Mo-Ru Sugar Hydrogenolysis for Propylene Glycol Selectivity
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Solution Overview
Problem
Existing methods for producing biobased glycols from sugars are inefficient, leading to high production costs and difficulty in separating propylene glycol from ethylene glycol and other higher polyols, which reduces overall productivity.
Innovation Solution
A one-step hydrogenolysis process using a bimetallic catalyst comprising molybdenum (Mo) and ruthenium (Ru) to enhance the selectivity of propylene glycol production while minimizing the formation of ethylene glycol and higher polyols, with optimized reaction conditions in a fixed-bed reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts (Ru, Rh, Ir, Pd) are used for sugar hydrogenolysis, then high activity is achieved, but selectivity for glycol production is poor and costs are high
Solution Approach 1:
The patent employs a composite catalyst system combining Group 8-10 metal (Ru, Rh, Ir, or Pd) with molybdenum sulfide (MoS2) or molybdenum oxide (MoO3). This composite structure leverages the high activity of conventional metals while MoS2/MoO3 provides selective functionality to direct reactions toward glycol products, resolving the selectivity issue without sacrificing productivity.
Solution Approach 2:
Molybdenum sulfide or molybdenum oxide acts as an intermediary component that modifies the catalytic behavior of the primary metal catalyst. This intermediary substance facilitates selective hydrogenolysis reactions, steering the reaction pathway toward glycol formation while maintaining the high activity of the parent metal catalyst.
2Productivity
If conventional catalysts are used for sugar hydrogenolysis, then high activity is achieved, but the cost is high
Solution Approach 1:
The patent modifies the catalytic system by introducing molybdenum-based compounds that change the chemical environment and electronic properties of the active sites. This parameter change allows the use of lower amounts of expensive Group 8-10 metals while maintaining high activity, thereby reducing overall catalyst cost.
3Manufacturing precision
If MoS2 or MoO3 is used as catalyst, then high selectivity for glycol is achieved, but activity is low
Solution Approach 1:
The patent merges MoS2/MoO3 (providing selectivity) with Group 8-10 metals (providing activity) into a synergistic composite catalyst system. The combination allows both selectivity and activity to be achieved simultaneously, as each component compensates for the other's weakness.
Solution Approach 2:
Different regions or components of the catalyst perform different functions: the Group 8-10 metal sites provide high activity for hydrogen activation and bond cleavage, while MoS2/MoO3 sites provide selectivity for glycol formation. This local differentiation of function resolves the activity-selectivity trade-off.
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 propylene glycol selectivity and productivity, reducing separation costs and improving overall efficiency by minimizing the formation of difficult-to-separate by-products.
Implementation Method 1
Sugar hydrogenolysis with molybdenum co-catalyst selective for producing glycols
Implementation Method 2
Sugar hydrogenolysis with molybdenum co-catalyst selective for producing glycols
Data Source
AI summary
A hydrogenolysis process is disclosed for directly converting a sugar feed comprised of a high fructose feedstock, a high sucrose feedstock, or a combination of these to a mixed lower polyols product including both propylene glycol and ethylene glycol. The process provides greater propylene glycol selectivity than ethylene glycol selectivity such that the propylene glycol is present to a greater extent than the ethylene glycol in the mixed lower polyols product. The sugar feed and a source of hydrogen are supplied to a reaction vessel and reacted in the presence of a hydrogenolysis catalyst comprising molybdenum (Mo) and ruthenium (Ru).