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ECMO, or \"artificial lung,\" which has played a crucial role in the fight against COVID-19, uses PMP hollow fiber membranes as its main component, the membrane lung. Products in the PMP membrane value chain, such as the acrylide dimer 4-methyl-1-pentene (4MP1) and PMP resin, are still exclusively controlled by foreign suppliers; China has not yet been able to achieve industrialization of these products, which illustrates the difficulty involved. Concerns regarding the product chain have come to light. The preparation of PMP membranes begins with the polymerization of acrylonitrile to produce 4MP1 monomer. In the 1960s, after British Petroleum built the first 4MP1 production plant with a capacity of 2,000 tons per year, Japan, the United States, and other countries subsequently constructed plants with capacities ranging from 20,000 to 100,000 tons per year. Secondly, the propylene dimer 4MP1 is polymerized to form PMP resin under the action of Ziegler-Natta catalysts. PMP resin was first developed by the British company ICI in 1965, and mass production began in 1968. Subsequently, Mitsubishi Chemical Corporation of Japan obtained the authorization to begin production and bring it to market in 1973. Currently, the company remains the world’s only manufacturer of PMP resin. Finally, PMP resin will be further used to manufacture PMP hollow fiber membranes; currently, only Membrana, a company under 3M, is capable of producing them. In summary, China is currently unable to produce independently the entire product chain consisting of propylene dimer 4MP1, PMP resin, and PMP hollow fiber membranes, which in turn limits the localization of ECMO systems in the country. The outbreak of COVID-19 has further exposed this issue, bringing to the surface the underlying concerns of this industrial chain. The catalyst system is key. While taking into account energy consumption and economic factors, whether the propylene dimerization process can produce 4MP1 to the greatest extent possible depends primarily on the catalyst system used. The catalysts for the selective dimerization of propylene to produce 4MP1 are primarily based on alkali metals; they must contain at least one alkali metal in its elemental form, either as a carbonate or bicarbonate, along with a co-catalyst. The active components of these catalysts are sodium and potassium metals. The first catalyst used for the industrial production of 4MP1 was developed by BP and is prepared by dispersing metallic sodium in anhydrous potassium carbonate. Using the aforementioned catalyst system for propylene dimerization is also the only method currently used industrially to produce 4MP1. Data show that adding different co-catalysts to alkali metal catalysts, or including certain other components in the carrier, can improve the strength, activity, and lifespan of the catalysts. For example, using metal carbonates as carriers, supplemented by graphite and the addition of pore-expanding agents, along with composite metals as active components, can all improve these parameters. Using the new solid superbase potassium/kalium carbonate catalyst for the dipolymerization of propylene to 4MP1, the propylene conversion rate was 43%, the selectivity for the dimer product was 95%, and the selectivity for 4MP1 was 86%. Since the active components in this reaction are all alkali metals, there is very little room for variation, making the choice of carrier crucial. The isomerization reaction must be suppressed. The currently accepted mechanism for the catalytic dimerization of propylene to 4MP1 using an alkali metal system is that propylene diffuses into the super-strong basic sites on the catalyst, where its protons are removed and it combines with the alkali metals on the catalyst surface to form a reactive intermediate – the allyl anion. Under the reaction conditions, the allyl anion readily forms the unstable 4MP1 anion; this 4MP1 anion undergoes a hydrogen exchange reaction with propylene molecules to produce the more stable allyl anion and the target product, thus forming a single-cycle catalytic process. Among them, a very small portion of the allyl anions reacts with propylene molecules to form the isomer 1-hexene. The allyl anion exhibits better stability compared to the 4MP1 anion, allowing the concentration of the 4MP1 anion to be kept low throughout the reaction process. This prevents it from further polymerizing with propylene molecules to form trimers or polymers, thereby ensuring high selectivity for the dimer. In this reaction, two main types of side reactions are involved: one is the oligomerization side reaction, and the other is the isomerization side reaction. 4MP1 is the thermodynamically least stable hexaene, and it readily isomerizes to form more stable hexaenes. Therefore, during the actual production of 4MP1, the isomerization reaction can be suppressed by reducing the content of 4MP1 in the reaction phase. In industrial plants that are already in operation in countries such as the UK, the single-pass conversion rate of propylene is controlled at 7%–11%, clearly to suppress the isomerization reaction. Another approach is to increase the rate of desorption of the product from the active sites of the catalyst. Potassium carbonate has a low specific surface area and a simple pore structure; the alkali metal loaded on potassium carbonate serves as an excellent catalyst for the dimerization of propylene to 4MP1, with low isomerization activity. The optimization of catalysts using potassium carbonate as a carrier involves improving its pore structure, such as increasing the pore size, so that it can enhance conversion efficiency without affecting isomerization activity.