Acetic Acid and Dimethyl Ether Co-Production Process
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Solution Overview
Problem
Existing processes for co-producing acetic acid and dimethyl ether from methanol and methyl acetate struggle with achieving high acetic acid purity due to the presence of formic acid, which is difficult to separate using conventional distillation methods due to its close boiling point with acetic acid.
Innovation Solution
A process involving the purification of a mixture of dimethyl ether, methanol, water, and methyl formate through distillation to generate streams depleted or enriched in methyl formate, followed by a dehydration-hydrolysis reaction using a solid acid catalyst to produce acetic acid and dimethyl ether, effectively reducing formic acid content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fractional distillation is used to separate formic acid from acetic acid, then the separation process can be performed with simple equipment, but the acetic acid purity cannot be sufficiently improved due to the closeness of boiling points
Solution Approach 1:
The patent applies preliminary action by removing methyl formate from the feed mixture before the dehydration-hydrolysis reaction. This prevents formic acid from being generated in the first place, thereby avoiding the need for complex post-reaction separation processes and directly achieving high acetic acid purity.
Solution Approach 2:
The patent converts the harmful effect of methyl formate (which generates difficult-to-separate formic acid) into a beneficial outcome by selectively removing it beforehand. This transforms a potential problem into an opportunity to simplify the overall process and improve product purity.
2Manufacturing precision
If complex extractive distillation methods are used to separate formic acid from acetic acid, then acetic acid purity can be improved, but the process complexity and operational difficulty increase significantly
Solution Approach 1:
By removing methyl formate from the feed before the reaction, the patent eliminates the source of formic acid contamination. This preliminary action avoids the need for complex extractive distillation operations, thereby maintaining high acetic acid purity while preserving ease of operation.
3Adaptability or versatility
If methyl formate is present in the methanol or methyl acetate feedstocks, then the feed composition requirements are easier to meet, but formic acid is generated which complicates the separation process
Solution Approach 1:
The patent applies the extraction principle by specifically removing methyl formate from the feed mixture through distillation before the dehydration-hydrolysis reaction. This extraction step eliminates the source of formic acid generation, allowing flexible feedstock composition while avoiding complex separation requirements downstream.
Solution Approach 2:
By performing methyl formate removal as a preliminary step before the main reaction, the patent enables the use of flexible feedstocks containing methyl formate while preventing the formation of difficult-to-separate formic acid in the final product.
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 acetic acid with a formic acid content of 500 ppm or less, simplifying the separation and reducing the need for complex extractive distillation methods.
Implementation Method 1
distilling the feed mixture of dimethyl ether, methanol, water, formic acid and methyl formate to generate a heads stream depleted in methyl formate as compared to the feed mixture
Implementation Method 2
dehydrating methanol and hydrolysing methyl acetate therein in the presence of at least one solid acid catalyst to produce a crude reaction product comprising acetic acid and dimethyl ether
Implementation Method 3
dehydrating methanol
Implementation Method 4
hydrolysing methyl acetate
Data Source
AI summary
Process for the co-production of acetic acid and dimethyl ether with reduced formic acid content by distilling a mixture containing dimethyl ether, methanol and methyl formate, separating methyl formate from the mixture to recover dimethyl ether and methanol, and catalytically reacting the methanol and methyl acetate to produce a reaction product of acetic acid an dimethyl ether.