Heterogeneous Catalyst Noble Metal Gradient for Selectivity
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Solution Overview
Problem
Existing methods for preparing methyl methacrylate from methacrolein and methanol using heterogeneous catalysts with noble metals do not achieve optimal selectivity due to insufficient concentration of noble metals near the surface, particularly in larger catalyst particles.
Innovation Solution
A method involving a heterogeneous catalyst with a support and noble metals, where at least 90 wt% of the noble metal is concentrated in the outer 70% of the catalyst volume, and the catalyst has an average diameter of at least 200 microns, is used in a reactor with a controlled oxygen concentration, optimizing the distribution and location of noble metals for enhanced selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If larger catalyst particles are used, then selectivity is improved, but noble metal concentration near the surface becomes insufficient
Solution Approach 1:
The patent applies local quality by concentrating noble metals specifically in the outer 70% of the catalyst particle volume rather than uniform distribution. This creates a gradient structure where the outer regions have high noble metal concentration for selective reactions, while the inner core provides structural support. This resolves the contradiction by ensuring sufficient noble metal concentration near the surface of larger particles to maintain high selectivity.
2Manufacturing precision
If noble metals are concentrated in the outer region, then selectivity is improved, but catalyst manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary action by pre-forming the support particles to specific size ranges (200-500 microns) before noble metal deposition. This pre-preparation of support structures with appropriate porosity and surface area enables subsequent uniform noble metal distribution in the outer 70% volume. The stepwise approach simplifies manufacturing by breaking down the complex task of creating concentrated surface catalysts into manageable sequential operations.
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 approach significantly improves the selectivity and efficiency of methyl methacrylate production by ensuring a high concentration of noble metals near the surface, leading to higher yields and reduced impurities, while maintaining process safety by managing oxygen concentrations within safe limits.
Implementation Method 1
contacting in a reactor a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein said catalyst has an average diameter of at least 200 microns and at least 90 wt % of the noble metal is in the outer 70% of catalyst volume
Implementation Method 2
at least 90 wt % of the noble metal is in the outer 70% of catalyst volume
Data Source
AI summary
A method for preparing methyl methacrylate from methacrolein and methanol. The method comprises contacting a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein said catalyst has an average diameter of at least 200 microns and at least 90 wt % of the noble metal is in the outer 70% of catalyst volume, and wherein oxygen concentration at a reactor outlet is from 0.5 to 7.5 mol %.