adsorption of Titanium Tetrachloride on Magnesium Dichloride Clusters

Accurate experimental and theoretical enthalpies of association of TiCl4 with typical Lewis bases used in heterogeneous Ziegler–Natta catalysis

Insights into the Nature of Self‐Extinguishing External Donors for Ziegler‐Natta Catalysis: A Combined Experimental and DFT Study

Contact Info

Product

Resources

About

Accurate experimental and theoretical enthalpies of association of TiCl₄ with typical Lewis bases used in heterogeneous Ziegler–Natta catalysis