Rotating High-Gravity Reactor for Alkyl Nitrite Selectivity
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Solution Overview
Problem
The existing processes for producing C1-C4 alkyl nitrite in the synthesis of oxalate via CO coupling suffer from low selectivity and significant side reactions, particularly the production of nitric acid, leading to increased energy consumption and apparatus erosion.
Innovation Solution
A process involving a two-reactor system where nitrogen oxide and oxygen are first reacted with an aluminosilicate catalyst in a fixed bed reactor to produce NO2 and unreacted NO, then mixed with C1-C4 alkanol in a rotating high-gravity reactor to enhance selectivity and prevent side reactions, utilizing a molar ratio of NO to oxygen between 4-25:1 and operating conditions optimized for high temperature and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the gaseous phase method is used for synthesizing oxalate by CO coupling, then the production cost is reduced and energy consumption is lowered, but side reactions occur leading to production of nitric acid which increases energy consumption and erodes apparatus
Solution Approach 1:
The reaction process is divided into two distinct stages: first, oxidation of NO to NO2 in a fixed bed reactor; second, carbonylation of NO2 with CO in a rotating high-gravity reactor. This segmentation allows optimization of each stage independently, preventing side reactions while maintaining energy efficiency.
Solution Approach 2:
The invention changes the chemical parameters by using NO2 instead of NO as the reactant in the carbonylation step, and controls the molar ratio of NO to oxygen in the range of 4-25:1. These parameter changes shift the reaction pathway to avoid side reactions and reduce energy consumption.
2Temperature
If the liquid phase method is used for synthesizing oxalate by CO coupling, then the reaction can proceed at lower temperatures, but the apparatus is easily corroded and the catalyst is easy to lose
Solution Approach 1:
The invention uses a gas-phase reaction environment with controlled atmosphere, avoiding the liquid phase that causes corrosion. The gaseous reactants (NO, O2, CO) and gaseous products move through a corrosion-resistant reactor system, eliminating the apparatus corrosion problem while maintaining lower temperature operation.
3Ease of manufacture
If conventional esterification method is used for producing oxalate, then the process is simple, but the production process cost is high and energy consumption is high and pollution is heavy
Solution Approach 1:
The invention uses strong oxidation of NO to NO2 as the first step, followed by carbonylation. This accelerated oxidation pathway is more efficient than conventional esterification, reducing energy consumption and pollution while maintaining process simplicity through the two-step reaction sequence.
4Productivity
If the molar ratio of NO to oxygen is not optimized, then the reaction can proceed, but the selectivity of alkyl nitrite is low and side reactions increase
Solution Approach 1:
The invention optimizes the molar ratio of NO to oxygen to the range of 4-25:1, which is a critical parameter change. This optimization ensures that NO is the limiting reagent, maximizing the selectivity for alkyl nitrite production while maintaining good reaction rate through the two-step process.
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 approach achieves selectivity of C1-C4 alkyl nitrite greater than 99% by minimizing side reactions and optimizing gas-liquid mass transfer in the rotating high-gravity reactor, reducing energy consumption and apparatus erosion.
Implementation Method 1
contacting with an aluminosilicate catalyst, and reacting to produce an effluent I containing NO2 and unreacted NO
Implementation Method 2
reacting to produce an effluent II containing C1-C4 alkyl nitrite, wherein Reactor II is a rotating high-gravity reactor
Data Source
AI summary
A process of producing C1-C4 alkyl nitrite, comprising the following steps: a) firstly feeding nitrogen oxide and oxygen into Reactor I, contacting with an aluminosilicate catalyst, and reacting to produce an effluent I containing NO2 and unreacted NO; b) feeding the effluent I and C1-C4 alkanol into Reactor II, and reacting to produce an effluent II containing C1-C4 alkyl nitrite; and c) separating the effluent II containing C1-C4 alkyl nitrite to obtain C1-C4 alkyl nitrite; wherein reactor I is a fixed bed reactor, and Reactor II is a rotating high-gravity reactor; said nitrogen oxide in step a) is NO, or a mixed gas containing NO and one or more of N2O3 and NO2, wherein the molar number of NO is greater than that of NO2, if any; and the molar ratio of NO in nitrogen oxide to oxygen is 4-25:1.