Iron Catalyst Decarboxylative Cross-Ketonisation Selectivity

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Solution Overview

Problem

Current processes for catalytic decarboxylative cross-ketonisation of aryl and aliphatic carboxylic acids face challenges such as low selectivity, high metal usage, costly purification steps, and the need for expensive nanoparticles and high-boiling solvents, leading to inefficient and costly industrial-scale production of aryl aliphatic ketones.

Innovation Solution

A process using a metal catalyst in catalytic amounts, where the metal is present in a specific range relative to the carboxylic acids, operates without solvents, and involves controlled temperature and addition cycles to achieve high yields and selectivity of aryl aliphatic ketones, reducing the need for additional processing steps and costly reagents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If Mn(II) salts are used as catalyst in decarboxylative cross-ketonisation, then selectivity to aryl aliphatic ketone is improved (98%), but the process requires toxic metal salts and complex implementation (hydrogen/steam stream, high temperature, acidic media)

Engineering Contradiction:

Improveselectivity to aryl aliphatic ketoneVSAvoidcomplex implementation requirements

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces toxic Mn(II) salts with inexpensive iron powder, a cheap and non-toxic material. The iron catalyst is used in small amounts (0.03-0.1 equivalents) and can be easily removed by filtration, eliminating the need for complex purification procedures required by Mn salts while maintaining high selectivity

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent removes the harmful components (toxic Mn salts, acidic media, hydrogen/steam stream) from the reaction system while retaining the beneficial outcome (high selectivity). The reaction is conducted under milder conditions using iron powder as catalyst, extracting the toxicity and complexity from the process

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of operation

If Fe metal is used in stoichiometric amount for decarboxylative cross-ketonisation, then the process is simpler to implement, but the amount of metal used is excessive and yields are not quantitative

Engineering Contradiction:

Improvesimplicity of implementationVSAvoidamount of metal used

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The patent changes the quantity parameter of iron from stoichiometric amounts to catalytic amounts (0.03-0.1 equivalents), reducing the metal usage by more than 90% compared to stoichiometric procedures while maintaining simplicity of operation. This parameter change transforms the process from metal-intensive to catalyst-based

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If alumina Al2O3 is used as catalyst in decarboxylative cross-ketonisation, then the process is simple to conduct, but selectivity is poor (only 30% stearophenone)

Engineering Contradiction:

Improvesimplicity of process conductVSAvoidselectivity to aryl alkyl ketone

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent changes the chemical nature of the catalyst from alumina (inorganic oxide) to iron powder (metal), which fundamentally alters the reaction pathway and selectivity. This parameter change enables high selectivity (98% or better) while maintaining operational simplicity through easy filtration and mild reaction conditions

Inventive Principle:

Principle #35Parameter changes

4Productivity

If high temperature and acidic media are used in decarboxylative cross-ketonisation with Mn(II), then the reaction proceeds efficiently, but the process becomes detrimental for industrialization due to safety and cost concerns

Engineering Contradiction:

Improvereaction efficiencyVSAvoidindustrialization drawbacks

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful combination of high temperature and acidic media into a benign process by using iron powder catalyst that enables reaction under milder conditions. The iron catalyst promotes decarboxylation without requiring harsh acidic environments, transforming a harmful process into a safe and industrially viable one

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 process achieves yields of at least 70% and selectivity of up to 99% for aryl aliphatic ketones, simplifying downstream processes and reducing costs by eliminating the need for solvents and nanoparticles, while being more industrially viable.

Implementation Method 1

a catalytic amount of a metal, wherein the number of moles of the metal in the mixture is at least equal to 90% of the sum of the number of moles of aryl carboxylic acid and the number of moles of aliphatic carboxylic acid divided by the valency of the metal

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentEP3415493B1Process for the catalytic decarboxylative cross-ketonisation of aryl- and aliphatic carboxylic acids

Publication Date: 2020.01.01 RHODIA OPERATIONS SAS

AI summary

A 2-step process for the cross-ketonization (Piria reaction) between an aryl carboxylic acid and an aliphatic carboxylic acid using a metal-based compound characterized in that no external solvent is used during the reaction and a good selectivity, up to 99 mol %, toward the aryl aliphatic ketone may be obtained using a slight or a moderate excess of aryl carboxylic acid.