Eggshell Noble Metal Catalyst for Long-Life Oxidative Esterification
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Solution Overview
Problem
Existing catalysts for producing methyl methacrylate suffer from reduced catalytic activity over time, necessitating the development of a more durable and long-lasting catalyst for oxidative esterification processes.
Innovation Solution
A catalyst comprising noble metal particles, particularly gold, with an average diameter of less than 15 nm, dispersed on the outer surface of titanium-containing particles and supported by a refractory oxide, forms an eggshell structure, ensuring at least 20% of the noble metal particles are adjacent to titanium-containing particles, maintaining high catalytic activity for extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing heterogeneous catalysts are used for oxidative esterification, then the production of methyl methacrylate is achieved, but the catalytic activity decreases over time requiring frequent replacement
Solution Approach 1:
The catalyst is segmented into distinct functional regions: an outer shell containing noble metal particles (0.1-3 wt%) for catalytic activity, and an inner core of titanium-containing oxide (25-99.8 wt%) for structural stability. This segmentation allows each component to perform its optimal function while protecting the overall catalyst structure during extended operation.
Solution Approach 2:
The catalyst employs local quality by concentrating the noble metal particles specifically in the outer region of the catalyst particle, where they are most needed for catalytic activity. The inner core provides different properties (mechanical strength and thermal stability) than the outer shell, optimizing both performance and durability in different spatial zones.
2Productivity
If noble metal particles are dispersed on the outer surface of support, then catalytic activity is enhanced, but particle aggregation may occur reducing effectiveness
Solution Approach 1:
The titanium-containing oxide particles act as an intermediary support structure that prevents direct aggregation of noble metal particles. The intermediary titanium oxide maintains stable dispersion of the active noble metal particles on the outer surface, ensuring sustained catalytic activity without degradation from particle clumping during extended operation.
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 catalyst maintains at least 75% of its initial activity after 100 hours, and up to 95% after 10,000 hours of use, significantly extending the lifespan and efficiency of the oxidative esterification process.
Implementation Method 1
a catalyst comprising noble metal particles and titanium-containing particles, wherein the noble metal particles and titanium-containing particles are disposed on an outer surface of a support
Implementation Method 2
at least 20% by weight of the total weight of noble metal particles are adjacent to at least one titanium-containing particle
Data Source
AI summary
A catalyst comprising noble metal particles and titanium-containing particles. The noble metal particles and titanium-containing particles are disposed on an outer surface of a support. At least 20% by weight of the total weight of noble metal particles are adjacent to at least one titanium-containing particle. The noble metal particles have an average diameter of less than 15 nm, and the catalyst has an average diameter of at least 200 microns. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.