Quantifying Acid Sites in Ionic Liquids via Silane Reaction
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Solution Overview
Problem
There is a need for methods to quantify the acidity of ionic liquids, particularly the Brønsted acid sites, as existing methods are destructive or provide limited information due to the formation of amine-AlCl3 complexes, and direct contact with basic reagents deactivates the ionic liquid.
Innovation Solution
A method involving the use of silane or borane compounds to react with Brønsted acid sites in acidic ionic liquids, forming silyl or boryl compounds that can be measured in the hydrocarbon phase, allowing for the determination of the number of Brønsted acid sites without deactivating the ionic liquid, and enabling the regeneration and reuse of the silane or borane compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If basic reagents (e.g., amines) are used to quantify acid sites in ionic liquids, then the acid sites can be neutralized and measured, but the ionic liquid becomes deactivated due to formation of amine-AlCl3 complexes
Solution Approach 1:
The patent introduces water as an intermediary substance that selectively reacts with Brønsted acid sites to form hydronium ions. This intermediary approach allows quantification of acid sites through titration with a base while preventing direct contact between the base and the ionic liquid catalyst, thus avoiding deactivation. The water acts as a mediator that transfers the neutralization reaction away from the sensitive ionic liquid system.
Solution Approach 2:
The patent segments the measurement process into two distinct phases: first, water reacts with acid sites in the ionic liquid to form hydronium ions; second, a base titrant reacts with the hydronium ions in the aqueous phase. This segmentation isolates the ionic liquid from direct contact with the base, allowing accurate measurement without catalyst deactivation.
2Loss of information
If existing quantification methods are used, then acid site information can be obtained, but the ionic liquid is destroyed or deactivated in the process
Solution Approach 1:
Water serves as an intermediary that enables the quantification of acid sites without destroying the ionic liquid. The water selectively interacts with Brønsted acid sites through proton transfer, forming hydronium ions that can then be titrated. This intermediary mechanism preserves the ionic liquid structure while providing complete acid site quantification information.
Solution Approach 2:
The ionic liquid itself provides the information needed for quantification through its own Brønsted acid sites reacting with water. The acid sites in the ionic liquid automatically serve as the source of protons for the titration reaction, eliminating the need for external reagents that might damage the catalyst.
3Productivity
If more acid sites are present in the ionic liquid, then catalytic activity increases, but conjunct polymer formation increases leading to catalyst deactivation
Solution Approach 1:
The patent establishes a feedback mechanism by providing a method to accurately measure acid site concentration in the ionic liquid. This quantitative information allows operators to optimize the amount of ionic liquid or adjust reaction conditions to maintain high catalytic activity while staying below the threshold where conjunct polymer formation causes deactivation. The feedback loop enables precise control of catalyst performance and longevity.
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 method allows for non-destructive quantification of Brønsted acid sites in ionic liquids, enabling effective control of acid levels in hydrocarbon conversion processes, ensuring the appropriate acid level in fresh or regenerated ionic liquids, and preventing the formation of deactivating complexes, thus maintaining the ionic liquid's activity.
Implementation Method 1
Brønsted acid sites in the acidic ionic liquid react with the silane or borane compound
Data Source
AI summary
A method of quantifying an amount of Brønsted acid sites in an acidic ionic liquid is described. The method involves adding a known amount of at least one silane or borane compound to the acidic ionic liquid being analyzed. The Brønsted acid sites in the acidic ionic liquid react with the silane or borane compound to form a silyl or boryl compound, resulting in an ionic liquid phase and a hydrocarbon phase which contains the silyl or boryl compound. The amount of silyl or boryl compound in the hydrocarbon phase is measured. From the measured amount of silyl or boryl compound formed, the amount of Brønsted acid sites can be determined.