Bidentate Phosphite Nickel Catalysts for Stable Adiponitrile Yield
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Solution Overview
Problem
Existing catalyst systems for hydrocyanation and isomerization reactions, such as those using multidentate phosphite ligands, are not optimized for rapidity, selectivity, and stability, limiting their commercial potential in producing chemicals like adiponitrile.
Innovation Solution
Development of bidentate phosphite ligands and catalyst complexes comprising these ligands with transition metals, particularly nickel, for use in hydrocyanation and isomerization processes, optimized for improved efficiency and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multidentate phosphite ligands are used in catalyst systems, then catalytic activity is achieved, but selectivity and stability are not optimized
Solution Approach 1:
The patent modifies the ligand structure by changing from multidentate to bidentate phosphite ligands with specific substituents (aryl, alkyl, or heteroatom groups) at defined positions. This structural parameter change optimizes the electronic and steric properties of the ligand, thereby improving both catalyst stability and reaction rapidity simultaneously.
Solution Approach 2:
The catalyst system combines bidentate phosphite ligands with zero-valent nickel and Lewis acid promoters to create a composite catalytic system. This composite approach allows each component to contribute its strengths: the bidentate ligand provides stability through chelation, nickel provides catalytic activity, and the Lewis acid promoter enhances selectivity, resolving the contradiction between stability and productivity.
2Productivity
If existing catalyst systems are used for hydrocyanation, then adiponitrile production is achieved, but yield and selectivity are limited
Solution Approach 1:
The bidentate phosphite ligand introduces local electronic and steric modifications at specific positions (ortho substituents on the phenolic rings) that create a localized catalytic environment. This local quality enhancement directs the reaction pathway toward desired products (adiponitrile with >90% selectivity) while maintaining high productivity, resolving the contradiction between yield and selectivity.
Solution Approach 2:
The chelating bidentate ligand provides structural feedback to the nickel center, stabilizing the catalyst in its active form and preventing deactivation pathways. This feedback mechanism maintains high catalytic activity over extended periods, enabling sustained high yields of adiponitrile with excellent selectivity.
3Productivity
If catalyst systems are optimized for one reaction, then performance in that reaction improves, but versatility across multiple reactions decreases
Solution Approach 1:
The bidentate phosphite ligand structure with variable substituents (R1, R2, R3, R4) provides a universal platform that can be adapted to different catalytic reactions. By modifying the substituent groups, the same ligand framework can be optimized for hydrocyanation, isomerization, hydrogenation, hydroformylation, and other reactions, maintaining high efficiency across multiple applications while providing versatility.
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
Enhances the production of adiponitrile by improving the catalytic processes, achieving higher yields and selectivity in hydrocyanation and isomerization reactions.
Implementation Method 1
Bisphosphine, bisphosphite, and bis(phosphorus) ligands in general, contain two phosphorus donor atoms and normally form cyclic chelate structures with transition metals
Implementation Method 2
a catalyst complex comprising a bidentate phosphite ligand and at least one transition metal in a process for the hydrocyanation of an organic compound containing at least one olefinic group
Implementation Method 3
a catalyst complex comprising a bidentate phosphite ligand and at least one transition metal in a process for the isomerization of a monoethylenically unsaturated compound
Data Source
Figure 1
AI summary
A process for the hydrocyanation of an organic compound containing at least one olefinic group comprising reacting the organic compound with hydrogen cyanide in the presence of a catalyst complex comprising a bidentate phosphite ligand having one of the following structures:(I) and (II) and at least one transition metal.