Dalian University of Technology Achieves Major Technological Breakthrough in Polyolefin Key Monomer Synthesis

Recently, a research team led by Professor Liang Changhai from the School of Chemical Engineering at the university, in collaboration with Sinopec Zhenhai Refining & Chemical Company, successfully produced qualified 4-methyl-1-pentene (4M1P) for the first time on a hundred-ton scale propylene dimerization pilot plant. This marks a significant and phased technological breakthrough for China in the synthesis of this high-end specialty monomer.

Currently, 4M1P is mainly produced through propylene dimerization, which is a strongly exothermic process with complex product distribution and high spontaneity. To achieve efficient and directed conversion of propylene to the target product 4M1P, precise control of catalysts and process conditions is crucial.

In early 2018, a research team led by Professor Liang Changhai collaborated with Sinopec Zhenhai Refining & Chemical to conduct systematic research and development. Starting from laboratory-scale batch reactor tests and gradually scaling up to continuous reactor processes, they eventually constructed a hundred-ton pilot plant, establishing a complete pathway from fundamental research to engineering transformation.

The research team overcame a series of challenges, including the preparation difficulties of scaling catalysts from gram to kilogram, safe material transfer, and the matching of process equipment. After several years of continuous research and development, through extensive experiments and optimization, they successfully developed a high-efficiency catalyst. This enabled the selective synthesis of 4M1P from 17 possible reaction pathways, ultimately achieving a product purity of up to 99.3%. The key indicators surpass those of imported similar products, realizing high-quality domestic substitution.

It is reported that 4M1P is an important branched α-olefin. On the one hand, it can self-polymerize into poly-4-methyl-1-pentene (PMP), and on the other hand, it can be used as a comonomer for high-quality linear low-density polyethylene (LLDPE), significantly improving its toughness and optical properties. Among them, PMP is currently the lowest density thermoplastic resin known, possessing comprehensive properties such as high melting point, excellent heat resistance, high transparency, good dielectric properties, and chemical corrosion resistance. It has broad application prospects in fields such as electronics, optical instruments, high-end medical devices, and special packaging. However, the global 4M1P production capacity is highly concentrated in a few foreign enterprises, forming a monopoly.

The successful independent synthesis of 4M1P has not only laid a crucial foundation for China to break its reliance on imports for core materials in high-end medical equipment (such as ECMO "artificial lungs"), but also provided a reliable domestic high-performance material option for strategic emerging industries like 5G communication and flexible electronics.