Chlorination of Mg(OEt)2 with Halocarbons: A Promising Approach for Eliminating Chlorine-Containing Activators from Ziegler–Nattas’ Recipes

• Published in: Industrial & engineering chemistry research Vol. 61; no. 32; pp. 11708 - 11717
• Main Authors: Jandaghian, Mohammad Hossein, Maddah, Yasaman, Sepahi, Abdolhannan, Hosseini, Shahin, Nikzinat, Ehsan, Masoori, Maryam, Afzali, Kamal, Rashedi, Reza, Houshmandmoayed, Saeed
• Format: Journal Article
• Language: English
• Published: American Chemical Society 17.08.2022
• Subjects: Kinetics, Catalysis, and Reaction Engineering
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.2c01857

Due to the many risks of using chlorinated alkylaluminum cocatalysts (CACs), reducing or omitting their amount in methods used for synthesizing Ziegler–Natta catalysts (ZNCs) has always been a dream of polymer chemists. CACs play a crucial role in the chlorination of Mg­(OR)2 supports, which are the most industrially favorable precursors in ZNCs’ recipes. In this article, using a systematic investigation, an initiative approach has been suggested to chlorinate the supports using halocarbons and chlorine-free alkylaluminum cocatalysts (CFACs). It was evidenced that the successive addition of a CFAC and a halocarbon to a suspension of Mg­(OR)2 is a reliable method for chlorine atom exchange between the halocarbon and Mg­(OR)2. Doing so, a highly active ZNC was produced and characterized mainly by inductively coupled plasma, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. In the next step, the catalyst’s performance in monomodal and bimodal copolymerization reactions of ethylene and 1-butene was investigated, and the produced copolymers were fully characterized. The characterizations were carried out using numerous techniques such as rheometric mechanical spectroscopy (RMS), self-nucleation and annealing, differential scanning calorimetry, mechanical tests, and so forth, and their results were compared with a famous ZNC whose support was chlorinated with a CAC. Finally, a possible mechanistic pathway for the reaction between Mg­(OR)2 and halocarbons using CFACs as a chlorine transporter was described. All in all, it was revealed that the new approach could be relied upon as a promising way to chlorinate Mg­(OR)2 supports without using dangerous and corrosive CACs. The produced copolymers using the new formulation had the same physical and mechanical properties as those made by industrial counterparts.