Continuous Catalytic System Preparation for Diene Polymerization
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Solution Overview
Problem
The existing batch process for preparing catalytic systems for conjugated diene polymerization is inefficient due to long cycle times, difficulty in controlling exothermicity, and reduced concentration of rare-earth elements, leading to safety concerns and reduced catalytic activity, as well as challenges in achieving reproducibility and coupling with continuous polymerization processes.
Innovation Solution
A continuous process for preparing a catalytic system using a feed line with dynamic mixers for alkylation and halogenation-ageing, allowing for controlled exothermicity and higher rare-earth element concentrations, enabling the production of catalytic systems with improved activity and microstructural characteristics similar to those produced in batch mode, while allowing for flexible modulation of the alkylating agent/salt ratio and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the concentration of rare-earth elements is increased in batch mode, then catalytic activity is improved, but exothermicity becomes difficult to control and safety is compromised
Solution Approach 1:
The patent transitions from batch mode to continuous mode for catalytic system preparation. In continuous mode, reactants are continuously fed through a series of dynamic mixers allowing sustained reaction with better heat dissipation. This enables higher rare-earth element concentrations (improving catalytic activity) while maintaining controlled exothermicity through continuous flow and heat exchange, resolving the contradiction between activity and safety.
Solution Approach 2:
The continuous preparation process segments the reaction into multiple stages using a series of dynamic mixers (typically 3-5 mixers in sequence). Each mixer handles a portion of the alkylation and halogenation steps, distributing the exothermic load across multiple small reaction zones rather than one large batch reactor. This segmentation allows better temperature control while maintaining high catalyst concentration.
2Productivity
If batch mode is used for catalytic system preparation, then cycle time is long and productivity is reduced, but reactor volume can be kept relatively large
Solution Approach 1:
The patent implements continuous preparation of the catalytic system instead of batch processing. Reactants are continuously fed through the dynamic mixer train, eliminating the start-stop nature of batch operations. This continuous operation dramatically reduces cycle time (improving productivity) while the modular nature of the dynamic mixer system allows compact reactor configuration with smaller individual volumes, resolving the contradiction between productivity and reactor volume.
3Manufacturing precision
If batch process is used, then reproducibility is difficult to achieve, but flexibility in operation is maintained
Solution Approach 1:
The continuous preparation process incorporates precise flow control and mixing parameters that can be consistently maintained throughout operation. The dynamic mixer system provides uniform mixing conditions and controlled residence times that ensure reproducible catalytic system properties batch after batch. Meanwhile, the modular design allows easy adjustment of flow rates and mixing parameters to adapt to different production requirements, resolving the contradiction between reproducibility and flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The continuous process achieves efficient and reproducible production of catalytic systems with higher rare-earth element concentrations, improved safety, and reduced reactor volumes, resulting in cost-effective and flexible operation with enhanced polymerization outcomes.
Implementation Method 1
in a third step of alkylation, said alkylating agent is added to the suspension obtained at the end of said second step in order to obtain an alkylated salt
Implementation Method 2
in a fourth step of halogenation, said halogen donor is added to said alkylated salt, producing a highly exothermic reaction of formation of a prepolymer
Implementation Method 3
producing a highly exothermic reaction of formation of a prepolymer of said conjugated diene
Implementation Method 4
in a fifth step of ageing, the mixture thus obtained is maintained at a constant temperature of approximately 60° C. for one to two hours
Data Source
AI summary
The present invention relates to a process for the continuous preparation of a catalytic system that can be used for the polymerization of at least one conjugated diene monomer, said catalytic system being based on at least:a preforming conjugated diene;an organic phosphoric acid salt of one or more rare-earth metal(s), said salt being in suspension in at least one saturated aliphatic or alicyclic and inert hydrocarbon-based solvent;an alkylating agent comprising an alkylaluminium having the formula AlR3 or HAlR2; anda halogen donor comprising an alkylaluminium halide;characterized in that it comprises successively in one line (L):(i) a reaction between the preforming conjugated diene, with the solution of the salt of rare-earth element(s) and the alkylating agent, with the alkylation reaction being carried out for a characteristic minimum period of at least 5 minutes in an alkylation reactor (30) composed of at least one well-mixed dynamic mixer;(ii) the addition of said halogen donor to the mixture obtained in (i), in order to produce a reaction for the halogenation-ageing of the preformed catalytic system and to continuously produce said preformed catalytic system at the outlet of said line (L).