Direct Lactic Acid Synthesis via Segmented Catalyst Mixture
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Solution Overview
Problem
Current methods for producing lactic acid are costly, environmentally impactful, and require multiple stages due to the need for alkaline solutions and high temperatures/pressures, often resulting in the production of lactic acid salts that require additional hydrolysis steps, generating solid residues and increasing process complexity.
Innovation Solution
A single-stage process for the selective oxidation of 1,2-propanediol using a mixture of heterogeneous catalysts, including a noble metal supported on metallic oxide and a basic catalyst, operates at low temperatures and pressures without the addition of bases or alkaline solutions, allowing direct production of lactic acid with selectivity between 50% and 97%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods using alkaline solutions and high temperatures/pressures are used, then lactic acid can be produced, but the process requires multiple stages, generates solid residues, and increases process complexity
Solution Approach 1:
The patent divides the catalytic system into two distinct functional components: a metallic oxide catalyst for oxidation and a basic catalyst for pH control. This segmentation allows each catalyst to perform its specific function optimally, enabling direct lactic acid production without forming salts that would require additional hydrolysis steps, thus reducing process complexity while maintaining productivity
Solution Approach 2:
The basic catalyst acts as an intermediary that mediates between the oxidation reaction and the final product formation. It controls the pH environment to prevent lactic acid from converting to its salt form, allowing direct recovery of lactic acid without requiring additional separation and hydrolysis stages
2Reliability
If alkaline solutions are added to control pH, then lactic acid salt is formed, but additional hydrolysis steps are required generating solid residues
Solution Approach 1:
The patent changes the pH control parameter from using soluble alkaline solutions to using a heterogeneous basic catalyst. This parameter change allows pH control to be achieved without introducing soluble ions that would form salts requiring hydrolysis, thereby preventing solid residue generation while maintaining reliable pH control
Solution Approach 2:
The invention extracts the pH control function from the traditional alkaline solution system and implements it through a solid basic catalyst. This extraction eliminates the need for subsequent acid hydrolysis steps that would generate solid salt residues, as the basic catalyst remains in solid form and can be easily separated
3Productivity
If high temperatures and pressures are used, then reaction rate increases, but energy cost and equipment requirements increase
Solution Approach 1:
The patent replaces the mechanical/thermal energy input (high temperature and pressure) with a chemical catalytic system. The metallic oxide and basic catalysts provide alternative reaction pathways with lower activation energies, enabling the reaction to proceed at moderate temperatures and pressures while maintaining high reaction rates, thus reducing energy costs and equipment requirements
4Manufacturing precision
If multiple separation and treatment steps are used, then product purity is achieved, but process cost and time increase
Solution Approach 1:
The patent combines the catalysis and pH control functions into a single reaction stage using a mixture of metallic oxide and basic catalysts. This merging eliminates the need for separate hydrolysis and purification stages required in conventional processes, achieving product purity in a single step and significantly reducing process time
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 process reduces costs, minimizes environmental impact, and eliminates the need for additional separation and treatment steps, achieving efficient and direct production of lactic acid with high selectivity and yield.
Implementation Method 1
selective oxidation of 1,2-propanediol using a mixture of heterogeneous catalysts, including a noble metal supported on metallic oxide and a basic catalyst
Implementation Method 2
selective oxidation of the primary hydroxyl of the 1,2-propanediol to lactic acid
Data Source
AI summary
This invention concerns a process for obtaining lactic acid in a single stage by direct oxidation in an aqueous medium of 1,2-propanediol in the presence of a mixture of heterogeneous catalysts, in conditions of low temperature and low pressure. The reaction takes place in the presence of oxygen and a mixture of heterogeneous catalysts, consisting of a first catalyst of noble metal supported in metallic oxide, and a second basic solid catalyst. The mixture of catalysts is easily recovered by filtration at the end of the process, to be reused. The lactic acid is obtained directly, with selectivity between 50% and 97%.