Ethylene Glycol Production Catalyst System
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Solution Overview
Problem
Existing processes for producing ethylene glycol from carbohydrate sources face challenges such as reduced yields over time due to catalyst degradation, formation of by-products like butylene glycol, and difficulties in separating ethylene glycol from butylene glycol due to their azeotrope formation, which complicates distillation and reduces overall efficiency.
Innovation Solution
A process using a catalyst system comprising tungsten compounds and ruthenium as hydrogenolysis metals, combined with transition or post-transition metals like tin, supported on carriers like activated carbon, which enhances ethylene glycol yield and allows for selective removal of butylene glycol through azeotropic distillation using suitable entraining agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst system containing nickel and tungsten is used, then ethylene glycol can be produced from carbohydrate sources, but the catalyst components leach into the solution causing gradual deterioration of catalyst performance
Solution Approach 1:
The patent changes the oxidation state parameter of tungsten from metallic state (0) to higher oxidation states (+2, +3, +4, +5, or +6) in the form of tungsten compounds. This parameter change prevents leaching of tungsten into the solution, thereby maintaining catalyst performance stability over time while continuing to produce ethylene glycol effectively.
Solution Approach 2:
The patent employs a composite catalyst system combining tungsten compounds (in higher oxidation states) with hydrogenation metals (Groups 8-10). This composite structure synergistically improves both the stability and activity of the catalyst, preventing leaching while maintaining high ethylene glycol production efficiency.
2Productivity
If the reaction is continued for a prolonged period, then more carbohydrate can be converted, but the ethylene glycol yield reduces due to catalyst degradation
Solution Approach 1:
By changing the oxidation state of tungsten to +2 or higher, the catalyst maintains its structural integrity and catalytic activity over prolonged reaction periods. This parameter change enables extended reaction times with consistent ethylene glycol yield, allowing greater carbohydrate conversion without the yield reduction caused by catalyst degradation.
3Productivity
If butylene glycol is produced along with ethylene glycol, then the product mixture contains desired ethylene glycol, but separation becomes difficult due to azeotrope formation
Solution Approach 1:
The patent introduces a promoter metal component that specifically modifies the catalytic properties to favor ethylene glycol formation over butylene glycol. This local quality enhancement at the catalyst active sites selectively promotes the desired reaction pathway, reducing by-product formation and simplifying the separation process.
Solution Approach 2:
The addition of promoter metals changes the catalytic parameters to improve selectivity toward ethylene glycol. This parameter modification reduces the formation of butylene glycol by-products, thereby decreasing the complexity of separation operations required to obtain pure ethylene glycol.
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 increases ethylene glycol yield while minimizing butylene glycol production, facilitating easier separation and purification, thereby improving the overall efficiency and effectiveness of ethylene glycol production from carbohydrate sources.
Implementation Method 1
a catalyst system comprises a tungsten compound and ruthenium as hydrogenolysis metal
Implementation Method 2
selective removal of butylene glycol through azeotropic distillation using suitable entraining agents
Data Source
AI summary
Ethylene glycol is prepared from a carbohydrate source in a process, wherein hydrogen, the carbohydrate source, a liquid diluent and a catalyst system are introduced as reactants into a reaction zone; wherein the catalyst system comprises a tungsten compound and ruthenium as hydrogenolysis metal and further at least one promoter metal, selected from transition and post-transition metals; wherein the carbohydrate source is reacted with hydrogen in the presence of the catalyst system to yield a product mixture comprising ethylene glycol and butylene glycol. Butylene glycol may selectively be removed from the product mixture by azeotropic distillation using an entraining agent.