Carboxylation Catalyst System for Unsaturated Acid Salts
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Solution Overview
Problem
The industrial production of α,β-ethylenically unsaturated carboxylic acid salts from CO2 and alkenes is hindered by thermodynamic limitations, unfavorable equilibria, and the use of potentially harmful fluorine-substituted phenoxide bases, which complicate purification and lead to emissions of harmful pollutants.
Innovation Solution
A catalytic process involving a transition metal complex, an alkoxide, and an organic solvent that is incompletely miscible with water at specific temperatures, facilitating the formation of α,β-ethylenically unsaturated carboxylic acid salts with improved catalytic turnover and reduced environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sodium hydroxide is used as the base to form sodium acrylate, then the reaction is thermodynamically favored, but the base is immediately consumed by side reaction with CO2 to form sodium carbonate or sodium bicarbonate
Solution Approach 1:
The patent introduces a metal complex (nickel, palladium, or platinum) as an intermediary catalyst that mediates the reaction between CO2 and the base. The metal complex forms a metallalactone intermediate that decomposes to release the desired carboxylic acid salt without direct consumption of the base by CO2, thus resolving the contradiction between high yield and base stability
Solution Approach 2:
The patent replaces the conventional base-promoted mechanism with a metal-catalyzed mechanism. Instead of using strong bases like sodium hydroxide that directly react with CO2, the system uses metal complexes to facilitate the carboxylation reaction, substituting the chemical mechanism to avoid the harmful side reaction while maintaining productivity
2Reliability
If less nucleophilic bases are used to prevent side reactions, then the base stability improves, but the acrylate formation is kinetically inhibited
Solution Approach 1:
The patent replaces the base-promoted reaction mechanism with a metal-catalyzed mechanism. The metal complex (nickel, palladium, or platinum) activates CO2 and facilitates its addition to the alkene, enabling the use of less nucleophilic bases while maintaining high reaction rates through catalytic activation rather than relying on base nucleophilicity
Solution Approach 2:
The patent changes the reaction mechanism from base-promoted to metal-catalyzed, fundamentally altering how the reaction proceeds. This parameter change allows the system to use weaker bases while maintaining productivity, as the metal complex provides the necessary activation energy and catalytic pathway independent of base strength
3Productivity
If fluorine-substituted phenoxide bases are used to achieve high catalytic turnover, then the productivity improves, but the purification becomes complicated and harmful pollutants are emitted
Solution Approach 1:
The patent employs simple, readily available bases like sodium hydroxide or potassium hydroxide instead of complex fluorine-substituted phenoxide bases. These conventional bases are easier to handle, cheaper, and do not require complex purification or pose environmental hazards, while still achieving high catalytic turnover through the metal complex catalyst system
Solution Approach 2:
The patent converts the previously harmful fluorine-substituted phenoxide bases into beneficial conventional bases. By using metal complex catalysis, the system enables the use of simple, environmentally benign bases like NaOH or KOH that achieve the same catalytic turnover without the harmful emissions and purification complications associated with fluorinated phenoxides
4Ease of manufacture
If stoichiometric coupling of CO2 and ethene is used, then the reaction can proceed, but the nickelalactone intermediates are particularly stable and do not spontaneously decompose
Solution Approach 1:
The patent introduces dynamic conditions to the reaction system, specifically using elevated temperatures (80-200°C) and pressures (1-100 bar) to promote the decomposition of stable nickelalactone intermediates. These dynamic conditions provide the energy needed to break the stable intermediate complexes and release the desired acrylate product, transforming a static stoichiometric reaction into a dynamic catalytic process with high turnover
Solution Approach 2:
The patent changes the reaction parameters from standard stoichiometric conditions to elevated temperature and pressure conditions. This parameter change provides the thermal energy necessary to decompose the stable nickelalactone intermediates and drive the catalytic cycle forward, enabling high catalytic turnover while maintaining reaction feasibility
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 efficient production of α,β-ethylenically unsaturated carboxylic acid derivatives on an industrial scale with high catalytic turnover, avoiding the use of harmful compounds and simplifying purification by using hydrophobic amides or ureas as solvents, thus reducing environmental concerns.
Implementation Method 1
a catalytic process for preparing an α,β-ethylenically unsaturated carboxylic acid salt from an alkene, carbon dioxide, and an alkoxide
Implementation Method 2
the organic solvent being incompletely miscible with water at a pressure of 1 bar at at least one temperature T and selected from amides and ureas
Data Source
AI summary
The present invention relates to a catalytic process for preparing an α,β-ethylenically unsaturated carboxylic acid salt, comprising contacting an alkene and carbon dioxide with a carboxylation catalyst being a transition metal complex, an alkoxide, and an organic solvent, to obtain an α,β-ethylenically unsaturated carboxylic acid salt, the organic solvent being incompletely miscible with water at a pressure of 1 bar at at least one temperature T and selected from amides and ureas, T being a temperature in the range from 10° C. to 90° C.