Rotating Supergravity Reactor for Oxalate Production
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Solution Overview
Problem
The existing methods for producing oxalate through the CO gas phase method suffer from low utilization efficiency and selectivity of nitrogen oxides or nitrous acid esters, leading to high energy consumption, material wastage, and environmental pollution due to side reactions and inefficient gas management.
Innovation Solution
A process involving the reaction of nitrite salts with water and inorganic acids to produce NO, followed by oxidative esterification with alcohols and oxygen, and subsequent coupling with CO in the presence of a Pd-containing catalyst, using rotating supergravity reactors to enhance mass transfer and reduce side reactions, thereby improving NO selectivity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the CO gas phase method is used to produce oxalate, then the production cost is reduced and energy consumption is lowered, but the utilization efficiency and selectivity of nitrogen oxides are poor leading to material wastage and environmental pollution
Solution Approach 1:
The patent implements a recovery system where unreacted nitrogen oxides (NOx) and inert gases are separated and recycled back into the reaction system. The effluent from the reactor is passed through a condensation section where oxalate is condensed, and the remaining gas phase containing NOx is recycled to the reaction zone, preventing material loss and environmental pollution while maintaining continuous production.
Solution Approach 2:
The patent optimizes reaction parameters including temperature (80-150°C), pressure (0.5-2.0 MPa), and the ratio of CO to alkyl nitrite (1:1 to 10:1) to maximize oxalate production efficiency and nitrogen oxides utilization. By controlling these parameters, the system achieves high selectivity while minimizing side reactions and material waste.
2Reliability
If nitrogen oxides are continuously supplemented to maintain stable catalytic reaction, then the reaction stability is improved, but the nonreactive gases (N2, Ar, He) accumulate and adversely affect or stop the reaction
Solution Approach 1:
The patent employs a separation system that extracts and removes inert gases from the reaction effluent. The effluent is condensed at temperatures below the dew point of oxalate but above the condensation temperatures of inert gases, allowing oxalate to be condensed and collected while inert gases remain in the gas phase and are either recycled or discharged in controlled amounts, preventing their harmful accumulation.
Solution Approach 2:
The patent implements a feedback mechanism where the composition of the effluent gas is continuously monitored and the recycling rate is adjusted accordingly. When inert gas accumulation is detected, the system increases the discharge rate of inert gases while maintaining the recycling of nitrogen oxides, ensuring reaction stability without allowing harmful gas buildup.
3Productivity
If the liquid phase method is used for oxalate synthesis, then the reaction can proceed, but the equipment corrosion and catalyst run-off increase
Solution Approach 1:
The patent utilizes phase transition by conducting the catalytic reaction in the gas phase where reactants are introduced as gases and the reaction occurs without liquid phase contact with equipment. The product oxalate is then condensed from the gas phase effluent through cooling, achieving high productivity while eliminating equipment corrosion and catalyst run-off associated with liquid phase methods.
4Productivity
If the CO coupling gas phase method is used, then the production advantage is maximized, but side reactions occur consuming more NO and requiring incessant supplementation
Solution Approach 1:
The patent recycles unreacted nitrogen oxides from the effluent gas back to the reaction system, converting what would be waste into a valuable reactant. This recovery process eliminates the need for incessant NO supplementation while maintaining high productivity, as the recycled NO continues to participate in the coupling reaction.
Solution Approach 2:
The patent establishes a continuous reaction and recycling system where nitrogen oxides that do not react in one pass are not discarded but continuously fed back into the reactor. This continuous utilization of NO ensures that the useful action of nitrogen oxides in promoting the coupling reaction is maintained without interruption or excessive supplementation.
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 high selectivity of NO (>98%) and efficient production of oxalate with reduced energy consumption and minimal environmental impact by minimizing side reactions and inert gas losses, resulting in improved operational conditions and cost-effectiveness.
Implementation Method 1
The present invention utilizes a rotating supergravity reactor to carry out the coupling reaction of CO and alkyl nitrite
Implementation Method 2
the effluent IV of C1-C4 alkyl nitrites and a CO gas stream enter a coupling reactor where they are contacted with a Pd-containing catalyst and reacted to produce an effluent V of oxalate
Implementation Method 3
the effluent II of NO and C1-C4 alkanol and oxygen enter a reactor II to be subjected to the oxidative esterification reaction to produce an effluent III comprising C1-C4 alkyl nitrites
Data Source
AI summary
A process of producing oxalate by CO gas phase method includes the following steps: a) introducing nitrite salt, water and an inorganic acid first into a reactor I to produce a NO containing effluent I; and separating the resultant effluent to obtain the effluent II of NO; b) introducing the effluent II of NO, a C1-C4 alkanol and oxygen into a reactor II to be subjected to the reaction, and separating the resultant effluent to obtain the effluent IV of C1-C4 alkyl nitrites; c) introducing the effluent IV of C1-C4 alkyl nitrites and a CO gas stream into a coupling reactor where they are reacted to produce a NO containing effluent VI. The reactor I and/or the reactor II are preferably rotating supergravity reactors. Therefore, the process is applicable to the industrial production of oxalate by CO gas phase method.