Alkyl Methacrylate Production via Fixed Bed Catalyst
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Solution Overview
Problem
Current methods for producing alkyl methacrylates through oxidative esterification face challenges such as catalyst attrition, reduced space-time yield, and difficulty in separating byproducts like isobutyrates, which are formed in excess and are difficult to separate from the product stream.
Innovation Solution
A process using a heterogeneous noble metal-containing catalyst in a reactor system with specific conditions, including a noble metal catalyst with gold or palladium, titanium-containing particles, and a reactor configuration that optimizes the reaction conditions to limit byproduct formation, specifically controlling the concentration and ratio of reactants and catalyst properties to achieve efficient alkyl methacrylate production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If slurry catalysts of less than 200 μm size are used, then the oxidative esterification reaction can proceed, but catalyst attrition occurs which limits catalyst life and makes filtration difficult
Solution Approach 1:
The patent changes the particle size parameter from less than 200 μm (slurry catalyst) to 200-1000 μm (fixed bed catalyst), resolving the contradiction between reaction efficiency and catalyst stability. The larger particle size reduces attrition while maintaining catalytic activity through optimized porosity and surface area characteristics.
Solution Approach 2:
The patent extracts the catalyst from the liquid slurry phase and places it in a fixed bed configuration, separating the catalyst circulation system from the reaction system. This eliminates catalyst attrition and filtration issues while maintaining high conversion rates through continuous flow operation.
2Reliability
If larger size catalyst particles are charged to a fixed bed reactor to address attrition, then catalyst life is improved, but space-time yield is reduced
Solution Approach 1:
The patent employs porous catalyst particles with optimized pore size distribution and surface area-to-volume ratio. The porous structure provides high catalytic activity within larger particles, maintaining space-time yield while avoiding attrition problems associated with dense non-porous catalysts of similar size.
Solution Approach 2:
The patent implements a dynamic fixed bed system with optimized flow rates and temperature profiles that maximize catalyst utilization. The continuous flow regime ensures efficient mass transfer to the catalyst surface, maintaining high productivity despite larger particle sizes.
3Productivity
If methanol is provided in excess to maximize conversion of methacrolein, then conversion is improved, but separation and purification becomes more difficult due to increased byproduct formation
Solution Approach 1:
The patent optimizes the methanol-to-methacrolein ratio parameter to achieve high conversion without excessive excess methanol. By precisely controlling feed composition and reaction conditions, the process maximizes conversion while minimizing byproduct formation and simplifying downstream separation requirements.
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 enhances selectivity and reduces byproduct formation, improving the efficiency and purity of alkyl methacrylate production by controlling the concentration and ratio of reactants and catalyst properties, thereby increasing the space-time yield and reducing the amount of unwanted byproducts like isobutyrate in the product stream.
Implementation Method 1
reacting the methacrolein in an oxidative esterification reaction comprises introducing a reaction mixture comprising the methacrolein, an alcohol, and an oxygen-containing gas to a reactor system comprising a heterogeneous noble metal-containing catalyst
Implementation Method 2
the conversion of methacrolein and methanol in the presence of oxygen to methyl methacrylate
Data Source
AI summary
A process for the production of an alkyl methacrylate is disclosed, the method comprising: a) producing methacrolein from propionaldehyde and formaldehyde; and b) reacting the methacrolein in an oxidative esterification reaction to obtain the alkyl methacrylate. Reacting the methacrolein in an oxidative esterification reaction comprises introducing a reaction mixture comprising the methacrolein, an alkyl alcohol, and an oxygen-containing gas to a reactor system comprising a heterogeneous noble metal-containing catalyst. An average concentration of methacrolein in step b) is less than 40 wt % based on the total weight of alkyl alcohol and methacrolein. The reactor system of step d) has an average ratio of alkyl alcohol to methacrolein less than 20:1 based on an average amount of alkyl alcohol and methacrolein entering and exiting the system. A liquid phase stream exiting the reactor system contains at least 30 wt % alcohol based on the total weight of the liquid phase stream. The liquid phase stream exiting the reactor system contains less than 30 wt % methacrolein based on the total weight of the liquid phase stream. The liquid phase stream exiting the reactor system comprises greater than 0.1 ppm and less than 5000 ppm of an alkyl isobutyrate. A gas phase stream exiting the reactor system comprises between 1 mol % and 7.5 mol % oxygen based on the total amount of the gas phase stream. The alkyl alcohol is a straight or branched alcohol comprising from 1 to 12 carbon atoms.