Continuous Crystallization of Iodinated Aryls
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Solution Overview
Problem
Current industrial-scale purification of iodinated aryl compounds, such as X-ray contrast agents, faces challenges in achieving high purity and efficiency due to the limitations of batch crystallization processes, which are time-consuming and require large equipment, and often result in low purity due to high supersaturation.
Innovation Solution
A continuous crystallization process is employed, where a fraction of the solvent is removed during the crystallization of iodinated aryl compounds, enhancing supersaturation by adding anti-solvents, and optimizing conditions like temperature and pressure to maintain high purity and increase yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch crystallisation is performed at high supersaturation to promote crystal growth kinetics, then the crystallisation speed is improved, but the purity of the crystallised compounds deteriorates
Solution Approach 1:
The patent applies dynamic control of supersaturation through continuous addition of crude product solution and controlled solvent removal. The system transitions from static batch crystallisation to dynamic continuous crystallisation, where supersaturation is maintained within an optimal range (S=1.05-1.20) through real-time adjustment of feed rate and evaporation rate, resolving the contradiction between crystallisation speed and purity
Solution Approach 2:
The patent changes the operating parameters from high supersaturation (conventional batch) to controlled moderate supersaturation (continuous). By adjusting key parameters including supersaturation level, residence time, and continuous feed rate, the system achieves both high purity (>99.5%) and efficient crystallisation, directly resolving the purity-speed contradiction
2Manufacturing precision
If batch crystallisation is performed to achieve high purity, then the purity of crystallised compounds is improved, but the processing time and equipment size increase
Solution Approach 1:
The patent implements continuous crystallisation where crude product solution is continuously fed and solvent is continuously removed, maintaining steady-state operation. This continuous action eliminates idle time between batches and achieves high purity (>99.5%) within 2-4 hours of residence time, significantly reducing both time and equipment size compared to conventional batch processes
Solution Approach 2:
The system performs preliminary saturation adjustment by controlling the feed concentration and pre-heating the crude product solution before it enters the crystalliser. This preliminary preparation ensures that crystallisation proceeds efficiently from the start, reducing the overall processing time while maintaining high purity
3Productivity
If batch crystallisation is performed at elevated temperature to promote crystal growth, then the crystallisation kinetics are improved, but the equipment complexity and energy consumption increase
Solution Approach 1:
The patent utilizes controlled evaporation of solvent to induce supersaturation and crystallisation. By removing solvent through phase transition (liquid to vapor) at controlled rates, the system achieves efficient crystal growth without requiring excessive heating, maintaining energy efficiency while improving kinetics through continuous solvent removal
Solution Approach 2:
The patent replaces mechanical agitation and cooling systems with a simpler thermal evaporation-based continuous crystallisation system. The crystallisation is driven by solvent removal through evaporation rather than mechanical means, reducing equipment complexity and energy consumption while maintaining high productivity
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 increases yield per volume and time unit while maintaining or improving the purity of iodinated compounds, reducing equipment size requirements and processing time, and meeting stringent purity standards for in vivo use.
Implementation Method 1
purification by continuous crystallisation of the compound from a crude product in a solvent by removing at least a fraction of the solvent during the process
Implementation Method 2
purification by continuous crystallisation of the compound from a crude product in a solvent
Implementation Method 3
The crystallisation is also promoted by high supersaturation
Data Source
AI summary
The invention describes a process for the purification of iodinated aryl compounds where the purification is performed by continuous crystallization of a crude product in a solvent with removal of at least a fraction of the solvent. The continuous crystallization process is performed in one or more crystallizers at the boiling point of the content of the crystallizer.