In Situ Catalyst Formation for Narrow Polydiene Distribution

The patent combines the metal-containing compound, carbene, and alkylating agent into a single catalyst composition that can be prepared in one step. The metal-containing compound and carbene react in situ to form the active catalyst species, eliminating the need for separate pre-preparation of the carbene complex. This merging of components resolves the contradiction by achieving narrow molecular weight distribution through the unified catalyst system while simplifying the manufacturing process.

The catalyst composition is designed so that the metal-containing compound and carbene are pre-combined in the catalyst formulation before polymerization. This preliminary combination ensures that the active catalyst species forms in situ under controlled conditions, producing polymers with narrow molecular weight distribution without requiring complex post-preparation steps or separate carbene complex preparation.

The catalyst system is segmented into distinct components (metal-containing compound, carbene, and alkylating agent) that are separately available but combine in situ. This segmentation allows each component to be optimized independently while simplifying the overall catalyst composition preparation, as the active catalyst forms automatically during the polymerization process without requiring pre-formed complex carbene complexes.

The alkylating agent acts as an intermediary that facilitates the reaction between the metal-containing compound and carbene to form the active nickel N-heterocyclic carbene complex in situ. This intermediary approach allows the catalyst to form directly within the catalyst composition without requiring external preparation, resolving the contradiction between achieving narrow molecular weight distribution and reducing catalyst composition complexity.