Ni-Re-Cd Catalyst Selectivity in Hydrogenolysis
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Solution Overview
Problem
Current methods for producing propylene glycol from sugar alcohols through hydrogenolysis result in the formation of unwanted by-products like ethylene glycol and diols, which are difficult to separate and increase production costs.
Innovation Solution
A catalyst comprising nickel (Ni), rhenium (Re), and cadmium (Cd) is used in the hydrogenolysis reaction to enhance selectivity towards propylene glycol production, reducing the formation of other polyols and improving separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrogenolysis catalysts are used to produce propylene glycol from sugar alcohols, then propylene glycol is produced, but unwanted by-products such as ethylene glycol and diols are formed which are difficult to separate
Solution Approach 1:
The patent modifies the catalyst composition parameters by incorporating specific ratios of Ni (3-7 wt%), Re (0.2-1.8 wt%), and Cd (0.2-3.0 wt%) on carbon support, along with controlling reaction conditions such as temperature (150-300°C), pressure (500-2000 psi), and LHSV (0.5-10.0 hr⁻¹) to optimize selectivity toward propylene glycol while minimizing by-product formation
Solution Approach 2:
The invention uses a composite catalyst system combining multiple metal components (Ni, Re, Cd) on a carbon support material. This composite structure synergistically enhances catalytic activity for propylene glycol production while suppressing side reactions that produce difficult-to-separate by-products like ethylene glycol and diols
2Manufacturing precision
If processes are developed to separate propylene glycol from diols and ethylene glycol, then pure propylene glycol can be obtained, but the process becomes time consuming and expensive
Solution Approach 1:
The catalyst is designed to perform preliminary selective action during the hydrogenolysis reaction itself, preferentially forming propylene glycol while minimizing by-product formation from the start. This preliminary selectivity reduces the burden on subsequent separation processes by limiting the amount of difficult-to-separate by-products that need to be removed
Solution Approach 2:
By optimizing reaction parameters including temperature (150-300°C), pressure (500-2000 psi), and liquid hourly space velocity (0.5-10.0 hr⁻¹), the process achieves high propylene glycol selectivity that simplifies downstream separation requirements, reducing both time and cost while maintaining high purity
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 catalyst achieves higher productivity and cost-effective recovery of pure propylene glycol by minimizing the production of unwanted by-products, thereby optimizing the propylene glycol production process.
Implementation Method 1
a catalyst comprising Ni, Re, and Cd is used in the hydrogenolysis reaction to enhance selectivity towards propylene glycol production
Implementation Method 2
The hydrogenolysis reaction is effectuated by catalysts such as those described in US Patent Application Publication 2009/0088317
Data Source
AI summary
A hydrogenation catalyst comprising nickel, rhenium, and cadmium is disclosed. Process of using hydrogenation catalyst for producing propylene glycol from polyol feedstock are also disclosed. The present invention relates generally to catalysts and more particularly, to catalysts having an enhanced ability to produce propylene glycol from sugar alcohols while reducing the production of by-products.