Fractional Distillation of Fatty Acid Esters for Polyol Production

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Solution Overview

Problem

Conventional methods for purifying fatty acid alkyl esters, such as fractional crystallization, are inefficient and require additional solvents, leading to partial fractionation and high costs due to the need for solvent recovery, especially when dealing with mixtures of saturated and unsaturated fatty acids.

Innovation Solution

The use of fractional distillation to separate saturated and unsaturated fatty acid alkyl esters, reducing viscosity and eliminating the need for additional solvents in oxidative ozonolysis, allowing for the production of ozone esters with improved fluidity and performance in polyurethane and lubricant applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fractional crystallization is used to purify fatty acid alkyl esters, then saturated fatty acids can be partially removed, but the process requires additional solvents, results in only partial fractionation, and requires costly solvent recovery

Engineering Contradiction:
Improvefractionation efficiencyVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the physical state parameter of the fatty acid alkyl esters from solid/liquid mixture to vapor phase, enabling separation by volatility differences rather than solubility differences. This transforms the crystallization process into a distillation process, eliminating the need for solvents and achieving more complete fractionation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical filtration step (required in crystallization to separate solid crystals from liquid) with a vapor-phase distillation process. The separation is achieved through phase change and volatility differences, eliminating the need for mechanical separation equipment and solvent recovery systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If oxidative ozonolysis is performed on high viscosity fatty acid mixtures, then the reaction can proceed, but the high viscosity reduces mixing efficiency and reaction rate

Engineering Contradiction:
Improvereaction rateVSAvoidviscosity
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The patent performs fractional distillation before oxidative ozonolysis to remove saturated fatty acid alkyl esters and reduce mixture viscosity. This preliminary action creates optimal reaction conditions by ensuring the fatty acid mixture has sufficiently low viscosity for efficient mixing and gas-liquid contact during ozonolysis.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If saturated fatty acids are not removed before oxidative ozonolysis, then all fatty acids remain in the mixture, but the saturated fatty acids do not react with ozone and reduce the efficiency of the reaction

Engineering Contradiction:
Improvereactive unsaturated fatty acid concentrationVSAvoidreaction efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent extracts and removes saturated fatty acid alkyl esters from the mixture through fractional distillation before oxidative ozonolysis. This extraction step concentrates the unsaturated fatty acids that react with ozone, eliminating the dilution effect of non-reactive saturated fatty acids and improving reaction efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Fractional distillation effectively reduces saturated fatty acid content in esters, enhancing the viscosity and performance of resulting ester polyols and lubricant base stocks, making the process more economical and efficient compared to traditional crystallization methods.

Implementation Method 1

The intermediate fatty acid alkyl esters or ozone esters have a reduced saturated fatty acid content due to pre-treatment steps that partially removes saturated fatty acids or saturates by the process of fractional distillation

Methodology Applied
Scientific EffectFractional distillation: Distillation

Implementation Method 2

fatty acids may be subjected to oxidative ozonolysis which involves an initial reaction with ozone to form intermediate ozonides followed by the oxidation of such intermediates with oxygen and a catalyst

Methodology Applied
Scientific EffectOxidative ozonolysis: Oxidation

Implementation Method 3

the oxidative ozonolysis process cleaves all double bonds in unsaturated fatty acids and introduces carboxylic acid functionality at all original double-bonded carbon atoms present in unsaturated fatty acids

Methodology Applied
Scientific EffectOzone reaction: Ozone

Data Source

PatentEP2820112B1Method for the production of polyols and uses thereof
Publication Date: 2017.05.17 PETROLIAM NASIONAL BHD
  • EP2820112B1 patent drawingFigure 1
  • EP2820112B1 patent drawingFigure 2
  • EP2820112B1 patent drawingFigure 3

AI summary

The present invention provides a pretreatment method to reduce saturated fatty acids of fatty acids used as feedstock when preparing ester polyols. The range of feedstock includes non-fractionated to fully fractionated feedstock. Performing some fractionation by distillation of the fatty acids derived from feedstock eliminates the need to fractionate the various ozone esters from each other before esterification. Further, the approach of the present invention is more economical and efficient than the conventional method of fractionation by crystallization.