Formate Ester Hydrolysis for Lower-Energy Formic Acid Separation
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Solution Overview
Problem
Conventional methods for producing formic acid, such as carbonylation of methanol to methyl formate followed by hydrolysis, are energy and capital intensive due to low conversion rates and the need for complex separation processes, particularly in separating formic acid from water, leading to high energy consumption and production costs.
Innovation Solution
A process involving the hydrolysis of formate esters of C3 to C4 alcohols, followed by distillation and alcohol recovery, to produce formic acid with high purity and reduce energy consumption, utilizing a hydrolysis zone, distillation zone, and alcohol recovery zone to enhance conversion and separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation is used to separate formic acid from water, then formic acid can be recovered, but energy consumption increases significantly due to the maximum-boiling azeotrope formation
Solution Approach 1:
The patent changes the physical parameters of the system by operating the distillation column at reduced pressure (vacuum conditions). This pressure change modifies the azeotrope composition and boiling points, allowing formic acid to be separated from water with lower energy input. The vacuum operation enables the formation of a heterogeneous azeotrope that can be more easily broken and separated.
Solution Approach 2:
The patent exploits phase transition behavior by utilizing the heterogeneous azeotrope formation between formic acid and water under vacuum conditions. The azeotrope forms a separate liquid phase that can be mechanically separated from the formic acid-rich phase, enabling energy-efficient separation without requiring excessive distillation energy.
2Productivity
If carbonylation of methanol to methyl formate is performed, then formic acid can be produced through hydrolysis, but conversion rates remain low requiring complex separation processes
Solution Approach 1:
The patent changes the chemical parameters by using formate esters of C3-C4 alcohols instead of methyl formate. These esters exhibit different physical properties including higher volatility and different azeotrope formation behavior with water, which simplifies the separation process and improves overall productivity.
Solution Approach 2:
Instead of following the conventional route of methanol carbonylation to methyl formate, the patent inverts the approach by using formate esters of higher alcohols (C3-C4) as intermediates. This reverse strategy exploits the favorable volatility differences and azeotrope behavior of these esters to achieve simpler separation and higher effective conversion.
3Manufacturing precision
If hydrolysis of formate esters is performed to produce formic acid, then conversion can be improved, but separation from alcohol and water becomes challenging
Solution Approach 1:
The patent changes the physical parameters by selecting formate esters of C3-C4 alcohols which have specific volatility characteristics. These esters form heterogeneous azeotropes with water that have different compositions from the parent alcohol-water azeotropes, enabling sequential separation and reducing process complexity.
Solution Approach 2:
The patent segments the separation process into distinct stages: first separating the formate ester from the hydrolysis mixture, then hydrolyzing to produce formic acid, and finally separating formic acid from water using the heterogeneous azeotrope behavior. This segmentation allows each separation challenge to be addressed independently with optimized conditions.
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
The process achieves formic acid production with greater than 75 wt.% purity and reduces energy consumption by optimizing hydrolysis and distillation steps, thereby lowering production costs and improving overall efficiency.
Implementation Method 1
hydrolyzing the formate ester of the alcohol
Implementation Method 2
feeding the hydrolysis effluent to a distillation zone and removing a formic acid product
Data Source
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AI summary
Disclosed is a process for recovering formic acid from a formate ester of a C3 to C4 alcohol. Disclosed is also a process for producing formic acid by carbonylating a C3 to C4 alcohol, hydrolyzing the formate ester of the alcohol, and recovering a formic acid product. The alcohol may be dried and returned to the reactor. The process enables a more energy efficient production of formic acid than the carbonylation of methanol to produce methyl formate.