Group VIII Metal Catalyst Preparation with Organic Additives
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Solution Overview
Problem
Existing selective hydrogenation catalysts face challenges in achieving high selectivity and activity, particularly in converting polyunsaturated hydrocarbons to corresponding alkenes while avoiding total saturation and formation of alkanes in petroleum cuts.
Innovation Solution
A catalyst with nickel as the active phase, supported on alumina, is prepared using a solution containing a nickel precursor and an organic additive with carboxylic acid functions, where the additive to nickel molar ratio is less than or equal to 1.5, followed by impregnation, drying, calcination, and reductive treatment, enhancing selectivity and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional selective hydrogenation catalysts are used, then high activity is achieved, but selectivity is insufficient leading to total saturation and alkane formation
Solution Approach 1:
The invention changes the chemical composition parameters of the catalyst by introducing organic compounds with specific functional groups (carboxylic acid, hydroxyl, amine, etc.) during the preparation process. These additive compounds modify the surface properties and electronic structure of the metal particles, thereby changing the catalytic selectivity to favor alkene production over alkane formation while maintaining high activity
Solution Approach 2:
The invention creates a composite catalyst system combining metal particles (Group VIII elements) with organic compound additives that remain on or interact with the metal surface. This composite structure provides both the high activity of the metal and the selectivity-modulating effect of the organic compounds, preventing total saturation while maintaining conversion efficiency
2Productivity
If metal particle size is reduced to increase activity, then catalytic activity improves, but selectivity control becomes more difficult
Solution Approach 1:
The invention applies local quality modification by introducing organic compound additives that specifically interact with the metal particle surfaces. These additives create localized chemical environments on the catalyst surface that enhance selectivity control, allowing small metal particles to maintain both high activity and improved selectivity through surface property modification rather than changing particle size distribution
3Manufacturing precision
If organic compounds are introduced during catalyst preparation, then selectivity is improved, but process complexity increases
Solution Approach 1:
The invention achieves universality by identifying a class of organic compounds with specific functional groups (carboxylic acid, hydroxyl, amine) that can be applied across different metal types (Group VIII elements) and catalyst formulations. This multi-functional approach allows the same preparation methodology to improve selectivity for various catalyst systems, reducing the need for highly specialized procedures for each case
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 process results in a catalyst with improved catalytic performance in selective hydrogenation, maintaining high activity while achieving enhanced selectivity in converting polyunsaturated hydrocarbons to alkenes, avoiding total saturation and alkane formation.
Implementation Method 1
at least one step of impregnating the solution prepared in step a) on said support
Implementation Method 2
said additive being an organic compound having one to three carboxylic acid functions
Implementation Method 3
at least one step of calcination of the dried support from step c) to obtain at least said nickel in oxide form
Implementation Method 4
The preparation process comprises in particular the preparation of a solution comprising at least one precursor of a Group VIII metal
Data Source
AI summary
The invention relates to a method for preparing a selective hydrogenation catalyst, the active phase of which includes at least one Group VIII metal, and at least one substrate consisting of at least one oxide, wherein said method includes: a) at least a step of preparing a solution containing at least one precursor of said Group VIII metal and at least one additive, said precursor and said additive being added during the preparation of the solution with an additive/Group VIII metal molar ratio of less than or equal to 1.5; b) at least a step of impregnating said substrate with the solution prepared in step a); c) at least a step of drying the impregnated substrate from step b); and d) at least a step of calcining the dried substrate from step c) so as to obtain at least said Group VIII metal in an oxide form. The invention also relates to a hydrogenation method implementing said catalyst. The additives are organic compounds having one to three carboxylic acid functions, preferably carboxylic acids selected from among glycine, aspartic acid, citric acid, and tartric acid. The catalyst obtained by this specific preparation method has catalytic performance that is enhanced in terms of selectivity while still having high activity.