Hydroformylation Buffer Neutralizes Acidic By-products
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Solution Overview
Problem
Rhodium-phosphite hydroformylation processes face issues with catalyst inhibition and ligand degradation due to the formation of acidic by-products, which are not effectively addressed by existing phosphorous-based buffers, especially under environmental constraints limiting phosphorous content in effluent streams.
Innovation Solution
A process involving an aqueous buffer solution with a salt of an unsaturated aliphatic carboxylic acid is used to neutralize phosphorus acidic compounds, effectively removing acidic by-products and promoting the hydrolysis of diorganophosphite by-products without impacting the hydroformylation process, utilizing a buffer that buffers in the pH range of 6 to 8.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphorous-based buffers (e.g., sodium phosphate) are used to neutralize acidic by-products, then catalyst inhibition is reduced and ligand stability is improved, but phosphorous content in effluent increases violating environmental limits
Solution Approach 1:
The patent changes the chemical composition parameter of the buffer from phosphorous-based (phosphate) to non-phosphorous based (maleate/fumarate salts), maintaining the buffering function in pH range 6-8 while eliminating phosphorous discharge to meet environmental limits
Solution Approach 2:
The patent employs maleate/fumarate buffers that can be easily disposed of or degraded compared to phosphate buffers, allowing for effective acid neutralization without the environmental persistence and regulatory issues associated with phosphorous in effluent streams
2Object-generated harmful factors
If maleic acid is added to destroy phosphorous-based ligands via Michael addition, then residual maleic acid removal is desirable, but continuous extraction with traces of maleate significantly impacts ligand degradation
Solution Approach 1:
The patent converts the potentially harmful effect of maleate (which can cause ligand degradation via Michael addition) into a beneficial buffering system by using maleate/fumarate salts that provide effective acid neutralization in pH 6-8 without the detrimental Michael addition reactions, thus eliminating the harm while retaining the benefit of acid control
Solution Approach 2:
The patent uses maleate/fumarate salts as intermediary buffering agents that mediate the acid-base chemistry effectively without directly interacting with the ligand in a harmful manner, avoiding the Michael addition pathway while still providing the necessary pH control to prevent ligand degradation
3Object-generated harmful factors
If phosphorous-free buffers (maleates/fumarates) are used instead of phosphates, then environmental limits on phosphorous are met, but α,β-unsaturated carbonyls act as catalyst inhibitors
Solution Approach 1:
The patent changes the buffer chemistry from phosphorous-based to non-phosphorous based (maleate/fumarate), meeting environmental phosphorous limits while the pH control in range 6-8 prevents catalyst inhibition by α,β-unsaturated carbonyls through proper acid-base neutralization
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 approach stabilizes the organophosphorous ligand and metal-organophosphorous ligand complex, reduces degradation, and maintains catalytic activity, offering a non-phosphorous based buffering solution that effectively manages acidity and extends ligand life without significant detrimental effects on the hydroformylation process.
Implementation Method 1
contacting a reaction fluid containing (a) a phosphorus acidic compound... with an aqueous buffer solution to neutralize at least some amount of the phosphorus acidic compound
Implementation Method 2
promoting the preferential hydrolysis of diorganophosphite by-products
Data Source
AI summary
A process comprising contacting a reaction fluid, which contains at least one phosphorus acidic compound, with a buffer solution to neutralize at least some amount of the phosphorus acidic compound, wherein the buffer solution comprises at least one salt of an unsaturated aliphatic carboxylic acid.