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Proposing Institution

Department of Chemistry University of Torino
Project Manager

Dr. Maddalena D'Amore
Via P. Giuria 5
10125 Turin
Abstract us catalysts have often a complex nature that prevents the acquisition of the atomic-level knowledge on the active sites, especially in reaction conditions. The traditional experimental methods of use in surface science hardly provide an average picture of nano-catalysts, which are still optimized empirically in the industrial practice. On the other hand, HPC resources make now possible to run efficiently parallel codes with excellent scalability in terms of both speed-up and memory requirements. Due to the recent development in Density Functional Theory and to the availability of powerful computational facilities, theory is moving towards the computational design of efficient heterogeneous catalysts. In this project we address Ziegler-Natta (ZN) catalysts for olefin polymerization as prototypes of complex nano-sized catalysts. They are computationally highly demanding systems, with a long history of experimental and theoretical collection of data. Any description of ZN catalysts should take into account: 1) the presence of multiple sites on different MgCl2 surfaces and on defective positions; 2) the fact that the adducts of catalytic interest – involving TiCl4, aluminum alkyls and very bulky aromatic donors – have very low degree of coverage; and 3) the fact that after reduction of Ti species unrestricted DFT calculations are necessary. For these reasons, an accurate ab-initio prediction of thermodynamics and kinetics of our systems will require highly expensive calculations and huge computational resources. CRYSTAL in its Massive Parallel version (MPPCRYSTAL) will be the ab-initio code of election. Thanks to thousands cores, it will be possible to simulate nano-crystals of up to thousand atoms at high UB3LYP-D/TZVP level of computation. In addition, we will perform an analysis of plausible reactivity indicators, such as electron density transfers, in order to evaluate the occurrence of specific reaction mechanisms, on the basis of ELF and MPDs theories. The project stands on a synergetic cooperation between theoreticians, spectroscopists and industrial partners (DPI Project PO2.0-2016-005). In the short period, the results are expected to contribute to the rationalization of the relation between the structure of the active sites, and their reactivity and selectivity towards olefins. On a long-term scale our results might lead to improve both productivity and stereo-specificity of these catalysts, with a potential positive outcome from an industrial perspective, as well as to improve the performances of the code when running on thousands of processors.

Impressum, Conny Wendler