Potassium 5-iodo-2-carboxybenzene sulfonate synthesis via in situ diazotization
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Solution Overview
Problem
Existing methods for preparing 5-iodo-2-carboxybenzenesulfonate require the isolation of diazonium salts, which are prone to decomposition, and involve the use of toxic carbon monoxide, large amounts of organic solvents like acetonitrile, and homogeneous palladium catalysts that are difficult to recycle, leading to low yields and environmental concerns.
Innovation Solution
A method involving the diazotization of 5-amino-2-carboxybenzene sulfonate with KNO2 in the presence of HCl, followed by reaction with KI, eliminates the need for isolated diazonium salt isolation, reduces the use of organic solvents, and avoids the use of carbon monoxide and homogeneous palladium catalysts, allowing for high-yield production of potassium 5-iodo-2-carboxybenzene sulfonate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diazonium salt isolation is performed, then reaction intermediate can be separated, but decomposition risk increases and process complexity increases
Solution Approach 1:
The patent combines the diazotization step and the subsequent reaction with KI into a one-pot process, eliminating the isolation step. The diazonium salt is generated in situ and immediately reacted with KI to form the iodo compound, avoiding decomposition risks and simplifying the process.
Solution Approach 2:
The diazonium salt is formed as an intermediate that is immediately consumed in the subsequent reaction with KI. By preparing the diazonium salt in advance within the same reaction vessel and directly reacting it with KI, the method avoids isolation while maintaining reaction efficiency.
2Ease of manufacture
If homogeneous palladium catalyst is used, then carbonylation reaction can be catalyzed, but catalyst recycling becomes difficult and cost increases
Solution Approach 1:
The patent removes the homogeneous palladium catalyst from the process entirely. Instead of using Pd-catalyzed carbonylation, the method employs a direct diazotization followed by KI reaction, eliminating the need for expensive and difficult-to-recycle homogeneous catalysts.
3Ease of manufacture
If carbon monoxide is used, then carbonylation can occur, but toxicity increases and safety risks increase
Solution Approach 1:
The patent eliminates the use of toxic CO by replacing the carbonylation pathway with a diazotization-KI reaction pathway. This substitution removes the harmful factor while achieving the desired iodo compound synthesis through an alternative chemical route.
4Ease of operation
If large amounts of organic solvent are used, then reaction can proceed smoothly, but solvent waste increases and environmental impact increases
Solution Approach 1:
The patent changes the reaction parameters by using water as the solvent instead of large amounts of organic solvents like acetonitrile. The diazotization and KI reaction proceed efficiently in aqueous medium, reducing organic solvent waste and environmental impact while maintaining reaction smoothness.
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 provides a cleaner, high-yield production of potassium 5-iodo-2-carboxybenzene sulfonate without the need for diazonium salt isolation, reduces solvent usage, and avoids toxic reagents, making it suitable for large-scale production.
Implementation Method 1
compound of formula (2) is reacted in a reaction REAC1 with KNO2 in the presence of HCl providing the diazonium salt of compound of formula (2)
Implementation Method 2
the diazonium salt of compound of formula (2) is reacted in a reaction REAC2 with KI providing compound of formula (3)
Data Source
AI summary
The invention discloses a method for the preparation of potassium 5-iodo-2-carboxybenzene sulfonate by diazotization of 5-amino-2-carboxybenzene sulfonate and subsequent reaction with KI.