Nitric Acid Ester Production via Adiabatic Tubular Reactor
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Solution Overview
Problem
Existing processes for preparing nitric acid esters of monohydric alcohols are costly and risky due to uncontrolled decomposition and oxidative side reactions, with low yields and high monitoring requirements, especially when using continuous isothermal methods with mixed acids of sulfuric and nitric acid.
Innovation Solution
The process involves continuously reacting monohydric alcohols with a nitric acid/sulfuric acid mixed acid under adiabatic conditions, without additional reagents like urea, at elevated temperatures (10 to 80°C) in a tubular reactor, with short residence times and precise control of acid ratios to minimize by-product accumulation and oxidative risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous isothermal esterification is performed with mixed acids of sulfuric acid and nitric acid at low temperatures with short residence times, then safety against uncontrolled decomposition is improved, but manufacturing cost increases and monitoring effort increases
Solution Approach 1:
The patent changes the thermal regime from isothermal to adiabatic, allowing temperature to increase during reaction. This parameter change enables operation at higher temperatures (20-80°C) with shorter residence times (0.1-10 seconds), achieving both safety and cost-effectiveness by eliminating cooling costs and reducing reactor volume while maintaining control through rapid processing
Solution Approach 2:
The patent uses very short residence times (0.1-10 seconds) in the adiabatic reactor to rapidly pass the reaction mixture through the hazardous nitration zone. This 'rushing through' approach minimizes the time window for uncontrolled decomposition and oxidative side reactions while maintaining high yields, thereby reducing safety risks without increasing monitoring complexity
2Reliability
If continuous isothermal esterification is performed with mixed acids of sulfuric acid and nitric acid at low temperatures with short residence times, then safety against uncontrolled decomposition is improved, but productivity decreases
Solution Approach 1:
The patent changes from isothermal to adiabatic operation, allowing temperature to rise during the reaction. This enables the use of higher temperatures (20-80°C) which accelerate the reaction rate and improve yields (>99.5%) while the short residence time (0.1-10 seconds) prevents oxidative side reactions, thus achieving both safety and high productivity
3Productivity
If adiabatic reaction conditions are used with elevated temperatures, then productivity and yield are improved, but risk of uncontrolled decomposition increases
Solution Approach 1:
The patent compensates for the increased risk of adiabatic reaction by using extremely short residence times (0.1-10 seconds). This allows the reaction mixture to rapidly pass through the high-temperature zone, achieving high yields (>99.5%) while minimizing the time available for uncontrolled decomposition and oxidative side reactions to occur
4Reliability
If isothermal reaction at low temperatures is performed, then safety is improved, but reactor volume increases and start-up time increases
Solution Approach 1:
The patent changes from isothermal to adiabatic operation, allowing temperature to increase during reaction. This enables the use of smaller reactor volumes since the reaction proceeds faster at higher temperatures, and reduces start-up time as no external cooling is needed. The short residence time (0.1-10 seconds) maintains safety despite the higher temperatures
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 method achieves high yields (>99.5%) with reduced reactor volume, fast start-up, and minimal by-product accumulation, while avoiding the risks of uncontrolled reactions and oxidative decomposition, and allows for efficient phase separation and recycling of nitrating acids.
Implementation Method 1
a monohydric alcohol or a mixture of monohydric alcohols is reacted with nitric acid in the presence of sulfuric acid under adiabatic reaction conditions
Implementation Method 2
reacted with nitric acid in the presence of sulfuric acid under adiabatic reaction conditions at elevated temperatures (10 to 80°C)
Data Source
AI summary
Preparation of nitric acid esters (nitrate ester) of univalent alcohols comprises reacting the univalent alcohols or its mixture with nitric acid ester in the presence of sulfuric acid under adiabatic reaction condition.