Silver Catalyst on Basic Alumina for Glycerol Oxidation
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Solution Overview
Problem
Current methods for synthesizing glycolic acid from glycerol suffer from low selectivity and high production costs due to the use of fossil-based resources and excessive base usage, leading to salt production and environmental impact.
Innovation Solution
A process using a supported silver catalyst on a CeO2, basic Al2O3, or amphoteric resin support, with a controlled molar ratio of hydroxyl ions to glycerol, and minimal noble metal content, to catalytically oxidize glycerol to glycolic acid, reducing base consumption and salt production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If base is used in large excess (base/glycerol ratio of approximately 4) to promote glycolic acid synthesis, then conversion rate is improved, but salt production increases significantly leading to higher production costs and environmental impact
Solution Approach 1:
The invention changes the key parameter of base-to-glycerol molar ratio from the conventional excess ratio (approximately 4:1) to a stoichiometric or near-stoichiometric ratio (0.5 to 1.2:1). This parameter change maintains sufficient conversion rate while dramatically reducing the amount of base consumed and consequently the salt produced during acidification, directly resolving the contradiction between productivity and substance loss.
Solution Approach 2:
The invention replaces the conventional practice of using large amounts of base (which leads to waste) with a precisely controlled, minimal amount of base. The supported silver catalyst enables this reduction by providing an alternative reaction pathway that is less dependent on excess base, thereby reducing waste generation without sacrificing productivity.
2Power
If commonly used catalysts (gold, platinum, or palladium-based) are used for glycerol oxidation, then catalytic activity is improved, but selectivity for glycolic acid is poor with glyceric acid being the major product
Solution Approach 1:
The invention applies local quality by using silver specifically supported on basic alumina, creating a catalyst with localized basic sites on the support surface. This local basic environment selectively promotes the formation of glycolic acid over glyceric acid, achieving high selectivity while maintaining catalytic activity, thus resolving the contradiction between power and manufacturing precision.
Solution Approach 2:
The invention uses a composite catalyst system consisting of silver metal particles supported on basic alumina. This composite structure combines the catalytic activity of silver with the basic properties of alumina, creating a synergistic effect that simultaneously achieves high catalytic activity and high selectivity for glycolic acid, overcoming the limitations of conventional single-metal catalysts.
3Productivity
If fossil-derived compounds are used as starting materials for glycolic acid synthesis, then production efficiency is improved, but environmental impact and sustainability are worsened
Solution Approach 1:
The invention changes the nature of the starting material from fossil-derived compounds to bio-based glycerol, a parameter change that transforms the sustainability profile of the process. This substitution maintains production efficiency through effective catalysis while eliminating the environmental harm associated with fossil resource depletion, directly resolving the contradiction between productivity and harmful factors.
Solution Approach 2:
The invention replaces non-renewable fossil resources with renewable bio-based glycerol, effectively substituting a depleting resource with a renewable one. This substitution, enabled by the efficient supported silver catalyst, maintains productivity while eliminating the environmental harm of fossil resource consumption.
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
Achieves high selectivity and conversion rates for glycolic acid production, with reduced salt production and environmental impact, utilizing biosourced glycerol and minimizing fossil resource dependence.
Implementation Method 1
a contact in a reaction medium of glycerol and an oxidizing agent in the presence of a silver-based catalyst on a support
Implementation Method 2
the catalytic oxidation of glycerol to glycolic acid
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method for synthesising glycolic acid or one of the salts thereof, including the following step: placing glycerol and an oxidising agent in contact with one another in a reaction medium in the presence of a silver-based catalyst on a substrate, said substrate including a material selected from the group consisting of CeO2, basic Αl2Ο3 optionally doped with a calcium or cerium oxide, an amphoteric resin, ZrO2, and a mixture of said materials. The invention also relates to the use of a silver-based catalyst on a substrate that can be used in said method.