Phenoxyethanol Manufacturing Without Autoclave Purity Bottlenecks

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Solution Overview

Problem

Existing methods for producing phenoxyethanol are inefficient in removing phenol impurities, require high temperatures or specialized equipment, and result in products unsuitable for pharmaceutical applications due to high phenol content.

Innovation Solution

A method involving the reaction of phenolate with monohalohydrin at a temperature below the boiling point of the mixture without a catalyst, followed by extraction and fractional distillation to produce high-purity phenoxyethanol suitable for pharmaceutical use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phenol and ethylene oxide are reacted in an alkaline environment to produce phenoxyethanol, then the product shows moderate antibacterial and antifungal properties suitable for cosmetics and medicinal products, but the presence of gaseous ethylene oxide requires the reaction to be run in an autoclave and tight process control is needed to manage impurities

Engineering Contradiction:
Improveproduct purity for pharmaceutical useVSAvoidautoclave equipment and process control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the reaction parameters by using phenolate salt and monochlorohydrin instead of phenol and ethylene oxide, allowing the reaction to proceed at lower temperatures (60-80°C) without requiring autoclave equipment. This parameter change eliminates the need for specialized high-pressure equipment while maintaining product quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces expensive and complex autoclave equipment with simple, inexpensive reaction vessels that can operate at atmospheric pressure. The process uses readily available materials (phenolate salt, monochlorohydrin, and common solvents) instead of requiring specialized pharmaceutical-grade equipment

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If ethylene oxide is added to increase selectivity toward mono-derivative, then the expected product selectivity improves, but the process requires tight control of reaction yield or impurities content which reduces economic efficiency

Engineering Contradiction:
Improveselectivity toward mono-derivativeVSAvoideconomic efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the reactant parameters by using phenolate salt (rather than phenol) and monochlorohydrin (rather than ethylene oxide), which inherently provides better selectivity for the mono-derivative product. This eliminates the need for tight process control and complex monitoring systems, improving economic efficiency

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If phenol and ethylene carbonate are reacted in the presence of alkaline catalysts using a heterogeneous catalyst like Na-Mordenite, then catalyst separation becomes easier, but the process must be run at high temperatures of 210°C to 250°C which increases energy consumption

Engineering Contradiction:
Improvecatalyst separationVSAvoidenergy consumption for high temperature
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The invention changes the temperature parameter by using phenolate salt and monochlorohydrin as reactants, which allows the reaction to proceed at mild temperatures (60-80°C) without requiring high-temperature conditions. This eliminates the energy-intensive heating requirement while maintaining ease of catalyst separation through simple filtration

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If conventional distillation is used to purify phenoxyethanol, then the purification process is simple, but unreacted phenol sublimes under distillation conditions and passes into the distillate making it ineffective for removal

Engineering Contradiction:
Improvepurification simplicityVSAvoidphenol removal efficiency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the reaction parameters to use phenolate salt and monochlorohydrin, which produces significantly less unreacted phenol in the final product. This parameter change makes conventional distillation effective for phenol removal, as the reduced phenol content prevents sublimation issues and achieves the required pharmaceutical purity

Inventive Principle:
Principle #35Parameter changes

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 method achieves a yield of at least 75% with phenol and unspecified impurities below 0.10% w/w, meeting pharmaceutical standards and eliminating the need for specialized equipment.

Implementation Method 1

reacting phenolate with a monohalohydrin being 2-haloethanol at a reaction temperature that is less than or equal to the boiling point of the reaction mixture

Methodology Applied
Scientific EffectNucleophilic substitution: Chemical Bonding

Implementation Method 2

extracting the products from the cooled reaction mixture

Methodology Applied
Scientific EffectLiquid-liquid extraction: Liquid-Liquid Extraction

Implementation Method 3

fractionally distilling phenoxyethanol from the washed organic phase

Methodology Applied
Scientific EffectDistillation: Distillation

Data Source

PatentEP3609860B1Methods for manufacturing phenoxyethanol
Publication Date: 2025.08.27 BAUSCH HEALTH IRELAND LTD
  • EP3609860B1 patent drawingFigure 1
  • EP3609860B1 patent drawingFigure 2
  • EP3609860B1 patent drawingFigure 3

AI summary

Methods for manufacturing phenoxyethanol from a reaction of a phenolate with a monohalohydrin. The phenolate is reacted with the monohalohydrin at a reaction temperature that is less than or equal to a boiling point of a reaction mixture to produce products that include the phenoxyethanol.