Group VIII Metal Catalyst for Selective Hydrogenation
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Solution Overview
Problem
Current hydrocarbon conversion processes produce polyunsaturated compounds that must be eliminated to meet strict specifications for petrochemical and polymerization units, and existing selective hydrogenation catalysts face challenges in achieving optimal performance and selectivity.
Innovation Solution
A catalyst system comprising nanoparticles of Group VIII metals associated with oxy(hydroxy) cations from columns IIA, IIIA, IIIB, and IVA of the periodic table, supported on refractory oxides, with controlled particle size and distribution to enhance selective hydrogenation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional selective hydrogenation catalysts are used, then polyunsaturated compounds can be converted to alkenes, but total saturation occurs leading to formation of alkanes and reduced selectivity
Solution Approach 1:
The patent employs composite catalyst materials combining Group VIII metal nanoparticles (Pd, Pt, Ni, or Co) with oxy(hydroxide) cations (Mg, Ca, Al, Fe, Mn, Zn, or Cd) supported on refractory oxide surfaces. This composite structure creates synergistic effects where the metal nanoparticles provide hydrogenation activity while the oxy(hydroxide) cations modulate electron density and prevent over-hydrogenation, thereby maintaining high selectivity for alkenes and preventing alkane formation
2Reliability
If metal nanoparticle size is not controlled, then catalyst preparation is simpler, but catalytic activity and selectivity are reduced
Solution Approach 1:
The patent precisely controls the particle size of metal nanoparticles within the range of 1-5 nm through controlled impregnation parameters including solution concentration, pH, temperature, and drying conditions. This parameter optimization ensures high surface area to volume ratio for enhanced catalytic activity while maintaining uniform size distribution for consistent selectivity across the catalyst bed
Solution Approach 2:
The patent creates non-uniform distribution of metal nanoparticles on the support surface, with higher concentration at specific locations to optimize reactant contact. The oxy(hydroxide) cations are distributed to create local electronic environments that enhance hydrogenation selectivity at specific active sites, ensuring optimal performance throughout the catalyst structure
3Productivity
If Group VIII metal nanoparticles are used alone, then hydrogenation activity is achieved, but selectivity and performance are insufficient
Solution Approach 1:
The patent combines Group VIII metal nanoparticles with oxy(hydroxide) cations to create a composite catalyst system where the metal provides hydrogenation activity and the oxy(hydroxide) cations enhance selectivity through electronic effects and surface geometry control, achieving both high productivity and reliability simultaneously
Solution Approach 2:
The oxy(hydroxide) cations act as intermediaries between the metal nanoparticles and the hydrocarbon feedstock, modulating the electronic density of the metal surface and facilitating selective hydrogenation of polyunsaturated compounds to alkenes while preventing further hydrogenation to alkanes, thus mediating the reaction to achieve both activity and selectivity
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 catalyst system improves the performance and selectivity of selective hydrogenation reactions, achieving higher activity and selectivity for converting polyunsaturated compounds to corresponding alkenes while avoiding total saturation.
Implementation Method 1
The selective hydrogenation process has gradually become essential to eliminate polyunsaturated compounds from the C2 to C5 petroleum cuts mentioned because this process allows the conversion of the most unsaturated compounds to the corresponding alkenes while avoiding total saturation
Data Source
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AI summary
The invention relates to a process for preparing a catalyst precursor comprising the following steps: 1)a) preparing a colloidal solution A of defined pH containing oxy(hydroxy)de particles of a cation Mz+ selected from the group consisting of the cations of columns IIA, IIIA, IIIB, IVB and IVA of the periodic table or 1)b) using a commercial aqueous colloidal solution (solution A) of defined pH containing oxy(hydroxy)de particles of a cation Mz+ selected from the group consisting of the cations of columns IIA, IIIA, IIIB, IVB and IVA of the periodic table; 2) adding an aqueous solution B containing a precursor salt of a metal from group VIII having a concentration of 0.001 to 1 mol/liter, the metal precursor salt being soluble under the pH conditions used in step 1. The invention also relates to the catalyst obtained from the catalyst precursor and its application in selective hydrogenation.