Ethyleneamine Production via Liquid-Phase MEG Amination
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Solution Overview
Problem
Current processes for preparing ethylenediamine (EDA) face challenges such as complex handling of ethylene oxide, formation of unwanted by-products, and inefficient catalyst performance, particularly in the liquid phase.
Innovation Solution
A process involving the reaction of monoethylene glycol (MEG) with ammonia in the liquid phase, using a heterogeneous catalyst obtained by reducing a catalyst precursor. The catalyst precursor is prepared by contacting a mixture of Sn, Cu, and Ni with a soluble Re compound, enhancing selectivity for linear amination products like MEA and EDA while reducing the formation of cyclic and higher ethanolamines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the reaction of MEG with ammonia is conducted in the liquid phase using conventional catalysts, then the process avoids the complexity of EO handling, but the catalyst activity and selectivity are insufficient, leading to low productivity and high by-product formation
Solution Approach 1:
The patent employs a composite catalyst comprising multiple metal components (Cu, Ni, and Zn or Al) supported on a porous carrier. This composite structure combines the benefits of different metals: Cu and Ni provide catalytic activity for C-N bond formation, while Zn or Al enhance selectivity and structural stability. The porous support material provides high surface area and appropriate pore structure for liquid-phase reactant access, thereby achieving high productivity and selectivity in the liquid-phase amination of MEG.
Solution Approach 2:
The patent optimizes multiple reaction parameters including temperature (150-350°C), pressure (1-30 bar), and catalyst composition ratios to maximize productivity. By carefully controlling these parameters, the process achieves high space-time yields while maintaining the simplicity of liquid-phase operation. The catalyst preparation parameters (reduction temperature, calcination conditions) are also optimized to ensure maximum catalytic activity.
2Ease of operation
If conventional catalysts are used for MEG amination, then the process can proceed in liquid phase, but unwanted by-products such as piperazine and higher ethanolamines are formed in significant amounts, reducing manufacturing precision
Solution Approach 1:
The composite catalyst with specific metal combinations (Cu-Ni-Zn or Cu-Ni-Al) and controlled ratios is designed to enhance selectivity for linear amination products. The Zn or Al component specifically suppresses cyclization reactions that lead to piperazine formation, while the porous support structure controls product distribution by limiting secondary reactions. This composite approach achieves high selectivity (>80%) for MEA and EDA while maintaining liquid-phase operation simplicity.
3Quantity of substance
If EO is used as raw material for MEA production, then MEA can be produced, but the process requires complex EO handling infrastructure and produces by-products requiring separate distillation, increasing device complexity
Solution Approach 1:
The patent extracts the amination step from the complex EO-based process by using MEG as a stable, easily handled alternative raw material. This eliminates the need for EO storage and handling infrastructure, as well as the downstream distillation columns required to separate MEA from diethanolamine and triethanolamine by-products. The MEG amination process directly produces the desired MEA and EDA with minimal by-products, simplifying the overall process architecture.
Solution Approach 2:
Instead of using EO as the starting material, the patent uses MEG as a copy or alternative precursor that leads to the same or better products (MEA and EDA) through a simpler pathway. MEG is a stable liquid that can be stored and handled easily, unlike the gaseous and highly reactive EO. This substitution maintains product output while eliminating the complex EO handling infrastructure and by-product separation requirements.
4Device complexity
If gas phase amination of MEG is employed, then the process can be simplified, but catalyst deactivation occurs more rapidly and selectivity for linear products decreases, worsening reliability
Solution Approach 1:
The patent optimizes the liquid-phase reaction parameters including temperature (150-350°C), pressure (1-30 bar), and reactant ratios to maintain catalyst stability and prevent deactivation. The liquid phase provides better heat and mass transfer, preventing local hot spots that cause catalyst degradation. The controlled pressure and temperature conditions ensure consistent catalyst performance over extended operation periods, achieving both process simplicity and high reliability.
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
The process achieves high selectivity for MEA and EDA, reduces the formation of unwanted by-products like piperazine and aminoethylethanolamine, and exhibits high catalyst activity, resulting in improved space-time yields and economic viability.
Implementation Method 1
a heterogeneous catalyst obtained by reducing a catalyst precursor
Implementation Method 2
using a heterogeneous catalyst obtained by reducing a catalyst precursor. The catalyst precursor is prepared by contacting a mixture of Sn, Cu, and Ni with a soluble Re compound, enhancing selectivity for linear amination products like MEA and EDA
Data Source
AI summary
The present invention relates to a process for preparing alkanolamines and ethyleneamines in the liquid phase, by reacting ethylene glycol and/or monoethanolamine with ammonia in the presence of an amination catalyst which is obtained by reducing a catalyst precursor, wherein the preparation of the catalyst precursor comprises a step a) in which a catalyst precursor comprising one or more catalytically active components of Sn, Cu and Ni, and a step b) in which the catalyst precursor prepared in step a) is contacted with a soluble Re compound.