Silver Tungstate Catalyst System for Low-Temperature Glycol Production
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Solution Overview
Problem
Current methods for converting saccharides to glycols, such as monoethylene glycol and monopropylene glycol, require high reactor temperatures, leading to energy inefficiencies and by-product formation, and there is a need to operate at lower temperatures without compromising glycol yields.
Innovation Solution
A catalyst system comprising silver tungstate and one or more transition metal species for hydrogenation, with a weight ratio greater than 4:1, allows for the conversion of saccharides to glycols at reactor temperatures between 145 and 190 °C, achieving high yields while reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high reactor temperatures are used for converting saccharides to glycols, then the conversion rate and productivity are improved, but energy consumption increases and by-product formation increases
Solution Approach 1:
The invention changes the chemical parameters of the reaction system by introducing a dual-catalyst system comprising tungsten carbide and nickel. This catalyst combination enables the retro-aldol reaction and hydrogenation to proceed efficiently at lower temperatures (145-190°C), thereby reducing energy consumption while maintaining high conversion rates and minimizing by-product formation.
Solution Approach 2:
The invention employs a composite catalyst system combining tungsten carbide (for retro-aldol reaction) and nickel (for hydrogenation). This composite material approach allows the two catalytic functions to work synergistically, enabling low-temperature operation with high productivity by matching each catalyst's optimal temperature range.
2Productivity
If high reactor temperatures are used for converting saccharides to glycols, then the conversion rate is improved, but by-product formation increases
Solution Approach 1:
The invention optimizes the temperature parameter to the range of 145-190°C, which is sufficiently high to maintain good conversion rates but low enough to suppress unwanted side reactions and by-product formation. The dual-catalyst system ensures that this moderate temperature is effective for both retro-aldol and hydrogenation steps.
Solution Approach 2:
The invention applies different catalytic functions at different stages of the reaction pathway. Tungsten carbide catalyzes the retro-aldol reaction to break down saccharides into C2 and C3 fragments, while nickel subsequently catalyzes the hydrogenation of these fragments to form glycols. This localized catalytic approach ensures high selectivity and minimizes by-product formation.
3Reliability
If high hydrogen pressure is used to maintain high glycol yields at lower temperatures, then product yields are maintained, but equipment complexity and corrosion increase
Solution Approach 1:
The invention changes the pressure parameter to a moderate range of 3-10 MPa, which is sufficient to maintain high hydrogenation activity at lower temperatures without requiring excessively high pressures. The nickel catalyst's high activity allows effective hydrogenation at these moderate pressures, reducing equipment complexity and corrosion risks.
Solution Approach 2:
The invention optimizes the temperature parameter to the range of 145-190°C, which is sufficiently high to maintain good conversion rates but low enough to suppress unwanted side reactions and by-product formation. The dual-catalyst system ensures that this moderate temperature is effective for both retro-aldol and hydrogenation steps.
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 approach enables the production of glycols at lower temperatures, increasing energy efficiency, reducing by-product formation, and maintaining high product yields, while also allowing for lower hydrogen pressure and reduced metallurgy corrosion.
Implementation Method 1
catalyst system comprising: silver tungstate; and one or more catalytic species suitable for hydrogenation
Implementation Method 2
a first catalytic species to perform the hydrogenolysis reaction, which is postulated to have a retro-aldol mechanism
Implementation Method 3
one or more catalytic species suitable for hydrogenation, wherein the one or more catalytic species suitable for hydrogenation are selected from one or more transition metals from Groups 8, 9 or 10 of the Periodic Table
Implementation Method 4
a second catalytic species for hydrogenation
Data Source
Figure 1
AI summary
The invention provides a catalyst system comprising: a) one or more silver tungstate-containing species; and b) one or more catalytic species suitable for hydrogenation, wherein the weight ratio of said one or more silver tungstate-containing species to the one or more catalytic species suitable for hydrogenation is greater than 2.5:1, on the basis of the total weight of the catalyst system; and a process for the preparation of monoethylene glycol from starting material comprising one or more saccharides, by contacting said starting material with hydrogen in a reactor at a reactor temperature in the range of from 145 to 190 °C in the presence of a solvent and said catalyst system.