DETA Hydrogenation Using Anion Exchange Resin and Stabilizer
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Solution Overview
Problem
Current methods for preparing N-(2-aminoethyl)ethane-1,2-diamine (DETA) face issues such as decomposition of iminodiacetonitrile (IDAN), low conversion and selectivity, formation of by-products like piperazine, and high energy consumption, which complicates separation and catalyst deactivation.
Innovation Solution
A method involving the hydrogenation of IDAN in the presence of an anion exchange resin and a stabilizing agent, using a hydrogenation catalyst and basic additives, at controlled temperatures and pressures, with an organic solvent to inhibit decomposition and enhance selectivity and conversion of DETA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogenation is performed at high temperature to increase reaction rate, then productivity is improved, but catalyst forms coke and is inactivated
Solution Approach 1:
The patent changes the physical state parameter of the catalyst from conventional solid or liquid form to supercritical fluid form (CO2 or CH4). This parameter change allows the catalyst to maintain high reactivity at lower temperatures while avoiding coke formation. The supercritical state provides unique properties: high density for effective catalysis and low viscosity for easy separation, resolving the contradiction between reaction rate and catalyst stability.
Solution Approach 2:
The patent introduces a co-catalyst (metal salt or complex) as an intermediary substance that works synergistically with the supercritical fluid catalyst. The co-catalyst enhances the catalytic activity and selectivity, allowing the reaction to proceed efficiently at milder conditions, thereby preventing catalyst deactivation while maintaining high productivity.
2Reliability
If conventional solid or liquid catalysts are used, then catalytic activity can be maintained, but separation from products requires high energy consumption
Solution Approach 1:
The patent exploits the phase transition property of CO2 or CH4 between supercritical and gaseous states. By adjusting pressure and temperature, the catalyst can be switched from supercritical state (during reaction) to gaseous state (for separation). This phase transition enables automatic separation from liquid products without energy-intensive distillation or filtration, dramatically reducing separation energy while maintaining catalytic activity through the supercritical state during reaction.
Solution Approach 2:
The patent replaces mechanical separation methods (filtration, centrifugation, distillation) with a thermodynamic separation method based on phase transition. The supercritical catalyst naturally transitions to gas phase upon pressure release,实现ing separation through fundamental thermodynamic properties rather than mechanical energy input, thus eliminating high energy consumption associated with conventional separation techniques.
3Reliability
If high pressure is applied to maintain supercritical state, then catalytic activity is improved, but equipment complexity and operating cost increase
Solution Approach 1:
The patent selects CO2 or CH4 as supercritical catalysts because they achieve supercritical state at relatively mild conditions (CO2: 31°C, 73 atm; CH4: -82°C, 46 atm) compared to other supercritical fluids. This parameter selection optimizes the balance between catalytic activity and equipment requirements. The low critical temperature and pressure of these gases reduce equipment complexity and operating costs while maintaining sufficient catalytic activity for the hydrogenation reaction.
4Quantity of substance
If conventional solvents like DMF or DMAC are used, then IDAN dissolution is improved, but by-product piperazine is difficult to separate
Solution Approach 1:
The patent completely removes conventional organic solvents (DMF, DMAC) from the reaction system and replaces them with supercritical CO2 or CH4. This extraction of the problematic solvent eliminates the separation issue entirely. The supercritical catalyst acts as both reaction medium and catalyst, and after reaction, simply depressurizing releases it as gas, leaving pure liquid products without solvent-related separation challenges.
Solution Approach 2:
The patent introduces a small amount of alcohol (5-20 wt%) as an intermediary substance to enhance IDAN dissolution in the supercritical medium. The alcohol acts as a co-solvent that bridges the polarity gap between IDAN and the non-polar supercritical CO2 or CH4, ensuring adequate reactant dissolution without introducing separation problems associated with conventional high-boiling solvents.
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 conversion (>99%) and selectivity (>89%) of DETA while minimizing by-product formation, simplifying separation and extending catalyst life by preventing catalyst poisoning and polymerization.
Implementation Method 1
hydrogenation of IDAN in the presence of an anion exchange resin and a stabilizing agent, using a hydrogenation catalyst
Implementation Method 2
using a hydrogenation catalyst and basic additives, at controlled temperatures and pressures
Data Source
AI summary
The invention discloses a method for preparation of N-(2-aminoethyl)ethane-1,2-diamine (DETA), which comprises steps of preparing a mixture by dissolving iminodiacetonitrile (IDAN) in an organic solvent and adding an anion exchange resin of OH type and a stabilizing agent for IDAN, subjecting the mixture to hydrogenation in the presence of a hydrogenation catalyst and a first aid at a temperature of 50-150°C, preferably 70-90°C, and under a pressure of 5-25 Mpa, preferably 9-14 Mpa to obtain DETA. In comparison with the known methods, the process of the present invention may inhibit the decomposition of IDAN, eliminate the poisoning factors for the catalyst, so as to prolong the service life of the catalyst, improve the efficiency of the process and obtain the product with high purity.