Pd-Au Catalyst for Allyl Acetate Production
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Solution Overview
Problem
Existing catalysts for allyl acetate production suffer from significant activity reduction and decreased selectivity when switching from ethylene to propylene as a starting material, limiting efficient production.
Innovation Solution
A catalyst comprising palladium, gold, a compound containing copper, nickel, or zinc, and an alkali metal salt supported on a carrier, with a specific gold-to-palladium mass ratio of 2.0-3.5 parts by mass, is used in a process involving steps of solution preparation, impregnation, reduction treatment, and further support of the catalyst components to maintain activity and enhance selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts containing palladium and alkali metals are used for allyl acetate production from propylene, then the catalyst shows acceptable initial activity, but the activity significantly reduces over time and selectivity decreases
Solution Approach 1:
The patent applies composite materials by combining multiple metal components (palladium, gold, copper, nickel, zinc, or cobalt) with alkali metal salts on a carrier to create a multi-functional catalyst system. This composite structure maintains catalytic activity and selectivity over time, resolving the contradiction between reliability and productivity by preventing deactivation while sustaining high production efficiency.
Solution Approach 2:
The patent changes the chemical composition parameters of the catalyst by introducing specific ratios of gold (2.0-3.5 parts by mass per 100 parts by mass of palladium) and alkali metal salts (potassium acetate, sodium acetate, or cesium acetate). These parameter changes stabilize the catalyst structure and prevent sintering, thereby maintaining activity stability without sacrificing productivity.
2Productivity
If the catalyst composition is optimized for ethylene conversion, then high activity is achieved for ethylene, but the catalyst performance significantly diminishes when switching to propylene
Solution Approach 1:
The patent achieves universality by designing a catalyst formulation that performs effectively with both ethylene and propylene as starting materials. The combination of palladium with gold and alkali metal salts creates active sites that are versatile for different olefin substrates, resolving the contradiction between high productivity for a specific substrate and adaptability to multiple substrates.
Solution Approach 2:
The patent modifies the catalyst composition parameters by incorporating gold in specific amounts (2.0-3.5 parts by mass per 100 parts by mass of palladium) and alkali metal salts, which adjusts the electronic and geometric properties of the active sites. This enables the catalyst to maintain high activity and adaptability across different starting materials including both ethylene and propylene.
3Reliability
If more catalyst components are added to improve activity, then catalyst activity increases, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies local quality by concentrating the active components (palladium, gold, and alkali metal salts) on the carrier surface in specific locations where they can maximize their catalytic function. This targeted distribution maintains high activity while avoiding unnecessary complexity in the overall catalyst structure.
Solution Approach 2:
The patent optimizes the concentration parameters of each catalyst component, specifying precise amounts such as gold at 2.0-3.5 parts by mass per 100 parts by mass of palladium and alkali metal salts at controlled levels. This parameter optimization ensures sufficient activity without excessive complexity in the formulation.
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 maintains minimal reduction in activity and improves selectivity, leading to lower production costs and more efficient allyl acetate production, as demonstrated by retention and selectivity graphs showing superior performance compared to comparative examples.
Implementation Method 1
contacting the solution with the (e) carrier to support both compounds on the carrier
Implementation Method 2
contacting (f) an alkali solution with the carrier obtained in step 1 for impregnation
Implementation Method 3
reduction treatment of the carrier obtained in step 2
Implementation Method 4
supporting (c) a compound containing at least one element selected from copper, nickel, zinc and cobalt and (d) an alkali metal salt compound on the carrier obtained in step 3
Data Source
AI summary
An allyl acetate production catalyst comprising at least (a) palladium, (b) gold, (c) a compound containing at least one element selected from copper, nickel, zinc and cobalt, (d) an alkali metal salt compound and (e) a carrier, is produced by a process comprising step 1 in which a homogeneous solution of a palladium-containing compound and a gold-containing compound is supported on a carrier by contact therewith, step 2 in which the carrier obtained in step 1 is contacted with an alkali solution for impregnation, step 3 in which the carrier obtained in step 2 is subjected to reduction treatment, and step 4 in which a compound containing at least one element selected from copper, nickel, zinc and cobalt and an alkali metal salt compound are supported onto the carrier obtained in step 3. The obtained allyl acetate production catalyst has minimal reduction in activity and improved selectivity, when used for production of allyl acetate from propylene, oxygen and acetic acid.