Gold Catalyst Oxidative Esterification Oxygen Control

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Solution Overview

Problem

Existing methods for the oxidative esterification of methacrolein to methyl methacrylate face challenges in maintaining high catalyst activity and selectivity, especially at high methacrolein concentrations, with issues of catalyst deactivation, polymerization, and loss of valuable materials due to inadequate oxygen concentration control.

Innovation Solution

A continuous process using a gold-containing catalyst in a reactor system with controlled oxygen concentration below the explosion limit, maintaining a molar ratio of alkyl alcohol to methacrolein less than 15:1 and oxygen concentration less than 4 vol% in the gas phase, optimizing reactor design for minimal polymerization and extended catalyst life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high methacrolein concentrations are used to increase productivity, then reaction efficiency improves, but catalyst deactivation and polymerization increase

Engineering Contradiction:
Improvereaction efficiencyVSAvoidcatalyst lifetime
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the oxygen concentration (maintaining below explosion limit and <7 vol% in exhaust gas) and the molar ratio of alkyl alcohol to methacrolein (less than 15:1, particularly less than 10:1). These parameter optimizations enable the system to process high methacrolein concentrations while preventing catalyst deactivation and polymerization, thus resolving the contradiction between productivity and reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control by continuously monitoring and adjusting the oxygen concentration and molar ratio parameters to maintain optimal reaction conditions. This feedback mechanism ensures that high methacrolein concentrations are processed efficiently while preventing the formation of harmful byproducts and catalyst deactivation, thereby maintaining both high productivity and catalyst lifetime

Inventive Principle:
Principle #23Feedback

2Productivity

If oxygen concentration is increased to improve reaction rate, then productivity increases, but catalyst deactivation accelerates

Engineering Contradiction:
Improvereaction rateVSAvoidcatalyst lifetime
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent optimizes the oxygen concentration parameter by maintaining it below the explosion limit and ensuring less than 7 vol% in the exhaust gas. This precise parameter control enables sufficient reaction rate for high productivity while preventing excessive oxygen from causing catalyst deactivation, thus resolving the contradiction between reaction rate and catalyst lifetime

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary anti-action by pre-controlling the oxygen concentration to prevent catalyst deactivation before it occurs. By maintaining oxygen levels below critical thresholds and optimizing the molar ratio of alkyl alcohol to methacrolein, the system prevents oxidative damage to the catalyst while still achieving high reaction rates, thereby protecting catalyst lifetime while maintaining productivity

Inventive Principle:
Principle #9Preliminary anti-action

3Loss of energy

If molar ratio of alkyl alcohol to methacrolein is reduced to below 10:1 for energy efficiency, then separation energy decreases, but catalyst performance deteriorates

Engineering Contradiction:
Improveseparation energyVSAvoidcatalyst activity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the molar ratio of alkyl alcohol to methacrolein to be less than 15:1, particularly less than 10:1. Combined with precise oxygen concentration control (below explosion limit, <7 vol% in exhaust gas), this parameter optimization enables the system to achieve energy-efficient separation while maintaining high catalyst activity and selectivity, thus resolving the contradiction between energy loss and catalyst performance

Inventive Principle:
Principle #35Parameter changes

4Reliability

If high alkyl alcohol concentrations are used to maintain catalyst activity, then catalyst lifetime improves, but material loss increases

Engineering Contradiction:
Improvecatalyst lifetimeVSAvoidmaterial loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent optimizes the molar ratio parameter by maintaining it below 15:1, particularly below 10:1, while simultaneously controlling oxygen concentration below critical levels. This parameter optimization enables the system to maintain sufficient catalyst activity and lifetime while minimizing the excess alkyl alcohol that would otherwise be lost during separation, thus resolving the contradiction between catalyst lifetime and material loss

Inventive Principle:
Principle #35Parameter changes

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 high catalyst activity and selectivity, minimizes catalyst consumption, and reduces volatile substance losses, ensuring a long and stable reaction with improved yield and safety, while being cost-effective and environmentally friendly.

Implementation Method 1

a gold-containing catalyst, wherein the reactor has at least one gas inlet and at least one exhaust gas outlet

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

oxidative esterification of methacrolein with an alkyl alcohol and oxygen to form an alkyl methacrylate

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP3621943B1Method for oxidative esterification of aldehydes to carboxylic acid esters
Publication Date: 2023.01.18 ROHM GMBH
  • EP3621943B1 patent drawingFigure 1

AI summary

The present invention relates to a novel process for carrying out a heterogeneously catalyzed reaction for the oxidative esterification of aldehydes to carboxylic acid esters. In this context, the process according to the invention allows the reliable operation of processes of this type for longer and with constant or even increased activities and selectivities. As a result, it is possible to carry out processes of this type in as simple, economical and environmentally friendly a manner as possible.