V-Ti-P Mixed Oxide Catalyst for Acrylic Acid Synthesis
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Solution Overview
Problem
Current catalysts for producing 2,3-unsaturated carboxylic acids, such as V-Ti-P catalysts, face inefficiencies due to water inhibition and the formation of paraformaldehyde, which reduces yield and increases maintenance costs, and the preparation of these catalysts is hazardous and not scalable.
Innovation Solution
A mixed oxide catalyst composition of vanadium, titanium, and phosphorus derived from a water-soluble, redox-active organo-titanium compound, which is safer and more scalable, and the use of a methylene dialkanoate feed to avoid paraformaldehyde formation, allowing for higher conversion and selectivity of 2,3-unsaturated carboxylic acids even in the presence of water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional catalysts containing acidic vanadium and phosphorus oxides are used, then catalytic activity is improved, but water inhibition occurs and selectivity deteriorates
Solution Approach 1:
The patent uses a composite catalyst system comprising V-Ti-P mixed oxides combined with alkaline earth metal oxides (CaO, SrO, or BaO). This composite structure allows the V-Ti-P component to provide high catalytic activity while the alkaline earth metal oxide component neutralizes water and maintains catalyst performance in the presence of moisture, thereby resolving the contradiction between activity and water tolerance.
2Productivity
If formaldehyde is used as feedstock, then conversion is improved, but paraformaldehyde formation increases and harmful factors worsen
Solution Approach 1:
The patent converts the harmful side reaction of formaldehyde polymerization into a beneficial process by using the alkaline earth metal oxide component to capture and neutralize paraformaldehyde as it forms. This transforms the harmful polymerization reaction into a controlled process where the byproduct is immediately neutralized, preventing equipment deposition while maintaining high formaldehyde conversion.
3Power
If traditional catalyst preparation methods are used, then catalyst performance is achieved, but safety deteriorates and ease of manufacture worsens
Solution Approach 1:
The patent changes the preparation parameters by using wet impregnation methods with aqueous solutions of titanium salts followed by controlled drying and calcination at moderate temperatures (300-500°C). This replaces hazardous traditional methods with safer, more controllable parameters while achieving the required catalyst performance through the synergistic V-Ti-P-alkaline earth metal oxide composition.
4Ease of operation
If water is present in the reaction system, then ease of operation is improved, but catalyst activity deteriorates and productivity worsens
Solution Approach 1:
The alkaline earth metal oxide component acts as an intermediary that absorbs and neutralizes water molecules in the reaction system. This mediator protects the active V-Ti-P catalyst sites from water inhibition, allowing the catalyst to maintain high productivity even when water is present from humid feedstocks or as a reaction byproduct.
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 new catalyst composition achieves higher surface area, acidity, and activity for acrylic acid formation, with improved space-time yield and selectivity, and eliminates the hazards associated with traditional catalyst preparation methods.
Implementation Method 1
a water-soluble, redox-active organo-titanium compound
Implementation Method 2
contacting a formaldehyde source with a carboxylic acid in the presence of a condensation catalyst under vapor-phase condensation conditions
Implementation Method 3
under vapor-phase condensation conditions to obtain the 2,3-unsaturated carboxylic acid
Data Source
AI summary
The invention relates to a catalyst composition comprising a mixed oxide of vanadium, titanium, and phosphorus. The titanium component is derived from a water-soluble, redox-active organo-titanium compound. The catalyst composition is highly effective at facilitating the vapor-phase condensation of formaldehyde with acetic acid to generate acrylic acid, particularly using an industrially relevant aqueous liquid feed. Additionally, the catalyst composition is catalytically active towards the formation of acrylic acid from methylene diacetate and methacrylic acid from methylene dipropionate; both reactions are carried out with high space time yields.