Melonal Production via Tin Zeolite Catalysis
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Solution Overview
Problem
Current methods for the Baeyer-Villiger oxidation of citral with hydrogen peroxide face challenges such as complex catalyst synthesis, long reaction times, and low selectivity, particularly due to the use of a 1:1 mixture of geranial and neral, which complicates scale-up and efficiency.
Innovation Solution
A process utilizing a tin-containing molecular sieve catalyst, specifically a zeolitic material with a BEA framework structure, where the citral starting material consists of more than 50% trans-citral (geranial), optimizing the reaction conditions to enhance selectivity and reduce reaction time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a 1:1 mixture of geranial and neral is used as starting material, then the process follows conventional methodology, but the reaction time increases and selectivity decreases
Solution Approach 1:
The invention changes the compositional parameter of the starting material from a 1:1 mixture of geranial and neral to a mixture containing more than 50% geranial (优选 70-95%). This parameter change in the substrate composition leads to improved reaction kinetics and higher selectivity for the desired Baeyer-Villiger oxidation product, resolving the contradiction between reaction time and selectivity
2Reliability
If a tin-containing molecular sieve catalyst is used, then catalytic activity is achieved, but the catalyst synthesis becomes complex and scale-up difficult
Solution Approach 1:
The invention employs a tin-containing molecular sieve (zeolite) catalyst with specific porous structure (e.g., BEA framework). The porous structure provides well-defined active sites that ensure high catalytic activity and selectivity. The standardized synthesis approach using available zeolite frameworks and tin salts makes the catalyst more amenable to scale-up compared to previously complex synthetic routes
3Ease of manufacture
If conventional catalyst synthesis methods are used, then catalyst is obtained, but the synthesis time is long and scale-up is difficult
Solution Approach 1:
The invention uses pre-synthesized zeolite frameworks (such as BEA-type zeolites) as starting materials, which are commercially available or can be prepared using established industrial processes. This preliminary preparation of the support structure eliminates the need for complex in-situ catalyst synthesis, significantly reducing synthesis time and improving scale-up feasibility while maintaining high catalytic activity
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 significantly improves the selectivity and reaction efficiency, allowing for a more streamlined and effective industrial-scale production of melonal by using a higher percentage of trans-citral, thereby overcoming the limitations of previous methods.
Implementation Method 1
oxidizing a compound of formula (I) of which more than 50 % are present as compound of formula (Ia) with hydrogen peroxide in the presence of a catalyst comprising a tin-containing molecular sieve, obtaining a reaction mixture comprising a compound of formula (II) and optionally the compound of formula (III)
Implementation Method 2
in the presence of a catalyst comprising a tin-containing molecular sieve
Data Source
AI summary
A process for preparing 2,6-dimethyl-5-heptenal, comprising oxidizing citral of which more than 50 % are present as geranial with hydrogen peroxide in the presence of a catalyst comprising a Baeyer-Villiger oxidation catalyst, preferably a tin-containing molecular sieve.