Minoru Terano’s research while affiliated with Japan Advanced Institute of Science and Technology and other places

The data scientific approach has become an indispensable tool for capturing structure–performance relationships in complex systems, where the quantity and quality of data play a crucial role. In heterogeneous olefin polymerization research, the exhaustive and multi-step nature of Ziegler-Natta catalyst synthesis has long posed a bottleneck in synthetic throughput and data generation. In this contribution, a custom-designed 12-parallel reactor system and a catalyst synthesis protocol were developed to achieve the parallel synthesis of a magnesium ethoxide-based Ziegler-Natta catalyst. The established system, featuring a miniature reaction vessel with magnetically suspended stirring, allows for over a tenfold reduction in synthetic scale while ensuring the consistency and reliability of the synthesis. We demonstrate that the established protocol is highly efficient for the generation of a catalyst library with diverse compositions and physical features, holding promise as a foundation for the data-driven establishment of the structure–performance relationship in heterogeneous olefin polymerization catalysis.

Design of nanocomposites at a nanometer scale by controlling the orientation of fillers can lead to substantial improvement in properties. In this study, biaxially oriented PP (BOPP) was exploited for templating control the growth and orientation of nanoparticles. Silicon alkoxide was impregnated in the amorphous space of BOPP using supercritical CO2-assisted impregnation. The subsequent sol-gel reaction led to the in-situ formation of highly dispersed silica nanoparticles. Restriction of the particle growth by the confined amorphous space in BOPP induced the formation of anisotropic particles. We showed that the synergistic contribution of the formation of anisotropic particles with preferential orientation and the crystalline orientation of the matrix brought dramatic enhancement in the reinforcement.

The combination of genetic algorithm-based global search and local geometry optimization enables nonempirical structure determination for complex materials such as practical solid catalysts. However, premature convergence in the genetic algorithm hinders the determination of the global minimum for complicated molecular systems. Here, we implemented a distributed genetic algorithm based on the migration from a structure database for avoiding the premature convergence, and thus we realized the structure determination for TiCl4-capped MgCl2 nanoplates with experimentally consistent sizes. The obtained molecular models are featured with a realistic size and nonideal surfaces, representing actual primary particles of catalysts.

Talk: Revisiting the Identity of δ-MgCl2: Structure and Properties of Nano-Clusters by DFT, Spectroscopy and Machine Learning.How Modelling Uncovers the Origin of Industrial Catalysis

δ-MgCl2 support is an essential component of highly active Ziegler-Natta catalysts. The microstructure of δ-MgCl2 in modern industrial catalysts is extremely disordered, so is hard to determine using only powder X-ray diffraction (PXRD). Several structural models have been proposed, such as nano-sized platelet crystallites and one-dimensional chain-like structures. We used atomic pair distribution function (PDF) based on total X-ray scattering and simulations with nanoparticle models in addition to PXRD to investigate the detailed structure of δ-MgCl2. We found that δ-MgCl2 in modern catalysts consists of nano-sized platelet crystallites with stacking disorder, regardless of the preparation protocol. Here, we review our recent findings of the structure determination of δ-MgCl2. Fullsize Image

Understanding the structure and properties of MgCl2/TiCl4/ID nanoclusters is a key to uncover the origin of Ziegler-Natta catalysis. In this work MgCl2/TiCl4 nanoplatelets derived by machine learning and DFT calculations have been used to model the interaction with ethyl-benzoate EB (as internal donor) with available exposed sites of binary TixCly/MgCl2 systems. The influence of vicinal Ti2Cl8 and coadsorbed TiCl4 on energetic, structural and spectroscopic behaviour of EB has been considered. The adsorption of homogeneous-like TiCl4EB and TiCl4(EB)2 at the various surface sites have been also simulated. Calculations have been carried out by employing B3LYP-D2 and M06 functionals. The adducts have been characterized by computing IR and Raman spectra that have been found to provide specific fingerprints useful to identify surface species; IR spectra have been successfully compared to available experimental data.

A synthetic scheme for particle engineering of magnesium ethoxide (Mg(OEt)2) as a solid precursor for olefin polymerization catalysts was presented based on the exploitation of various organic compounds as a modulator in a post-addition step. It was found that the introduction of a modulator after the particle formation helped to modulate the macroscopic features and the crystalline structure of Mg(OEt)2 to the great extent without destructing the macroparticle morphology. Different types of organic compounds were exploited and their influences on the Mg(OEt)2 structural features were investigated. It was found that organic compounds with higher polarity caused strong modulation of Mg(OEt)2, which allowed particle and pore engineering of the final catalyst, and in turn its performance in propylene polymerization.