Eggshell Catalyst for Selective Propylene Hydroformylation
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Solution Overview
Problem
Existing propylene hydroformylation processes face challenges with catalyst recovery, catalyst inactivation, and low selectivity of product aldehyde, particularly using rhodium-based homogeneous and biphasic technologies.
Innovation Solution
Development of an eggshell type catalyst with active components like Rh, Co, Ir, Ru, and Pd supported on a phosphine ligand resin pellet, featuring a 0.1-0.2 mm thick eggshell layer, prepared via excessive solution impregnation to ensure high selectivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If homogeneous catalysis or biphasic catalysis is used with rhodium complex, then the propylene hydroformylation reaction can proceed, but the rhodium catalyst is difficult to recover and prone to inactivation
Solution Approach 1:
The catalyst is segmented into a carrier core and an eggshell active layer containing rhodium complexes. This segmentation allows the catalyst to function as a heterogeneous catalyst that can be easily separated from the reaction mixture, while maintaining the high activity of homogeneous catalysts. The eggshell structure concentrates active components in the outer shell where mass transfer is most efficient.
Solution Approach 2:
The invention uses a composite catalyst structure combining a porous carrier material with rhodium complex active components. The carrier provides mechanical stability and ease of separation, while the rhodium complex provides catalytic activity. This composite approach resolves the contradiction between recoverability and reaction efficiency.
2Ease of operation
If TPPTS phosphine ligand is used in biphasic catalysis, then separation and recovery steps are simplified, but the catalyst becomes more prone to inactivation
Solution Approach 1:
The phosphine ligand distribution is optimized locally within the eggshell layer rather than uniformly throughout the entire catalyst particle. This local concentration of ligands in the active region enhances catalyst stability where it is most needed, while maintaining ease of separation provided by the heterogeneous structure.
3Productivity
If existing polyphase hydroformylation methods are used, then certain success is achieved, but catalyst active components are lost and product aldehyde selectivity is low
Solution Approach 1:
The eggshell catalyst utilizes a porous carrier structure with controlled pore size and distribution. The porous structure provides high surface area for active component dispersion, preventing aggregation and loss of catalytic activity. The pore architecture also influences product selectivity by controlling diffusion paths and transition state stabilization.
Solution Approach 2:
The invention optimizes multiple parameters including eggshell layer thickness, metal loading concentration, and phosphine ligand-to-metal ratio. By carefully controlling these parameters, the catalyst achieves both high activity and high selectivity for n-butyraldehyde while minimizing active component loss.
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 eggshell type catalyst achieves high selectivity and activity for n-butyraldehyde production, suitable for industrial applications with improved catalyst recovery and reduced inactivation, leveraging a controlled distribution of active components through a regulated porous structure.
Implementation Method 1
The phosphine ligand resin pellet is formed by autopolymerization of one or more than one of monodentate ligands of vinyl or copolymerization of monodentate ligands of vinyl and polydentate ligands of vinyl
Implementation Method 2
metal active components are coordinated on a surface layer of the polymer pellet to form a catalyst eggshell layer
Data Source
AI summary
An eggshell type catalyst, and a preparation method and application thereof in propylene hydroformylation reaction are provided. The eggshell type catalyst uses phosphine ligand resin pellets with developed pore structure as a carrier and one, two or more than two of metals Rh, Co, Ir, Ru and Pd as active components. The spatial distribution of the active metal components in the resin pellets is effectively regulated through a method of finely regulating the porous channel structure of the carrier resin pellets and adding competitive adsorption and coordination, so that the prepared eggshell type catalyst has the characteristics of high activity in the propylene hydroformylation reaction and good selectivity of n-butyraldehyde in the product aldehyde.