Cu/MMgOx Interfacial Catalyst for Selective Alkyne Hydrogenation
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Solution Overview
Problem
Current catalysts for selective acetylene hydrogenation face challenges such as catalyst poisoning, deactivation due to green oil formation, and difficulty in controlling the selectivity and stability of the reaction, particularly with precious metal catalysts like Pd, and non-precious metals like Ni, which suffer from low activity and rapid deactivation.
Innovation Solution
The development of a Cuy/MMgOx catalyst with a controllable interface structure using layered double hydroxides (LDHs) as precursors, where Cu is evenly dispersed on the MMgOx carrier, allowing for precise control of the electronic and geometric structure through a nucleation/crystallization isolation method and topotactic transformation, enhancing catalytic activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Pd-based catalyst is used for selective acetylene hydrogenation, then catalytic activity is improved, but ethylene selectivity deteriorates due to easy desorption and further hydrogenation to ethane
Solution Approach 1:
The patent introduces a metal-oxide interface structure as an intermediary between the metal catalyst and the reaction. The interface structure modifies the electronic state of metal atoms, creating electron-deficient metal sites that alter the adsorption behavior of ethylene, preventing its easy desorption and subsequent hydrogenation to ethane, thus improving selectivity while maintaining activity
Solution Approach 2:
The patent changes the electronic parameter of the catalyst by creating metal-oxide interfaces, which modify the electron density and distribution of metal atoms. This parameter change transforms the catalyst's interaction with reactants, allowing selective hydrogenation of acetylene while controlling ethylene desorption to prevent over-hydrogenation
2Quantity of substance
If Ni-based catalyst is used for selective acetylene hydrogenation, then cost is reduced by using non-precious metal, but catalytic activity deteriorates due to rapid deactivation from green oil formation
Solution Approach 1:
The metal-oxide interface structure acts as an intermediary that modifies the electronic state of Ni atoms, creating electron-deficient sites that reduce the tendency of acetylene to polymerize into green oil. This interface structure prevents catalyst deactivation while maintaining sufficient catalytic activity, making Ni-based catalysts viable alternatives to precious metals
Solution Approach 2:
The patent changes the electronic parameter of Ni atoms by forming metal-oxide interfaces, which alter the d-band center and electron density. This parameter modification suppresses the polymerization reaction pathway while preserving the hydrogenation pathway, thereby preventing green oil formation and catalyst deactivation
3Reliability
If traditional interface structure preparation method is used, then ethylene selectivity is improved, but catalytic activity deteriorates due to difficult control of deposited species thickness leading to overburdening of active sites
Solution Approach 1:
The patent uses layered double hydroxides (LDHs) as precursors that pre-organize the metal and oxide components in a controlled structure. This preliminary arrangement ensures that during thermal treatment, the metal-oxide interface forms with precise thickness and distribution, preventing overburdening of active sites while maintaining high selectivity and activity
Solution Approach 2:
The patent precisely controls the thickness parameter of the deposited oxide layer by adjusting the LDH precursor composition and thermal treatment conditions. This parameter control ensures optimal interface structure that maintains both high ethylene selectivity and catalytic activity by preventing excessive coverage of metal active sites
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 Cuy/MMgOx catalyst achieves high conversion rates and selectivity in acetylene hydrogenation with improved stability, avoiding the issues of catalyst deactivation and allowing for precise control of the reaction, thus overcoming the limitations of traditional catalysts.
Implementation Method 1
Taking LDHs as the precursor, the catalyst with the Cuy-MMgOx interface structure is fabricated through the topotactic transformation in the process of heat treatment
Implementation Method 2
the process of heat treatment
Implementation Method 3
The mixed salt solution and alkali solution are nucleated momentarily by nucleation/crystallization isolation method, synthesizing the layer double hydroxides (LDHs) with controllable size of ecological particle
Implementation Method 4
nucleation/crystallization isolation method
Implementation Method 5
the active metal component Cu is evenly dispersed on the surface of MMgOx
Data Source
AI summary
Cuy/MMgOx interfacial catalyst for selective alkyne hydrogenation and its preparation method are disclosed. The preparation method of the catalyst includes: the mixture of salt and alkali solution is nucleated momentarily by nucleation/crystallization isolation method, preparing the composite metal hydroxide CuyMMg4-LDHs as precursor, which has typical hexagonal morphology of the double hydroxide; the precursor is topologically transformed by heat treatment to produce unsaturated oxide; the catalyst with Cuy-MMgOx interface structure is prepared by separating and electronically modifying Cu particles. By adjusting the ratio of Cu2+/M3+ in LDHs, the electronic and geometric structure of Cuy-MMgOx interface can be flexibly controlled, thus enhancing the reaction activity, product selectivity and stability. The catalyst can be used in the selective hydrogenation of various alkynes in the fields of petrochemical and fine chemical industry, with the outstanding catalytic activity and C═C double bond selectivity. The catalyst also has good reusability.