IPMS Copolymer Purification via Halogenic Scavenger
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Solution Overview
Problem
The existing processes for producing isobutylene-paramethylstyrene (IPMS) copolymers face challenges in managing excessive accumulation of free paramethylstyrene (pMS) monomers, leading to unacceptably high stearic acid concentrations in finished brominated copolymers.
Innovation Solution
A process involving the use of a halogenic scavenger to react with unreacted alkylstyrene monomers in the absence of free radical initiators, converting them into halogenic alkylstyrene compounds that can be easily removed, thereby reducing the concentration of free pMS monomers in the copolymer slurry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If continuous copolymer production is maintained to keep steady low level of pMS monomers in slurry, then stearic acid concentration in finished copolymer remains low, but free pMS monomers accumulate in bulk hexane solvent leading to unacceptably high levels in finished product
Solution Approach 1:
The patent extracts and removes free pMS monomers from the hexane solvent system through a dedicated removal step before recycling the hexane. This prevents the accumulation of free pMS monomers in the bulk solvent while maintaining continuous production conditions that keep stearic acid levels low.
Solution Approach 2:
The patent introduces an intermediary treatment step (such as adsorption or chemical reaction) that mediates between the continuous production process and the hexane recycling system. This intermediary mechanism captures free pMS monomers from the hexane before they can accumulate to problematic levels, allowing both continuous operation and low stearic acid concentrations.
2Quantity of substance
If plant switches to production of BIMS copolymers to brominate excess pMS monomers, then free pMS monomers are converted, but they may not be fully hydrolyzed and removed due to excessive concentration leading to high stearic acid
Solution Approach 1:
The patent applies preliminary action by removing free pMS monomers from the hexane solvent before the bromination process. This pre-removal step ensures that when bromination occurs, the concentration of free pMS monomers is controlled and can be fully hydrolyzed and removed, preventing excessive stearic acid formation in the finished product.
Solution Approach 2:
The patent segments the process into distinct stages: (1) continuous copolymer production maintaining low pMS levels in slurry, (2) free pMS monomer removal from hexane solvent, (3) controlled bromination, and (4) hydrolysis. This segmentation allows each step to be optimized independently, ensuring complete pMS conversion without excessive stearic acid accumulation.
3Adaptability or versatility
If non-brominated IPMS copolymers are produced allowing unreacted pMS monomers to accumulate in bulk hexane, then production flexibility is maintained, but remaining free pMS stays in copolymer slurry at unacceptably high level
Solution Approach 1:
The patent introduces an intermediary free pMS monomer removal step that operates between copolymer production and product finishing. This intermediary mechanism selectively removes free pMS monomers from the hexane solvent regardless of whether the final product will be brominated or non-brominated, maintaining production flexibility while ensuring acceptable free pMS levels in all finished products.
Solution Approach 2:
The patent implements a universal free pMS monomer removal step that serves both brominated and non-brominated copolymer production lines. This multi-functional approach allows the same process to maintain low free pMS levels in both product types, providing production flexibility without compromising product quality.
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 allows for the production of cement compositions with isoolefin-alkylstyrene copolymers that are substantially free of alkylstyrene monomers, achieving consistently low levels of stearic acid in the finished rubber products and addressing industrial hygiene concerns.
Implementation Method 1
reacting a halogenic scavenger with the unreacted alkylstyrene monomer in an absence of a free radical initiator in order to form a halogenic alkylstyrene compound without altering the isoolefin-alkylstyrene copolymer
Implementation Method 2
replacing the diluent with a solvent
Implementation Method 3
removing the halogenic alkylstyrene compound from the slurry to form the cement composition substantially free of the alkylstyrene monomer
Data Source
AI summary
A process for preparing a cement composition comprising an isoolefin-alkylstyrene copolymer and substantially free of an alkylstyrene monomer is described herein. The process comprises reacting the isoolefin monomer with at least a portion of the alkylstyrene monomer in a diluent to form an isoolefin-alkylstyrene copolymer, replacing the diluent with a solvent, reacting a halogenic scavenger with the unreacted alkylstyrene monomer in an absence of a free radical initiator in order to form a halogenic alkylstyrene compound without altering the isoolefin-alkylstyrene copolymer, and removing the halogenic alkylstyrene compound from the slurry to form the cement composition substantially free of the alkylstyrene monomer. Also disclosed herein is a composition comprising an isoolefin-alkylstyrene copolymer and an alkylstyrene monomer comprising a concentration less than about 20 ppm.