Lactic Acid Dehydration Molten Salt Catalyst
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Solution Overview
Problem
Current methods for producing acrylic acid from renewable resources, such as lactic acid, in the liquid phase suffer from low yield and selectivity, and there is a need for more efficient dehydration processes that reduce energy consumption and CO2 emissions.
Innovation Solution
Contacting a feed stream containing lactic acid or its derivatives with a molten salt catalyst comprising an ionic liquid and an acid, specifically tetrabutylphosphonium bromide and pyrophosphoric acid, at controlled temperatures and pressures to achieve higher yields of acrylic acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If gas phase dehydration of lactic acid is used, then dehydration can proceed, but operating temperature and energy consumption are high
Solution Approach 1:
The patent changes the phase parameter from gas phase to liquid phase dehydration, and modifies temperature parameters to operate at 100-200°C instead of higher gas phase temperatures, thereby reducing energy consumption while maintaining dehydration effectiveness
Solution Approach 2:
The patent utilizes liquid phase dehydration instead of gas phase, leveraging phase transition benefits to lower operating temperature and energy requirements while achieving comparable or superior dehydration performance
2Productivity
If conventional liquid phase dehydration with metal salt catalysts is used, then liquid phase advantages are achieved, but acrylic acid yield is low
Solution Approach 1:
The patent employs composite catalyst systems combining metal salts (e.g., ZnCl2, AlCl3) with organic acids (e.g., HCl, H2SO4) or molecular sieves, creating synergistic effects that significantly enhance acrylic acid yield to 30-70% while maintaining process consistency and reliability
Solution Approach 2:
The patent introduces intermediate compounds such as 2-acetoxypropionic acid or 2-halo-propionic acid as reaction intermediates, which serve as better leaving groups and enable higher yield conversion to acrylic acid through controlled dehydration mechanisms
3Object-generated harmful factors
If lactic acid is used as feedstock from fossil resources, then acrylic acid can be produced, but greenhouse emissions are high
Solution Approach 1:
The patent changes the carbon source parameter from fossil-derived propylene to renewable lactic acid feedstock, and optimizes reaction parameters (temperature 100-200°C, catalyst composition, residence time) to maintain high production efficiency while achieving zero or low greenhouse gas emissions
Solution Approach 2:
The patent converts the traditionally harmful fossil fuel dependency and associated emissions into a beneficial renewable resource-based process, where lactic acid fermentation products are dehydrated to acrylic acid, transforming an environmental problem into a sustainable solution
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 method achieves acrylic acid yields of at least 30 mol% with improved selectivity and reduced energy use and CO2 emissions, making it a more efficient alternative to traditional gas phase dehydration processes.
Implementation Method 1
contacting a feed stream containing lactic acid, lactic acid derivatives, or mixtures thereof with a molten salt catalyst in liquid phase
Data Source
AI summary
Methods for making acrylic acid, acrylic acid derivatives, or mixtures thereof by contacting a feed stream containing lactic acid, lactic acid derivatives, or mixtures thereof with a molten salt catalyst comprising an ionic liquid (IL) and an acid in liquid phase are provided.