Regioselective Cellulose Ester Synthesis in Halide Ionic Liquids
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Solution Overview
Problem
Current methods for producing cellulose esters in ionic liquids are inefficient due to high costs and residual metal, sulfur, and halide contamination, and existing processes do not effectively recycle ionic liquids.
Innovation Solution
A process involving the use of halide ionic liquids for dissolving cellulose, followed by acylation and precipitation to produce regioselectively substituted cellulose esters, with the option to recycle the ionic liquid for further cellulose dissolution, reducing contamination and processing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce cellulose esters in ionic liquids, then cellulose esters can be produced, but the process is costly and produces residual metal, sulfur, and halide contamination
Solution Approach 1:
The patent extracts and removes residual contaminants (metal, sulfur, and halide) from the ionic liquid system through selective separation processes. The method involves treating the ionic liquid with specific reagents that bind to and remove these contaminants, thereby purifying the ionic liquid for reuse and eliminating harmful residues in the final cellulose ester product.
Solution Approach 2:
The patent changes the chemical parameters of the ionic liquid system by introducing specific purifying agents and adjusting reaction conditions. This includes modifying pH levels, adding chelating agents to bind metal ions, and using filtration methods with specific pore sizes to remove particulate contaminants, thereby transforming the ionic liquid from a contaminated state to a purified state.
2Ease of manufacture
If ionic liquids are used as solvents in cellulose ester production, then cellulose dissolution and esterification can be achieved, but the high cost of ionic liquids makes the process economically unfeasible without recycling
Solution Approach 1:
The patent implements a recycling system where the ionic liquid is recovered from the cellulose ester production process through separation techniques. The used ionic liquid undergoes purification to remove contaminants and is then reused as a solvent for subsequent batches, thereby recovering the expensive substance and eliminating the need for continuous replacement.
Solution Approach 2:
The patent creates a self-sustaining process where the ionic liquid system serves itself by being continuously regenerated and reused. The purification steps are integrated into the production workflow, allowing the ionic liquid to be automatically recovered and prepared for reuse without requiring external intervention or disposal, thereby making the process economically viable.
3Productivity
If existing processes are used for ionic liquid production, then ionic liquids can be synthesized, but residual metals, sulfur, and halides remain due to the use of halide and sulfur intermediates or metal oxide catalysts
Solution Approach 1:
The patent converts the harmful residual contaminants into removable byproducts through chemical treatment. Specifically, metal ions are converted to insoluble hydroxides or chelates, sulfur compounds are oxidized to removable forms, and halide ions are precipitated or exchanged. This transforms the harmful residuals present during synthesis into easily separable substances that can be removed, thereby maintaining production efficiency while eliminating contamination.
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 cellulose esters with reduced residual contaminants and lower processing costs, allowing for the recycling of ionic liquids and improving the overall efficiency of cellulose ester production.
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
The resulting process enables the efficient production of cellulose esters
Data Source
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.