V-Ti-P Catalyst Preparation Using Redox-Active Organo-Titanium
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Solution Overview
Problem
Current catalysts for preparing 2,3-unsaturated carboxylic acids, such as acrylic acid, are inefficient due to water and methanol inhibition, and the preparation of Vanadium-Titanium-Phosphorus (V-Ti-P) mixed oxide catalysts is hazardous and not scalable for industrial production.
Innovation Solution
A catalyst composition comprising a mixed oxide of vanadium, titanium, and phosphorus, where the titanium component is derived from a water-soluble, redox-active organo-titanium compound, is prepared using a method involving an aqueous solution, heat-treatment, water removal, and calcination, enabling safer and more scalable production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If titanium chloride hydrolysis is used to incorporate titanium into V-Ti-P catalysts, then the catalyst can be prepared, but large quantities of hydrochloric acid fumes are generated making the process dangerous and not amenable to scale-up
Solution Approach 1:
The patent changes the chemical parameters of the titanium source from titanium chloride (TiCl4) to titanium sulfate (Ti(SO4)2) or titanium oxysulfate (TiO(SO4)). This parameter change eliminates the generation of hydrochloric acid fumes during hydrolysis, as these alternative titanium sources produce sulfuric acid or neutral products instead. The new titanium sources maintain the required redox activity and catalytic function while resolving the harmful emissions issue, enabling safe industrial scale-up.
2Productivity
If conventional V-Ti-P catalysts are used, then catalyst preparation is possible, but water and methanol inhibit the condensation reaction reducing efficiency
Solution Approach 1:
The patent employs a water-soluble organo-titanium compound that acts as a temporary precursor during catalyst synthesis. This precursor is designed to be consumed during the calcination process, transforming into the active titanium oxide species in the final catalyst. The water solubility allows complete dissolution and homogeneous distribution in the aqueous synthesis medium, ensuring uniform catalyst composition that is tolerant to water and methanol in the reaction feedstock, thereby maintaining high productivity despite the presence of these inhibitory substances.
3Quantity of substance
If industrial grade aqueous formaldehyde (55 wt%) is used as a starting material, then it is economical, but water content inhibits the condensation reaction with conventional catalysts
Solution Approach 1:
The patent creates a composite catalyst system combining vanadium oxide, titanium oxide (from the water-soluble organo-titanium compound), and phosphorus oxide in specific ratios. This composite material synergistically enhances water tolerance through the titanium component, which stabilizes the catalyst structure and maintains active sites even in the presence of water. The composite nature allows the catalyst to effectively process industrial grade aqueous formaldehyde (55 wt%) while maintaining high conversion efficiency, making the process both economical and effective.
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 resulting catalysts exhibit higher surface area and acidity, leading to increased activity and selectivity for acrylic acid formation, even with aqueous formaldehyde sources, and avoid the hazards associated with traditional titanium chloride hydrolysis.
Implementation Method 1
heat-treating the mixture
Implementation Method 2
calcining the solid residue at an elevated temperature in the presence of air
Implementation Method 3
removing water from the heat-treated mixture
Implementation Method 4
contacting a formaldehyde source with a carboxylic acid in the presence of a condensation catalyst under vapor-phase condensation conditions
Implementation Method 5
redox-active organo-titanium compound
Implementation Method 6
calcining the solid residue at an elevated temperature in the presence of air
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.