Ozonide Quenching via Bronsted Base Disproportionation
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Solution Overview
Problem
Ozonolysis of alkenes often results in uncontrolled thermal decomposition of secondary ozonides, leading to variable and unselective product mixtures due to the high exothermic nature of peroxide bond decomposition, making it difficult to produce desired carbonyl products like aldehydes and carboxylic acids in high yield without over-reduction or chemical incompatibilities.
Innovation Solution
The use of Bronsted bases, such as hydroxide and carboxylate bases, for non-reductive quenching of ozonides to yield aldehyde, ketone, and carboxylic acid products, eliminating the need for reducing or oxidizing agents and reducing the risk of over-reduction, thereby simplifying and cost-effectively producing desired carbonyl products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional reducing agents are used to quench ozonides, then carbonyl products can be obtained, but over-reduction occurs converting aldehydes to alcohols
Solution Approach 1:
The patent introduces an organic acid as an intermediary substance that mediates the quenching of ozonides. The acid reacts with the ozonide to form a peroxycarboxylic acid intermediate, which then decomposes to give carbonyl products without requiring strong reducing agents. This intermediary mechanism prevents over-reduction while maintaining reaction efficiency.
Solution Approach 2:
The patent changes the chemical environment by introducing organic acids to alter the reaction pathway. By adjusting parameters such as acid type, concentration, and temperature, the reaction can be controlled to achieve selective carbonyl formation without over-reduction, transforming the reaction conditions from harsh reducing environments to milder acid-catalyzed decomposition.
2Productivity
If thermal decomposition of secondary ozonides is used, then reaction proceeds rapidly, but uncontrolled exothermic decomposition occurs leading to variable product mixtures
Solution Approach 1:
The organic acid acts as a mediator that controls the thermal decomposition pathway. Instead of direct uncontrolled thermal decomposition, the acid facilitates a stepwise mechanism through peroxycarboxylic acid intermediates, maintaining rapid reaction rates while ensuring consistent product formation through a controlled pathway.
Solution Approach 2:
The organic acid is introduced before thermal decomposition to pre-organize the reaction pathway. This preliminary action of acid-catalyzed activation creates a controlled decomposition route that maintains the speed advantage of thermal methods while preventing the runaway exothermic decomposition that leads to product inconsistency.
3Adaptability or versatility
If oxidative cleavage is used to quench ozonides, then carboxylic acid and ketone products are obtained, but aldehyde products cannot be produced
Solution Approach 1:
The patent changes the oxidation state parameters by using organic acids at controlled concentrations and temperatures. This parameter adjustment allows the reaction to stop at the aldehyde stage rather than proceeding to full oxidation, thereby expanding the product range to include aldehydes while maintaining selectivity through controlled reaction conditions.
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 method provides a mild and economical route for the direct production of aldehydes and carboxylic acids from ozonides with high yield and purity, reducing the complexity and cost of ozonide quenching processes while avoiding over-reduction and chemical incompatibilities.
Implementation Method 1
the method comprising treating the ozonide intermediate with a Bronsted base
Implementation Method 2
subject to auto-accelerating thermal decomposition
Implementation Method 3
strong driving force of peroxide bond decomposition (highly exothermic) and unselective kinetic pathways such as radical propagation
Data Source
AI summary
The present disclosure provides improved methods of performing ozonolysis on alkenes comprising non-reductive quenching of ozonide intermediates using Bronsted bases to yield aldehyde, ketone and/or carboxylic acid products.