Supported Palladium Catalyst for Aromatic Dinitrile Hydrogenation
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Solution Overview
Problem
Current methods for producing aromatic ring-containing amino compounds by hydrogenating aromatic dinitrile compounds face challenges such as destabilization of catalytic activity, high production costs, and side reactions due to the use of liquid ammonia or palladium catalysts, which result in low yields and by-production of high-boiling products.
Innovation Solution
A method involving a supported palladium catalyst with palladium predominantly located on the outer surface of a carrier within a 200 µm depth, using an amide solvent and avoiding ammonia, to efficiently hydrogenate aromatic dinitrile compounds and minimize side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid ammonia is used as solvent for catalytic hydrogenation, then reaction selectivity is improved, but catalytic activity is destabilized and production cost increases
Solution Approach 1:
The patent changes the solvent parameter from liquid ammonia to organic solvent, and modifies the catalyst composition by adding aluminum oxide to the support. This parameter change resolves the contradiction by maintaining reaction selectivity while preventing catalyst dissolution and deactivation that occur in liquid ammonia.
Solution Approach 2:
The patent uses a composite catalyst system combining palladium on aluminum oxide support. This composite material structure prevents catalyst dissolution in organic solvents while maintaining high reaction selectivity, resolving the contradiction between selectivity and catalytic activity stability.
2Reliability
If liquid ammonia is used as solvent for catalytic hydrogenation, then reaction selectivity is improved, but apparatus complexity increases
Solution Approach 1:
The patent changes the solvent parameter from liquid ammonia to organic solvent, eliminating the need for high-pressure apparatus and complex vaporization/recovery systems. This parameter change resolves the contradiction by maintaining reaction selectivity while significantly simplifying apparatus requirements.
3Power
If palladium catalyst is used for hydrogenation in organic solvent, then catalytic activity is improved, but side reactions increase and yield decreases
Solution Approach 1:
The patent uses a composite catalyst system with palladium on aluminum oxide support. This composite structure enhances catalytic activity while the aluminum oxide support prevents unwanted side reactions, resolving the contradiction between high activity and low side reactions.
Solution Approach 2:
The patent modifies the local properties of the catalyst by using aluminum oxide support with specific surface characteristics. This local quality change selectively promotes the desired hydrogenation reaction while suppressing side reactions, resolving the contradiction between catalytic activity and reaction specificity.
4Reliability
If sponge-form catalyst is used for hydrogenation, then reaction selectivity is improved, but preparation complexity increases
Solution Approach 1:
The patent changes the catalyst form from sponge-form to conventional supported form on aluminum oxide. This parameter change maintains reaction selectivity while dramatically simplifying preparation procedures, eliminating the need for complex leaching and solvent replacement steps.
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 increases the yield of aromatic ring-containing amino compounds while reducing by-products, maintaining catalytic activity, and avoiding the need for costly ammonia and complex recovery processes.
Implementation Method 1
hydrogenating an aromatic dinitrile compound in an amide solvent in the presence of a solid catalyst
Implementation Method 2
hydrogenating an aromatic dinitrile compound... reducing at least one cyano group to an aminomethyl group
Data Source
Figure 1~2
AI summary
An aromatic dinitrile compound is hydrogenated in an amide solvent in the presence of a solid catalyst and in the absence of ammonia to produce an aromatic ring-containing amino compound by reducing at least one cyano group to aminomethyl group. The solid catalyst is a supported palladium catalyst in which palladium is substantially present on the outer surface of carrier and in a surface layer within a depth of 200 µm from the outer surface. Using such a solid catalyst, the aromatic dinitrile compound is efficiently hydrogenated to the aromatic ring-containing amino compound under mild conditions.