Epoxidation Catalyst Promoter Composition for Selectivity Stability
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Solution Overview
Problem
Olefin epoxidation catalysts face challenges in maintaining selectivity and activity over time, leading to increased operating costs and reduced efficiency in olefin oxide production, as the fraction of converted olefin decreases with catalyst aging, requiring temperature increases to sustain production levels.
Innovation Solution
A catalyst comprising a carrier with silver, a rhenium promoter, a first co-promoter selected from sulfur, phosphorus, or boron, and a second co-promoter selected from tungsten, molybdenum, or chromium, with specific quantities and ratios, deposited in a manner that enhances initial selectivity and stability, allowing for improved catalytic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional epoxidation catalysts are used, then the catalyst can initially produce olefin oxide, but the selectivity and activity decrease over time as the catalyst ages, requiring temperature increases to maintain production levels
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating specific promoters (rhenium at greater than 1 mmole/kg, first co-promoter from sulfur/phosphorus/boron, second co-promoter from tungsten/molybdenum/chromium) in controlled quantities. This compositional modification enables the catalyst to maintain stable selectivity and activity over extended operation periods, resolving the contradiction between initial productivity and long-term reliability.
Solution Approach 2:
The patent creates a composite catalyst material combining silver (0.5-5 mmole/kg) with multiple promoters (rhenium, first co-promoter, second co-promoter) on a carrier. This composite structure synergistically enhances both the initial activity and the temporal stability of the catalyst, allowing sustained olefin oxide production without the selectivity decay typical of conventional single-component or simpler multi-component catalysts.
2Duration of action of stationary object
If the catalyst operates for extended periods, then production continuity is maintained, but the fraction of converted olefin decreases, requiring temperature increases that may reduce selectivity
Solution Approach 1:
The patent applies preliminary action by pre-configuring the catalyst with optimal promoter combinations and quantities during the catalyst preparation stage. The rhenium promoter at greater than 1 mmole/kg and the specific co-promoters are deposited in controlled amounts to pre-establish the catalyst's stability characteristics, enabling it to resist deactivation mechanisms throughout extended operation without requiring subsequent adjustments.
Solution Approach 2:
The patent introduces dynamics by enabling the catalyst to adapt to aging effects through its promoted structure. The multiple promoters work synergistically to dynamically counteract deactivation processes, allowing the catalyst to maintain stable performance characteristics over time rather than following the typical decay trajectory of conventional catalysts.
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 described catalyst configuration achieves an unexpected improvement in initial selectivity and stability, extending the catalyst's operational effectiveness and reducing yearly operating costs by maintaining high olefin oxide production levels without the need for frequent temperature adjustments.
Implementation Method 1
a catalyst for the epoxidation of an olefin comprising a carrier and, deposited on the carrier, silver, a rhenium promoter, a first co-promoter, and a second co-promoter
Data Source
AI summary
A catalyst for the epoxidation of an olefin comprising a carrier and, deposited on the carrier, silver, a rhenium promoter, a first co-promoter, and a second co-promoter; wherein the quantity of the rhenium promoter deposited on the carrier is greater than 1 mmole/kg, relative to the weight of the catalyst;the first co-promoter is selected from sulfur, phosphorus, boron, and mixtures thereof; the second co-promoter is selected from tungsten, molybdenum, chromium, and mixtures thereof; andthe total quantity of the first co-promoter and the second co-promoter deposited on the carrier is at most 3.8 mmole/kg, relative to the weight of the catalyst;a process for preparing the catalyst; a process for preparing an olefin oxide by reacting a feed comprising an olefin and oxygen in the presence of the catalyst; and a process for preparing a 1,2-diol, a 1,2-diol ether, a 1,2-carbonate, or an alkanolamine.