Liquid-Phase Alcohol Oxidation for Selective Unsaturated Aldehydes
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Solution Overview
Problem
Existing methods for preparing alpha, beta unsaturated aldehydes, such as prenal, require high temperatures and pressures, expensive equipment, and result in low space-time-yields and specific activities, with potential over-oxidation to acids, and involve the use of toxic or expensive reagents.
Innovation Solution
A process using platinum as a catalytically active metal on a support, in a liquid phase with 0.1 to 25% water and 25 to 99.9% alcohol, with oxygen as an oxidant at 20 to 100°C and 1 bar pressure, minimizing solvent use and optimizing conditions for high yield and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas phase oxidation is used with silver catalyst, then conversion rates and selectivity can be improved, but high temperatures (360°C) and expensive equipment are required
Solution Approach 1:
The patent changes the phase parameter from gas phase to liquid phase oxidation, and changes the catalyst material from silver to platinum. This parameter change allows the reaction to proceed at much lower temperatures (20-100°C) while maintaining high selectivity for the aldehyde product, resolving the contradiction between selectivity and temperature requirements
Solution Approach 2:
The patent uses platinum as an alternative catalyst that copies the function of silver catalyst but operates under milder conditions. The platinum catalyst achieves similar or better selectivity without requiring high temperature equipment, effectively replacing the expensive high-temperature system with a more economical low-temperature system
2Speed
If gas phase oxidation at high temperature is used, then adequate reactivity is ensured, but decomposition reactions of sensitive reactants and products occur
Solution Approach 1:
The patent changes the temperature parameter from 360°C to 20-100°C and changes from gas phase to liquid phase oxidation. This parameter change maintains adequate reaction rate through the use of platinum catalyst while preventing decomposition of sensitive reactants and products, resolving the contradiction between reaction speed and product stability
3Temperature
If liquid phase oxidation with organic solvents is used, then milder conditions are achieved, but space-time-yields are low
Solution Approach 1:
The patent changes the solvent parameter from conventional organic solvents to a water-alcohol mixture with specific composition (0.1 to less than 25 weight-% water). This parameter change enables the reaction to proceed at mild temperatures while achieving high space-time-yields (up to 14.67 g/l/h), resolving the contradiction between mild conditions and productivity
Solution Approach 2:
The patent uses a composite liquid phase system combining water and alcohol in specific ratios, which combines the advantages of both solvents: the mild conditions provided by organic solvents and the high productivity enabled by water-soluble reaction conditions. This composite solvent system resolves the contradiction between mild conditions and space-time-yield
4Manufacturing precision
If high water content is used in liquid phase, then selectivity is improved, but reaction rate decreases
Solution Approach 1:
The patent optimizes the water content parameter to a specific range (0.1 to less than 25 weight-%), which is lower than conventional aqueous systems. This parameter change maintains high selectivity while preventing the reaction rate decrease that occurs at high water concentrations, resolving the contradiction between selectivity and reaction rate
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
Achieves high yield and selectivity with reduced catalyst amounts, allowing easy isolation and high concentration of aldehydes, and significantly improves space-time-yields and specific activities.
Implementation Method 1
in the presence of a catalyst, wherein the catalyst comprises as catalytically active metal platinum
Implementation Method 2
by oxidation of alcohols of general formula (II) wherein the oxidant is oxygen
Data Source
Figure 1
Figure 2
AI summary
Process for the preparation of alpha, beta unsaturated aldehydes by oxidation of alcohols in the presence of a liquid phase wherein the liquid phase contains 0.1 to less than 25weight-% water and wherein the liquid phase contains at least 25 weight-% of alcohol(s) of general formula (II) and alpha, beta unsaturated aldehyde(s) of general formula (I) and wherein the oxidant is oxygen and/or hydrogen peroxide.