Ethoxyquin Purification via Vacuum Distillation

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Solution Overview

Problem

Current methods fail to achieve high-purity ethoxyquin with p-phenitidine content below 100 ppm, which is essential for toxicological safety, as existing purification processes cannot effectively remove this impurity from ethoxyquin.

Innovation Solution

A distillation process using a dividing wall column or thermally coupled columns, which allows for a single-stage distillation to achieve ethoxyquin with p-phenitidine levels below 100 ppm, preferably less than 50 ppm, and most preferably less than 5 ppm, by optimizing parameters such as temperature, pressure, and residence time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional purification methods (adsorption, acid washing, chromatography, crystallization) are used, then the process complexity increases and multiple steps are required, but the p-phenitidine removal efficiency remains insufficient (cannot achieve less than 1000 ppm)

Engineering Contradiction:
Improvep-phenitidine removal efficiencyVSAvoidpurification process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by utilizing the significant difference in volatility between ethoxyquin (boiling point 123-125°C at 2.67 hPa) and p-phenitidine (boiling point 254°C). Through vacuum distillation with controlled temperature and pressure parameters, the process achieves efficient separation of the low-boiling ethoxyquin from the high-boiling p-phenitidine impurity, reaching purities below 100 ppm without requiring complex multi-step purification sequences

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention extracts the harmful p-phenitidine component from the ethoxyquin mixture through distillation. By operating under vacuum conditions, the ethoxyquin is vaporized and condensed separately from the non-volatile or low-volatility p-phenitidine, effectively taking out the impurity and achieving the desired purification level in a single operation

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If distillation is used for fine purification of ethoxyquin, then the process is simplified to a single step, but conventional wisdom suggests distillation is not suitable for fine purification (only for coarse purification)

Engineering Contradiction:
Improvepurification process simplicityVSAvoidpurification effectiveness
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent transforms distillation from a coarse purification method into a fine purification method by changing the operating parameters. Under vacuum conditions (2.67 hPa) and controlled temperatures, the distillation process achieves high precision separation, proving that distillation can effectively remove trace impurities (below 100 ppm) when appropriate parameters are applied, contradicting the conventional view that distillation is only suitable for coarse purification

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If multiple purification steps are implemented to achieve high purity, then the p-phenitidine content decreases, but the production time and cost increase

Engineering Contradiction:
Improveethoxyquin purityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention segments the purification task into a single optimized distillation operation rather than multiple sequential steps. By carefully controlling the distillation parameters (vacuum level, temperature profile, reflux ratio), the process achieves complete purification in one step, eliminating the need for sequential purification operations and thereby maintaining high productivity while achieving the required purity level

Inventive Principle:
Principle #1Segmentation

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

The process effectively reduces p-phenitidine content in ethoxyquin to extremely low levels, making it suitable for use as an antioxidant in food and feed, while being scalable and cost-effective.

Implementation Method 1

Method for purifying ethoxyquin by distillation

Methodology Applied
Scientific EffectDistillation: Distillation

Implementation Method 2

Ethoxyquin has a melting point below zero °C and a boiling point of approximately 123 to 125 °C at 2.67 hPa

Methodology Applied
Scientific EffectVacuum distillation: Vacuum Distillation

Data Source

PatentEP3478660B1Method for purifying ethoxyquin
Publication Date: 2021.08.11 BASF SE
  • EP3478660B1 patent drawingFigure 1
  • EP3478660B1 patent drawingFigure 2
  • EP3478660B1 patent drawingFigure 3

AI summary

The present invention relates to a method for the purification of ethoxyquin by distillation, to high-purity ethoxyquin that can be obtained by distillative purification and to the use thereof in particular as an additive in foodstuffs and animal feed.