Multi-Stage Oxidation of Alkanes to Unsaturated Acids
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Solution Overview
Problem
Current methods for producing unsaturated carboxylic acids and nitriles from alkanes and alkenes, such as propane and propene, face limitations in yield and selectivity, with existing single-step vapor phase catalytic oxidation processes not fully optimizing the conversion of alkanes to their corresponding unsaturated products.
Innovation Solution
A multi-stage vapor phase oxidation process with at least two reaction zones in series, using a supported mixed metal oxide catalyst with a specific empirical formula (MoaVbNcXdOe) on a three-dimensional ceramic support, where intermediate effluents are separated and recycled with supplemental oxygen, enhancing the overall yield and selectivity of unsaturated carboxylic acids or nitriles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-step vapor phase catalytic oxidation process is used to convert alkanes to unsaturated carboxylic acids, then the process simplicity is maintained, but the yield and selectivity are insufficient
Solution Approach 1:
The oxidation process is divided into multiple reaction zones arranged in series, where each zone performs a specific function. The first zone performs initial oxidation, intermediate zones separate and recycle products, and subsequent zones complete the conversion. This segmentation enables higher overall yield while maintaining manageable process complexity through modular design.
Solution Approach 2:
The process implements continuous recycling of intermediate products between reaction zones, ensuring that unreacted alkanes and formed products continuously circulate through the system. This continuous action maximizes conversion efficiency and maintains high yield without requiring complex batch processing.
2Productivity
If intermediate effluent streams are separated and recycled with supplemental oxygen, then the overall yield exceeds the cumulative sum of individual zones, but the device complexity increases
Solution Approach 1:
Multiple reaction zones are merged into a single integrated system where intermediate streams are recycled between zones. The supplemental oxygen is staged and added at specific points in the series arrangement, combining the functions of multiple independent reactors into one coordinated process that achieves synergistic yield improvement.
Solution Approach 2:
The process incorporates feedback loops where intermediate effluent streams are separated, partially condensed, and recycled back to previous or subsequent reaction zones. This feedback mechanism ensures continuous optimization of reactant conversion and product formation, achieving overall yield greater than the sum of individual zone yields.
3Manufacturing precision
If less than full stoichiometrically required amount of oxygen is fed to the first reaction zone, then selectivity is improved, but the conversion rate decreases
Solution Approach 1:
The oxygen addition is segmented across multiple reaction zones rather than providing full stoichiometric amount at the first zone. Each zone receives controlled oxygen amounts optimized for its specific function, allowing high selectivity in early zones and high conversion in later zones, achieving overall optimization of both selectivity and rate.
Solution Approach 2:
The process performs preliminary oxidation with limited oxygen in the first reaction zone to form intermediate products with high selectivity. Unreacted alkanes and intermediate products are then carried to subsequent zones where additional oxygen is supplied to complete the conversion. This preliminary action strategy optimizes both selectivity and overall conversion 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
This process achieves unexpected increases in selectivity and yield, exceeding the cumulative sum of individual reaction zone yields, by optimizing the conversion of C3 to C5 alkanes and alkenes to their corresponding unsaturated products, such as acrylic acid and acrylonitrile.
Implementation Method 1
single-step vapor phase catalytic oxidation of alkanes, alkenes, and mixtures thereof to their corresponding unsaturated carboxylic acids and unsaturated nitriles
Implementation Method 2
vapor phase catalytic oxidation reaction in the presence of a suitable mixed metal oxide catalyst, to produce the corresponding unsaturated carboxylic acid
Data Source
AI summary
An improved process for the production of unsaturated carboxylic acids and unsaturated nitriles from their corresponding C3 to C5 alkanes, or mixtures of C3 to C5 alkanes and alkenes, that involves oxidation in the presence of a supported Mo—V-based mixed metal oxide catalyst in a multi-stage reaction system which employs both separation of the oxidation product from one or more intermediate effluent streams, as well as feeding additional oxygen to reaction zones subsequent to the first reaction zone.