Silica Carrier Dissolution in Noble Metal Catalyst Oxidation
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Solution Overview
Problem
The existing methods for producing α, β-unsaturated carboxylic acid using silica-supported noble metal catalysts in water-containing solvents face a challenge where the silica carrier dissolves, leading to reduced catalyst activity over time.
Innovation Solution
The method involves supplying silicic acid or its ions into the reactor during the oxidation process of olefins or α, β-unsaturated aldehydes in the presence of a silica-supported noble metal catalyst, preventing the dissolution of the silica carrier in the water-containing solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silica-supported noble metal-containing catalyst is used in a water-containing solvent for oxidation, then the catalyst activity is initially high, but the silica carrier dissolves over time leading to reduced catalyst activity
Solution Approach 1:
The patent applies preliminary anti-action by adding silicic acid or its ions to the reaction system before the silica carrier dissolution problem occurs. This preventive measure creates a reservoir of silicic acid that compensates for the dissolving silica carrier, maintaining the silica balance and preventing catalyst activity loss. The silicic acid addition counteracts the harmful dissolution effect before it significantly impacts catalyst performance.
Solution Approach 2:
The patent changes the chemical parameter of the system by introducing silicic acid or its ions, which alters the silica equilibrium in the water-containing solvent. This parameter change prevents the net loss of silica from the carrier by establishing a dynamic balance where silicic acid can replenish dissolved silica, thereby maintaining catalyst integrity and activity throughout the reaction period.
2Productivity
If the reaction is maintained for a long time to improve productivity, then more product is formed, but the silica carrier dissolution increases leading to catalyst deactivation
Solution Approach 1:
By pre-adding silicic acid to the system, the patent creates a protective buffer that maintains catalyst integrity throughout extended reaction periods. This preliminary protective measure allows the reaction to proceed for longer durations without the catalyst deactivating due to silica loss, thereby enabling sustained high productivity over extended time frames.
Solution Approach 2:
The silicic acid addition ensures continuous maintenance of catalyst activity throughout the extended reaction period. By establishing a reservoir of silicic acid that continuously compensates for silica carrier dissolution, the catalyst maintains its structural integrity and catalytic function throughout the entire extended reaction duration, enabling uninterrupted productive operation.
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
This approach effectively suppresses the dissolution of the silica carrier, maintaining catalyst activity and improving the yield of α, β-unsaturated carboxylic acid in the liquid-phase oxidation process.
Implementation Method 1
a silica-supported noble metal-containing catalyst
Implementation Method 2
supplying at least one of silicic acid and ions thereof into the reactor... dissolution of a silica carrier... in a water-containing solvent can be suppressed
Data Source
AI summary
Disclosed is a method for producing an α, β-unsaturated carboxylic acid from an olefin or an α, β-unsaturated aldehyde, while suppressing dissolution of a silica carrier, which is a carrier for a silica-supported noble metal-containing catalyst, in a water-containing solvent. Specifically disclosed is a method for producing an α, β-unsaturated carboxylic acid through oxidation of an olefin or an α, β-unsaturated aldehyde in a water-containing solvent in the presence of a silica-supported noble metal-containing catalyst in a reactor, in which at least one of silicic acid and ions thereof is supplied into the reactor.