Nitroalkane Recovery via Aqueous Phase Recycle

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional nitration processes for hydrocarbons are energy-intensive and costly due to the need to process large aqueous and oil phases, with existing methods failing to provide economical and energy-efficient methods for nitroalkane synthesis.

Innovation Solution

A process involving the recycling of the aqueous phase back to the nitration reactor, where the product stream is quenched to separate into oil, gas, and aqueous phases, with the aqueous phase divided and recycled, allowing for the absorption of components and recovery of nitroalkanes from both phases, thereby reducing energy consumption and capital expenditures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional vapor phase nitration schemes are used with rapid quenching and separation, then nitroalkane production is achieved, but large energy expenditures are required for processing both aqueous and oil phases

Engineering Contradiction:

Improvenitroalkane production efficiencyVSAvoidenergy expenditure for phase processing

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent extracts and recycles the aqueous phase containing nitric acid from the reaction mixture back to the nitration reactor, separating it from the oil phase that requires distillation. This extraction of the valuable nitric acid component for reuse reduces the energy required for processing the entire aqueous phase through distillation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent recovers nitric acid from the aqueous phase by recycling it back to the reactor, while discarding only the spent oil phase for distillation. This selective recovery and disposal strategy reduces overall energy consumption compared to processing all phases equally.

Inventive Principle:

Principle #34Discarding and recovering

2Adaptability or versatility

If new high pressure phase nitration processes use lower strength nitric acid, then reaction conditions are improved, but a larger aqueous phase is produced requiring more energy-consuming processing

Engineering Contradiction:

Improvenitration process flexibilityVSAvoidenergy consumption for aqueous phase processing

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The patent extracts the aqueous phase containing dilute nitric acid from the reaction mixture and recycles it back to the reactor. This allows the use of lower strength nitric acid for improved reaction conditions while avoiding the energy penalty of processing large volumes of aqueous phase, since the nitric acid is reused.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent maintains continuous recycling of the aqueous phase containing nitric acid back to the reactor, ensuring that the nitric acid remains in continuous use rather than being discarded and requiring replenishment. This continuous action reduces energy consumption while maintaining process flexibility.

Inventive Principle:

Principle #20Continuity of useful action

3Loss of substance

If both aqueous phase and oil phase are processed simultaneously by distillation, then complete nitroalkane recovery is achieved, but very energy-consuming operations are required

Engineering Contradiction:

Improvenitroalkane recovery completenessVSAvoidenergy consumption for simultaneous phase processing

Core Design Contradiction:

Loss of substanceVSUse of energy by moving object

Solution Approach 1:

The patent segments the processing of the two phases: the aqueous phase is separated and recycled to the reactor, while only the oil phase undergoes distillation for nitroalkane recovery. This segmentation avoids the energy-intensive simultaneous processing of both phases while ensuring complete nitroalkane recovery from the oil phase.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent recovers nitroalkanes from the oil phase through distillation while discarding the aqueous phase for recycling back to the reactor. This selective recovery approach reduces energy consumption compared to processing both phases through distillation, as the aqueous phase is reused rather than processed.

Inventive Principle:

Principle #34Discarding and recovering

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 enables the recycling of a majority of the aqueous phase as nitric acid diluent, minimizing energy and capital requirements, while maintaining reactor performance by maintaining low concentrations of nitropropanes, thus achieving efficient nitroalkane recovery with reduced energy and capital costs.

Implementation Method 1

quenching the product stream to separate the product stream into at least an oil phase, a gas phase, and an aqueous phase

Methodology Applied

Scientific EffectPhase separation: Phase Change

Implementation Method 2

absorbing oil-soluble and water-soluble components from the gas phase into the oil phase and the second aqueous stream, respectively

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP2490997B1Process for nitroalkane recovery by aqueous phase recycle to nitration reactor

Publication Date: 2019.03.20 ANGUS CHEM CO

Figure 1

AI summary

Disclosed are a process and an apparatus for synthesizing nitroalkanes by reaction of a hydrocarbon feedstock with aqueous nitric acid. Energy and capital costs may be reduced by recycling a majority of the aqueous phase back to the reactor.