Carbodiimide Production via Thiourea Desulfurization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing carbodiimides are inefficient due to low yields, require excessive bases, and generate harmful by-products, making them unsuitable for industrial-scale production, particularly when using thiourea as a precursor.
Innovation Solution
A process involving the reaction of an amine with carbon disulfide in the presence of a catalyst, followed by desulfurization with hypochlorite, and purification, which includes using a hydrogen sulfide capture agent and phase transfer catalysts to enhance yield and reduce environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a general method is used to obtain thiourea from amine and carbon disulfide, then the reaction can proceed, but the reaction is very slow and has low yield
Solution Approach 1:
The patent changes the reaction parameters by introducing a catalyst and controlling the reaction temperature between 50-150°C, which significantly accelerates the reaction rate between amine and carbon disulfide while maintaining high yield of thiourea
Solution Approach 2:
The patent uses a catalyst as an intermediary substance to facilitate the reaction between amine and carbon disulfide, enabling the reaction to proceed faster and more efficiently without being consumed in the process
2Productivity
If a large amount of base is used to promote the reaction, then the reaction can proceed, but the reaction takes long time
Solution Approach 1:
The patent optimizes the base concentration to a specific range rather than using a large amount, and combines it with catalyst and temperature control to achieve both fast reaction rate and short reaction time
3Ease of manufacture
If mercury oxide or lead oxide is used for oxidative desulfurization, then the method is simple, but it has great impact on environment
Solution Approach 1:
The patent replaces expensive and hazardous heavy metal oxides with cheaper, environmentally benign alternatives such as iodine or oxygen in basic medium, which can be used once and disposed of without environmental harm
Solution Approach 2:
The patent converts the harmful oxidative desulfurization process using toxic heavy metals into a beneficial process using environmentally friendly reagents that leave no harmful residue
4Ease of manufacture
If pyridine is used as solvent for oxidative desulfurization, then the method is applicable, but pyridine is expensive and difficult to recover
Solution Approach 1:
The patent replaces expensive pyridine solvent with water or alcohol, which are cheap, non-toxic, and easily separable, eliminating the need for complex recovery cycles
Solution Approach 2:
The patent changes the solvent system from organic pyridine to aqueous or alcoholic media, which fundamentally alters the reaction conditions but enables easier and more economical solvent disposal or recycling
5Productivity
If linear carbodiimide compound is used as sealant, then the reaction works, but foul odors are produced from volatile isocyanate by-product
Solution Approach 1:
The patent inverts the molecular structure from linear carbodiimide to cyclic carbodiimide, which fundamentally changes the reaction pathway to avoid isocyanate by-product formation while maintaining sealant effectiveness
Solution Approach 2:
The patent converts the harmful isocyanate by-product formation into a beneficial process where no volatile harmful substances are generated, improving work environment while maintaining functional effectiveness
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 the efficient production of high-purity carbodiimides with improved yield and reduced sulfur content, making it suitable for industrial applications without the need for expensive solvents or hazardous reagents.
Implementation Method 1
reacting an amine with carbon disulfide in the presence of a catalyst to obtain a thiourea
Implementation Method 2
desulfurizing the obtained thiourea with a hypochlorite in the presence of a basic compound to obtain a carbodiimide
Data Source
AI summary
A process for the production of a carbodiimide, comprising the steps of:(1) reacting an amine represented by the following formula(A) with carbon disulfide in the presence of a catalyst at a reaction temperature of 50 to 150° C. to obtain a thiourea represented by the following formula (B):(In the above formula (A), R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)(In the above formula (B), R is as defined in the above formula (A);(2) desulfurizing the obtained thiourea with a hypochlorite in the presence of a basic compound to obtain a carbodiimide represented by the following formula (C):(In the above formula (C), R is as defined in the above formula (A)); and(3) purifying the obtained carbodiimide.