Methyl Acetate Hydrogenation Selectivity via Catalyst and Recycle
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Solution Overview
Problem
Current processes for producing ethanol from methyl acetate and acetic acid are inefficient, requiring increased energy, producing unwanted by-products, and lacking in selectivity towards ethanol and methanol.
Innovation Solution
A process involving the hydrogenation of methyl acetate over a copper-zinc oxide catalyst, using a hydrogenation feed composition with methyl acetate, water, and carbon oxides, operated at elevated temperatures and pressures, with recycling of gaseous streams to enhance selectivity and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional processes are used for producing ethanol from methyl acetate and acetic acid, then ethanol production is achieved, but energy consumption increases and selectivity towards ethanol and methanol decreases
Solution Approach 1:
The patent applies parameter changes by operating the hydrogenation reaction at specific temperature ranges (200-280°C) and pressure conditions (50-100 bar) to optimize both energy efficiency and selectivity. The copper-zinc oxide catalyst is maintained at specific operational parameters to achieve high ethanol and methanol selectivity while reducing energy consumption compared to conventional processes
Solution Approach 2:
The patent uses a composite copper-zinc oxide catalyst system where copper provides hydrogenation activity and zinc oxide provides structural stability and selectivity enhancement. This composite catalyst material achieves superior performance in terms of both energy efficiency and product selectivity compared to single-metal catalysts used in conventional processes
2Productivity
If conventional hydrogenation processes are used, then methyl acetate conversion is achieved, but by-products such as ethyl acetate are formed
Solution Approach 1:
The patent introduces carbon oxides (CO and/or CO2) as intermediary substances that modify the reaction pathway during hydrogenation. These carbon oxides act as mediators that suppress unwanted side reactions leading to ethyl acetate formation, while maintaining high methyl acetate conversion rates to ethanol and methanol
Solution Approach 2:
The patent optimizes the hydrogen-to-methyl acetate molar ratio and controls the presence of carbon oxides in the reaction mixture to specific levels. By adjusting these parameters, the process achieves high conversion rates while minimizing by-product formation through selective reaction pathway control
3Device complexity
If simplified processes are used for ethanol production, then process complexity is reduced, but productivity and selectivity decrease
Solution Approach 1:
The patent combines the hydrogenation reaction and catalyst activation steps into a single integrated process. The copper-zinc oxide catalyst is activated in situ within the hydrogenation reactor, eliminating the need for separate activation equipment and procedures. This merging maintains high productivity and selectivity while reducing overall process complexity
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 improves the selectivity towards ethanol and methanol, reduces energy consumption, and minimizes the formation of by-products, such as ethyl acetate, while maintaining high conversion rates of methyl acetate.
Implementation Method 1
hydrogenating the methyl acetate to produce a hydrogenation product stream comprising ethanol, methanol, unreacted methyl acetate, water, unreacted hydrogen, carbon monoxide, carbon dioxide, and ethyl acetate, wherein said hydrogenation unit is operated in the vapour phase at elevated temperature
Implementation Method 2
said hydrogenation unit is operated in the vapour phase at elevated temperature, preferably at a temperature in the range of from 180 to 270° C., and elevated pressure, preferably in the range of from 20 to 100 bara
Implementation Method 3
the hydrogenation product stream is separated into a first liquid product stream comprising the majority of the ethanol, methanol, unreacted methyl acetate, water, and ethyl acetate, and a first gaseous product stream comprising the majority of the unreacted hydrogen, carbon monoxide, and carbon dioxide
Data Source
AI summary
Hydrogenation of methyl acetate to methanol and ethanol by feeding a hydrogenation feed of methyl acetate, water, hydrogen and a carbon oxide into a hydrogenation unit containing a copper-zinc oxide hydrogenation catalyst to produce a hydrogenation product stream of ethanol, methanol, unreacted methyl acetate, water, unreacted hydrogen, carbon monoxide, carbon dioxide, and ethyl acetate. The hydrogenation unit is operated in the vapor phase at elevated temperature and pressure. The total molar ratio of hydrogen to methyl acetate fed to the hydrogenation unit is 5:1 to 20:1. The total molar ratio of methyl acetate to carbon oxide(s) fed to the hydrogenation unit is 1:2 to 100:1. The hydrogenation product stream is separated into a liquid stream containing ethanol, methanol, unreacted methyl acetate, water and ethyl acetate, and a gaseous stream containing unreacted hydrogen, carbon monoxide and carbon dioxide, and a portion of the gaseous stream is recycled to the hydrogenation unit.