Transesterification of Lactate Esters to MAP
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current synthetic routes from lactic acid to methyl 2-acetoxypropionate (MAP) suffer from low conversions and the production of unwanted by-products, along with corrosion issues due to water presence and difficulty in separating impurities, leading to inefficient and costly processes.
Innovation Solution
A process involving heating a mixture of an alkyl or aryl ester of an α-hydroxyalkanoic acid with an alkyl or aryl acetate under superatmospheric pressure and in the presence of a transesterification catalyst to produce 2-acetoxyalkanoic acid esters, using esters of lactic acid and acetate in anhydrous form to minimize corrosion and by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lactic acid is reacted with methyl acetate to form MAP, then the reaction can proceed with readily available starting materials, but conversions to MAP are disappointingly low and large amounts of unwanted by-products are produced
Solution Approach 1:
The patent changes the physical state parameter from using lactic acid (aqueous) to using lactate esters (organic soluble form), and changes the reaction condition parameter by using superatmospheric pressure and elevated temperature (150-250°C) to achieve high conversions while maintaining selectivity
Solution Approach 2:
The patent introduces a transesterification catalyst as an intermediary substance to facilitate the reaction between lactate ester and acetate ester, enabling high conversion to MAP without the side reactions that occur with lactic acid
2Device complexity
If lactic acid is used as starting material, then the process can be simple, but water is always present which hydrolyzes ester compounds back to starting materials and causes corrosion
Solution Approach 1:
The patent extracts water from the system by using lactate esters instead of lactic acid as the starting material. This eliminates the water that causes hydrolysis and corrosion, while the ester form provides the same chemical functionality needed for MAP production
Solution Approach 2:
The patent creates an inert environment by conducting the reaction under superatmospheric pressure with organic solvents/starting materials that do not contain water, preventing hydrolysis reactions and corrosion of equipment
3Object-affected harmful factors
If water is removed from lactic acid to prevent hydrolysis, then corrosion is reduced, but oligomerization of lactic acid occurs leading to diminished yields
Solution Approach 1:
Instead of removing water from lactic acid (which causes oligomerization), the patent inverts the approach by using lactate esters as the starting material. This provides the same water-free environment needed to prevent hydrolysis, while the ester functional group prevents oligomerization side reactions
4Ease of manufacture
If conventional routes are used to convert lactic acid to MAP, then the process can be straightforward, but separations are difficult and expensive due to azeotrope formation
Solution Approach 1:
The patent changes the chemical form parameter from lactic acid to lactate esters, which fundamentally alters the separation behavior. The ester form eliminates azeotrope formation with water, making separations straightforward through standard distillation or extraction methods
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 high yields and selectivity of 2-acetoxyalkanoic acid esters with reduced corrosion and easy recovery of by-products, enabling efficient production of MAP and other esters with improved yield and selectivity compared to prior art.
Implementation Method 1
heating a mixture of an alkyl or aryl ester of an α-hydroxyalkanoic acid and at least one mole of an alkyl or aryl acetate per mole of the α-hydroxyalkanoic acid ester to a temperature of at least 150° C. under superatmospheric pressure in the presence of a transesterification catalyst
Implementation Method 2
heating a mixture of an alkyl or aryl ester of an α-hydroxyalkanoic acid and at least one mole of an alkyl or aryl acetate per mole of the α-hydroxyalkanoic acid ester to a temperature of at least 150° C.
Implementation Method 3
heating a mixture of an alkyl or aryl ester of an α-hydroxyalkanoic acid and at least one mole of an alkyl or aryl acetate per mole of the α-hydroxyalkanoic acid ester to a temperature of at least 150° C. under superatmospheric pressure
Data Source
AI summary
2-Acetoxyalkanoic acid esters are made in a reaction of an α-hydroxyalkanoic acid ester and an acetate ester in the presence of a transesterification catalyst. Unlike previous methods for making 2-acetoxyalkanoic acid esters, this process proceeds in high yield and high selectivity to the desired product.