CO Gas Phase Oxalate Production via Supergravity Reactor
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Solution Overview
Problem
The existing methods for producing oxalate by CO gas phase method suffer from low utilization efficiency of nitrogen oxides or nitrous acid esters due to side reactions and material losses, leading to high operational costs and environmental pollution.
Innovation Solution
A process utilizing a supergravity rotating bed reactor with a Pd-containing catalyst and a porous filler layer, where a gas phase stream containing NO and methanol undergoes oxidative esterification to produce methyl nitrite, which is then recycled and used in a coupling reactor with CO to form dimethyl oxalate, reducing the need for NO supplementation and minimizing side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional esterification method using oxalic acid is employed, then oxalate can be produced, but production cost increases and energy consumption rises
Solution Approach 1:
The patent changes the reaction parameters from traditional esterification conditions to CO oxidative coupling conditions, operating at lower temperatures (80-150°C) and pressures (0.5-2.0 MPa), which reduces energy consumption while maintaining high productivity through continuous gas-phase processing
Solution Approach 2:
The patent extracts the core functional components (CO, alcohol, oxygen) from the traditional oxalic acid esterification process, replacing the complex multi-step esterification route with a direct one-step oxidative coupling reaction that achieves the same product formation with simpler chemistry
2Productivity
If CO liquid phase method is used for oxalate synthesis, then reaction can proceed, but equipment corrosion increases and catalyst runs off
Solution Approach 1:
The patent transitions from liquid phase to gas phase reaction system, where reactants (CO, alcohol, oxygen) and products remain in gas phase throughout the process, eliminating the corrosive effects of liquid reagents on equipment while preventing catalyst run-off through fixed-bed or fluidized-bed configurations
Solution Approach 2:
The gas phase environment creates a less reactive atmosphere compared to liquid phase, reducing the aggressiveness of the reaction medium toward equipment materials and minimizing catalyst degradation and loss
3Productivity
If nitrogen oxides are continuously supplemented to maintain catalytic reaction, then oxalate production continues, but material loss increases and environmental pollution worsens
Solution Approach 1:
The patent implements a feedback mechanism where nitrogen oxides produced in the reaction system are recycled and fed back into the reactor, creating a closed-loop system that maintains catalytic activity while minimizing nitrogen oxide loss and environmental discharge through continuous monitoring and adjustment of supplementation rates
Solution Approach 2:
The patent recovers nitrogen oxides that would otherwise be discarded as waste products or vented to atmosphere, capturing them from the effluent stream and returning them to the reaction system, thereby converting a loss into a resource that sustains continuous production
4Productivity
If side reactions occur during oxidative carbonylation, then nitrogen oxides are consumed, but utilization efficiency decreases
Solution Approach 1:
The patent optimizes local reaction conditions within the reactor, including temperature gradients, pressure distribution, and catalyst positioning, to create zones that favor the main oxidative coupling reaction while suppressing side reactions, thereby improving nitrogen oxide utilization efficiency through spatially differentiated reaction control
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 a high utilization efficiency of nitrogen oxides, greater than 98%, with reduced material losses and environmental pollution, while maintaining high selectivity and yield of oxalate production.
Implementation Method 1
a gas phase stream containing NO and methanol undergoes oxidative esterification to produce methyl nitrite, which is then recycled and used in a coupling reactor with CO to form dimethyl oxalate
Implementation Method 2
a process utilizing a supergravity rotating bed reactor with a Pd-containing catalyst and a porous filler layer
Implementation Method 3
a process utilizing a supergravity rotating bed reactor with a Pd-containing catalyst and a porous filler layer
Data Source
AI summary
The present invention relates to a process of producing oxalate by CO gas phase method for chiefly solving the technical problem of the low utilization efficiency of nitrogen oxides or nitrous acid esters in the prior art. The present invention solves the problem in a better way by using the following steps including: a gas phase stream V containing NO and methanol and oxygen enter a supergravity rotating bed reactor II and are subjected to the oxidative esterification reaction to produce an effluent VI containing methyl nitrite; a methyl nitrite effluent VII obtained from separating said effluent VI together with a CO gas II enter a coupling reactor II and is contacted with a catalyst II to react to form a dimethyl oxalate effluent VIII and a gas phase effluent IX containing NO; the resultant dimethyl oxalate effluent VIII is separated to obtain a dimethyl oxalate product I; optionally, the gas phase effluent IX containing NO is returned to the step above so as to be mixed with the gas phase stream V containing NO for being recycled. Therefore, the process is applicable to the industrial production of oxalate by CO gas phase method.