Acrylic Acid Production from Lactic Acid Oligomers
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Solution Overview
Problem
There is a need for an efficient process to manufacture acrylic acid from lactic acid oligomers or polymers in high yield, as traditional methods are either energy-demanding or result in lower purity and higher production costs due to the decreasing availability and increasing price of propylene, a conventional starting material.
Innovation Solution
A process involving a reaction mixture with a halide source, such as a bromide or chloride source, and optionally an acid with a pKa of at most 2.0, under conditions with less than 1 wt.% water, to convert lactic acid oligomers or polymers into acrylic acid and its ester with lactic acid, using catalysts like magnesium bromide or aluminium bromide to achieve high yields and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional propylene-based methods are used to manufacture acrylic acid, then the process is well-established and efficient, but the availability and price of propylene are decreasing due to environmental reasons and changes in gasoline production
Solution Approach 1:
The patent changes the starting material from propylene to lactic acid oligomers/polymers, fundamentally altering the chemical pathway. This parameter change allows production to continue despite propylene availability issues, as lactic acid can be obtained from renewable resources through fermentation
Solution Approach 2:
The patent uses inexpensive homogeneous catalysts such as magnesium bromide or aluminium bromide that can be easily handled and replaced. These catalysts operate effectively in the liquid phase and do not require complex recovery systems, making the process economically viable despite the shift from traditional propylene-based methods
2Quantity of substance
If multi-step energy-demanding processes like US2012/0078004 are used to convert lactide to acrylic acid, then acrylic acid can be produced from renewable resources, but the process requires multiple steps including pyrolysis which increases energy consumption
Solution Approach 1:
The patent employs a continuous one-pot reaction process that converts lactic acid oligomers or polymers directly to acrylic acid without intermediate isolation or pyrolysis steps. The reaction proceeds through continuous action of the halide source and acid catalyst in the liquid phase, eliminating energy-intensive heating and cooling cycles required by multi-step processes
Solution Approach 2:
The patent combines multiple reaction steps into a single integrated process. The halide source-mediated conversion and esterification reactions occur simultaneously in one reaction vessel under identical conditions, merging what would traditionally require separate pyrolysis and esterification units into a single efficient operation
3Ease of operation
If conventional catalysts are used in the conversion of lactic acid oligomers to acrylic acid, then the process may be simpler to operate, but the yield of acrylic acid is lower and by-products such as 2-bromopropionic acid and 3-bromopropionic acid are formed in higher amounts
Solution Approach 1:
The patent introduces a halide source as an intermediary agent that mediates the conversion of lactic acid oligomers to acrylic acid. This intermediary facilitates the reaction through a specific mechanism that avoids direct acid-catalyzed pathways which produce more by-products, thereby improving both yield and selectivity while maintaining operational simplicity
Solution Approach 2:
The patent employs a composite catalytic system combining a halide source with specific acids (such as sulfuric acid, phosphoric acid, or methanesulfonic acid). This composite approach creates synergistic effects where the halide source enhances the catalytic activity and selectivity, achieving high acrylic acid yields with minimal by-products while keeping the process easy to operate
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 allows for the efficient production of acrylic acid and its ester with lactic acid, achieving yields above 30% with reduced by-products, particularly 2-bromopropionic and 3-bromopropionic acids, and can be operated in the liquid phase with inexpensive homogeneous catalysts, making it economically viable and environmentally friendly.
Implementation Method 1
A process involving a reaction mixture with a halide source, such as a bromide or chloride source, and optionally an acid with a pKa of at most 2.0, under conditions with less than 1 wt.% water, to convert lactic acid oligomers or polymers into acrylic acid and its ester with lactic acid, using catalysts like magnesium bromide or aluminium bromide
Implementation Method 2
An advantage of using lactide as starting material is that the conversion into acrylic acid is a rearrangement reaction and does not require removal of water
Data Source
AI summary
Set forth is a process for preparing acrylic acid and/or the ester of acrylic acid and lactic acid from a lactic acid oligomer or polymer. As a result of the use of a bromide source and/or a chloride source in combination with a specific acid, a process that can be operated to obtain a high yield, and is relatively easy to perform, is realized.