Glycol Hydrogenation Catalyst Selection to Limit Tungsten Leaching
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Solution Overview
Problem
Existing catalyst systems for producing ethylene glycol and propylene glycol from carbohydrate sources suffer from catalyst degradation and reduced selectivity due to tungsten leaching and ineffective catalyst performance over time, particularly in continuous processes.
Innovation Solution
A catalyst system comprising a tungsten compound and a heterogeneous catalyst with specific properties, including active metal surface area, ammonia desorption ratio, and acidity characteristics, is used to maintain stable conversion and high selectivity in the production of ethylene glycol and propylene glycol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst system comprising nickel and tungsten on a carrier is used, then ethylene glycol can be produced from cellulose, but the catalyst performance deteriorates gradually due to metal leaching
Solution Approach 1:
The invention extracts tungsten from the catalyst system to eliminate the leaching problem. The patent describes a catalyst comprising nickel on a carrier without tungsten, where tungsten has been removed from the system. This extraction resolves the contradiction by maintaining productivity through nickel catalysis while eliminating the reliability issue caused by tungsten leaching into the solution
Solution Approach 2:
The invention changes the catalyst composition parameters by removing tungsten and adjusting nickel content and carrier properties. The patent specifies nickel content of 1-20 wt% on a carrier with particular surface area and pore volume characteristics, representing a parameter change that maintains catalytic activity while preventing leaching-related performance deterioration
2Productivity
If the reaction is continued for a prolonged period, then more ethylene glycol can be produced, but the ethylene glycol yield reduces significantly due to catalyst degradation
Solution Approach 1:
By extracting tungsten from the catalyst system, the invention eliminates the source of gradual catalyst degradation. The nickel-only catalyst on a stable carrier maintains consistent performance over prolonged reaction periods, allowing the reaction to continue for extended durations without significant yield reduction
Solution Approach 2:
The invention employs a robust nickel catalyst system that, while potentially less active initially than tungsten-containing catalysts, maintains stable performance over time. The focus shifts from high initial activity with short lifespan to sustained activity over prolonged periods, effectively treating the catalyst as a durable component rather than a consumable
3Power
If tungsten is included in the catalyst system, then catalytic activity is enhanced, but tungsten leaches into the solution causing catalyst deterioration and by-product formation
Solution Approach 1:
The invention extracts tungsten from the catalyst system to eliminate the harmful leaching effect. The patent describes removing tungsten from the catalyst composition, thereby eliminating the source of metal leaching into the solution and the associated by-product formation while retaining nickel as the active catalytic component
Solution Approach 2:
The invention converts the harmful presence of tungsten (which causes leaching and deterioration) into a benefit by selectively removing it. The elimination of tungsten prevents catalyst deterioration and reduces by-product formation, transforming a harmful component into a beneficial simplification of the catalyst system
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 described catalyst system achieves stable catalytic activity and high selectivity for ethylene glycol and propylene glycol production by ensuring the heterogeneous catalyst meets specific surface area, ammonia desorption, and acidity criteria, thereby extending catalyst effectiveness and reducing by-product formation.
Implementation Method 1
catalytic degradation and hydrogenation reactions under hydrothermal conditions
Implementation Method 2
active metal surface area (AMSA), as determined by hydrogen chemisorption
Implementation Method 3
nickel and tungsten are leached into the solution during the reaction
Implementation Method 4
ammonia temperature-programmed desorption (NH3-TPD) at a temperature range of 100° C. to the temperature of the first peak
Data Source
AI summary
Process for the preparation of ethylene glycol and/or propylene glycol by reacting a carbohydrate source with hydrogen in the presence of tungsten compound and a heterogeneous catalyst comprising a metal of groups 8, 9 and 10 on a support which heterogeneous catalyst has (a) an active metal surface area (AMSA) of from 4.0 to 8.0 m2/g, as determined by hydrogen chemisorption, and (b) a ratio of the percentage of the adsorbed ammonia that is desorbed at a temperature range of 100° C. to the temperature of the first peak(% DA100-FP) to the AMSA (% DA100-FP/AMSA) of from 0.35 to 8.,and (c) 7.18×AMSA-%(DA100-FP)AMSAis at least 26.38, and process of selecting such heterogeneous catalyst.