Polyisobutylene Preparation via Isobutene Concentration Control
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Solution Overview
Problem
The existing processes for producing polyisobutylene from technical C4 hydrocarbon streams face challenges in maintaining a consistent high content of terminal double bonds, mean molecular weight, and low catalyst consumption, due to variations in the isobutene concentration and composition of these streams.
Innovation Solution
A process is developed where a technical C4 hydrocarbon stream containing 1-butene, 2-butene, and isobutene is combined with a stream of pure isobutene to maintain a steady-state isobutene concentration of at least 40% by weight, with a controlled variation of no more than 10%, ensuring consistent polymerization conditions and catalyst usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If technical C4 hydrocarbon streams with varying isobutene concentration are used directly for polymerization, then the elimination of upstream isobutene extraction is achieved, but the product specification (terminal double bond content, molecular weight, catalyst consumption) varies
Solution Approach 1:
The patent changes the concentration parameter of isobutene in the feed stream by blending technical C4 hydrocarbon streams with pure isobutene. This adjustment ensures the isobutene concentration remains within the optimal range of 30-60% by weight, maintaining consistent polymerization conditions and product quality while using readily available technical streams
Solution Approach 2:
Pure isobutene acts as an intermediary substance that mediates between the variable composition of technical C4 streams and the requirements for consistent polymerization. By introducing this intermediate pure component, the system achieves stable product specifications without requiring complete purification of the feed stream
2Ease of operation
If isobutene concentration in the feed stream varies, then operational simplicity is maintained, but the content of terminal double bonds and mean molecular weight of polyisobutylene varies
Solution Approach 1:
The patent implements a feedback control system where the isobutene concentration in the technical C4 stream is monitored, and the flow rates of both the technical stream and pure isobutene are continuously adjusted to maintain the combined stream within the target concentration range. This ensures stable terminal double bond content while maintaining operational simplicity
3Device complexity
If technical C4 streams with varying composition are used, then process integration is simplified, but catalyst consumption increases
Solution Approach 1:
By optimizing and controlling the isobutene concentration parameter in the feed stream through blending, the patent creates more favorable polymerization conditions that reduce side reactions and improve catalyst efficiency. This leads to lower catalyst consumption while maintaining the simplified process integration of using technical C4 streams
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
This approach results in polyisobutylene with a high content of terminal double bonds (>50%), consistent mean molecular weight, and low residual monomers and halogen content, enhancing the operational stability and product quality.
Implementation Method 1
polymerizing isobutene in the presence of a polymerization catalyst customary therefor
Data Source
AI summary
Continuous preparation of polyisobutylene having a content of terminal double bonds of more than 50% by polymerizing isobutene in the presence of a polymerization catalyst customary therefor, by combining a technical 1-butene-, 2-butene- and isobutene-containing C4 hydrocarbon stream together with a stream of pure isobutene and feeding them into the reaction zone in such a way that the steady-state concentration of the isobutene in the combined stream at the feed point of the combined stream into the reaction zone has an average value of at least 40% by weight, and a polymerization plant therefor.