Regioselective Cellulose Ester Production via Halide Ionic Liquid Recycling
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Solution Overview
Problem
The production of ionic liquids for use in cellulose esterification processes is hindered by high costs and inefficiencies in recycling, as well as the presence of residual metals, sulfur, and halides in existing methods, which affect the quality and feasibility of cellulose ester production.
Innovation Solution
A process involving the use of halide ionic liquids for dissolving cellulose, followed by esterification with acylating reagents, and subsequent separation and recycling of the ionic liquid, allowing for the production of regioselectively substituted cellulose esters with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce ionic liquids, then ionic liquids can be obtained, but residual metals, sulfur, and halides are present affecting product quality
Solution Approach 1:
The patent extracts and removes harmful residual metals, sulfur, and halides from the ionic liquid through purification steps including filtration and washing processes, thereby obtaining high-purity ionic liquid suitable for cellulose esterification
Solution Approach 2:
The patent changes the purity parameter of the ionic liquid by implementing multiple purification stages, transforming the ionic liquid from a crude product containing impurities to a refined product meeting strict purity requirements for pharmaceutical applications
2Manufacturing precision
If ionic liquids are used in cellulose esterification, then regioselectively substituted cellulose esters can be produced, but the process cost increases due to ionic liquid expense
Solution Approach 1:
The patent recovers and reuses the ionic liquid catalyst after the esterification reaction through separation and purification steps, converting it from a consumable expense to a recyclable catalyst, thereby reducing overall production costs while maintaining regioselectivity
Solution Approach 2:
The ionic liquid serves a dual function as both reaction medium and catalyst, and its self-recycling capability eliminates the need for continuous external supply, reducing operational costs
3Productivity
If ionic liquids are recycled, then costs are reduced, but recycling efficiency is insufficient in existing methods
Solution Approach 1:
The patent implements a feedback mechanism where the recycled ionic liquid is characterized and its quality is monitored, and this information feeds back into the purification process optimization to maintain high recycling efficiency and minimize losses
Solution Approach 2:
The patent uses composite separation systems combining multiple purification techniques to achieve high-efficiency ionic liquid recycling with minimal energy loss and maximum recovery rate
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 process enables the efficient production of regioselectively substituted cellulose esters with specific Rth values, enhancing their suitability for applications such as compensation films in liquid crystalline displays, while also recycling and purifying the ionic liquids to reduce waste and costs.
Implementation Method 1
introducing a reaction medium comprising cellulose, a halide ionic liquid and a binary component into an esterification zone
Implementation Method 2
combining at least one acylating reagent with said reaction medium in said esterification zone to esterify at least a portion of said cellulose
Implementation Method 3
contacting said acylated cellulose solution with a non-solvent to cause at least a portion of said cellulose ester to precipitate
Data Source
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AI summary
This invention relates to novel compositions comprising regioselectively substituted cellulose esters. One aspect of the invention relates to processes for preparing regioselectively substituted cellulose esters from cellulose dissolved in ionic liquids. Another aspect of the invention relates to the utility of regioselectively substituted cellulose esters in applications such as protective and compensation films for liquid crystalline displays.