Phthalimide Production via Diammonium Phthalate Heating
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Solution Overview
Problem
Existing processes for producing phthalimide from phthalic acid or its salts result in low yields, are cost-intensive, and environmentally unfavorable, making them uneconomical and unsuitable for large-scale commercial production.
Innovation Solution
Heating diammonium phthalate in the presence of aromatic solvents at temperatures higher than 130°C to efficiently produce phthalimide, allowing for the recycling of phthalic acid salts during the ion exchanger production process, thereby overcoming the limitations of previous methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional processes (reaction of molten phthalic anhydride with ammonia or urea) are used to produce phthalimide, then phthalimide can be obtained, but the yields are low and the processes are cost-intensive and environmentally unfavorable
Solution Approach 1:
The invention changes the reaction parameters by using diammonium phthalate as the starting material instead of phthalic anhydride, and by conducting the reaction in aromatic solvents at temperatures above 130°C. These parameter changes lead to significantly improved yields (80-95%) and simplify the manufacturing process by eliminating the need for additional conversion steps from phthalic acid to phthalic anhydride.
Solution Approach 2:
The invention converts the previously problematic byproducts (monoammonium phthalate and diammonium phthalate) into the desired starting material for the reaction. By using diammonium phthalate directly, the process eliminates the need for costly and complex purification steps required in conventional methods, turning what were considered impurities into valuable reactants.
2Loss of substance
If phthalic acid salts solution from ion exchanger production is discarded, then the ion exchanger production process can proceed, but a large amount of waste is generated and valuable materials are lost
Solution Approach 1:
The invention implements a recovery process where phthalic acid salts solution, which would normally be discarded as waste from ion exchanger production, is converted into diammonium phthalate and then used as the starting material for phthalimide production. This closes the material loop, recovers valuable substances, and eliminates waste disposal problems.
Solution Approach 2:
The invention creates a multi-functional process where the phthalic acid salts solution serves dual purposes: it is both a byproduct of ion exchanger production and a precursor for phthalimide synthesis. This integrates two previously separate processes, allowing the same material to be utilized in multiple beneficial ways within the industrial ecosystem.
3Manufacturing precision
If conventional purification methods (washing with melt of pure phthalimide at up to 260°C) are used, then crude phthalimide can be purified, but the process requires very high temperatures and achieves only 62% final yield
Solution Approach 1:
The invention performs preliminary purification by using aromatic solvents to selectively dissolve and remove impurities before the main reaction completes. This preliminary action prevents impurity accumulation and eliminates the need for subsequent high-temperature washing steps, achieving both high purity and high yield under milder conditions.
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 achieves high yields of phthalimide, making it suitable for industrial production and enabling its recycled use in ion exchanger preparation, thus improving economic and environmental sustainability.
Implementation Method 1
Heating diammonium phthalate in the presence of aromatic solvents at temperatures higher than 130°C to efficiently produce phthalimide
Data Source
AI summary
The invention relates to a process to produce phthalimides by heating diammonium phthalate in the presence of aromatic solvents and to a process to produce phthalimides by heating diammonium phthalate in the presence of aromatic solvents for their recycled use during the ion exchanger production process. The diammonium phthalate is prepared by making use of the phthalic acid salts solution resulted from the ion exchanger production process.