Mixed Oxide Catalyst Composition for Olefin Oxidation

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Solution Overview

Problem

Current catalysts for the oxidation of olefins to produce acrolein and acrylic acid face challenges in achieving high propene conversion and product selectivity, with existing methods often resulting in by-products and inefficient heat management, leading to suboptimal yields and reactor design complexities.

Innovation Solution

A mixed oxide catalyst with the formula (Mo12BiaCb(Co+Ni)cDdEeFfGgHh)Ox is developed, where specific metal elements and molar ratios are used in controlled precipitation and calcination processes to create a catalytically active solid with improved selectivity and activity, allowing for high propene conversions and product yields when used in gas phase oxidation reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional mixed oxide catalysts are used for olefin oxidation, then propene conversion can be increased, but product selectivity deteriorates due to formation of by-products

Engineering Contradiction:
Improvepropene conversionVSAvoidproduct selectivity
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent applies parameter changes by precisely controlling the chemical composition parameters of the mixed oxide catalyst, specifically setting the molar ratios of Mo (12-20), Bi (0.5-5.0), Co (2-15), Ni (2-15), and other metals within defined ranges. This compositional parameter optimization enables simultaneous achievement of high propene conversion (>95%) and high product selectivity (≥88%) by tuning the catalytic active sites to favor desired oxidation products while minimizing by-product formation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by creating a multi-component mixed oxide catalyst system combining Mo, Bi, Co, Ni, and additional metals (Fe, Mn, Cu, Zn, Al, Si) in specific proportions. This composite structure leverages synergistic effects between different metal elements to achieve both high activity for propene conversion and high selectivity for acrolein/acrylic acid products, resolving the contradiction between productivity and substance loss.

Inventive Principle:
Principle #40Composite materials

2Productivity

If catalyst activity is increased to improve productivity, then propene conversion increases, but heat management becomes more difficult leading to reduced selectivity

Engineering Contradiction:
Improvepropene conversionVSAvoidheat management
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent addresses heat management through parameter changes in the catalyst composition, specifically incorporating heat-dissipating metal elements and optimizing the overall composition to control reaction exothermicity. The defined molar ratios of Bi, Co, Ni, and other metals are selected to modulate the catalytic activity and heat generation, enabling high propene conversion while maintaining temperature control to preserve product selectivity.

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If complex catalyst formulations are used to improve selectivity, then product yield increases, but manufacturing complexity increases

Engineering Contradiction:
Improveproduct selectivityVSAvoidmanufacturing complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent simplifies manufacturing by establishing clear parameter ranges for catalyst formulation: Mo (12-20), Bi (0.5-5.0), Co (2-15), Ni (2-15), and other metals within specified proportions. These defined parameters provide straightforward guidance for catalyst preparation, avoiding overly complex formulation procedures while achieving high selectivity (≥88%) through systematic compositional control.

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 catalyst achieves propene conversions greater than 95% and product selectivity of at least 88%, enhancing the economic viability of the process and reducing the formation of by-products, while allowing for efficient use in fixed bed reactors or coated on reactor walls.

Implementation Method 1

The invention relates to mixed oxide catalysts for the catalytic gas phase oxidation of olefins or methylated aromatics

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

the catalytic gas phase oxidation of olefins or methylated aromatics... the highly exothermic reaction of propene to give acrolein and acrylic acid

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

drying of the suspension, comminution of the dried material, mixing of the material with a sublimable substance, especially urea for pore generation, which is removed in the calcination

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentUS8008227B2Mixed oxide catalysts for the catalytic gas-phase oxidation of olefins and processes for producing them
Publication Date: 2011.08.30 EVONIK OPERATIONS GMBH

AI summary

The invention relates to mixed oxide catalysts for the catalytic gas-phase oxidation of olefins and methylated aromatics, processes for producing the catalysts and the reaction with air or oxygen in the presence of inert gases in various ratios at elevated temperatures and pressure to form aldehydes and carboxylic acids.