Glycerol Deoxydehydration in Microreactors

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Solution Overview

Problem

The high viscosity of glycerol impairs its flow in micro- or mesofluidic continuous-flow reactors, requiring either high temperatures that increase production costs or dilution with solvents, which reduces conversion yield and shifts reaction balances unfavorably.

Innovation Solution

A continuous-flow process involving a reactive solution formed by mixing glycerol with a carboxylic acid, such as methanoic acid, or a triethyl orthoester, like triethyl orthoformate, which reduces viscosity and allows efficient flow through narrow channels at moderate temperatures and pressures, enabling high conversion rates of allyl compounds production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If glycerol is used in micro- or mesofluidic continuous-flow reactors, then high conversion rates and controlled selectivity are achieved, but the high viscosity of glycerol impairs its flow through narrow channels

Engineering Contradiction:
Improveconversion rateVSAvoidflow rate
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

A carboxylic acid (such as methanoic acid) or triethyl orthoester (such as triethyl orthoformate) is introduced as an intermediary substance that reacts with glycerol to form a reactive solution. This intermediary reduces the viscosity of the reaction mixture, enabling efficient flow through narrow microreactor channels while maintaining high conversion rates to allyl compounds.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical-chemical parameters of the reaction mixture by adding carboxylic acid or triethyl orthoester, which alters the viscosity and flow characteristics of the glycerol solution. This parameter change enables the reactive solution to flow satisfactorily through capillary channels at moderate temperatures and pressures.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the reaction temperature is raised to reduce glycerol viscosity, then flow rate improves, but production costs increase

Engineering Contradiction:
Improveflow rateVSAvoidproduction cost
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The carboxylic acid or triethyl orthoester acts as a viscosity-reducing intermediary that allows the reaction to proceed at moderate temperatures (200-370°C) without requiring excessive thermal energy input. This intermediary substance facilitates efficient flow through the microreactor channels at lower temperatures, reducing energy consumption and production costs.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If glycerol is diluted with water or solvent to reduce viscosity, then flow rate improves, but conversion yield decreases and reaction balance shifts unfavorably

Engineering Contradiction:
Improveflow rateVSAvoidconversion yield
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

Instead of using water or inert solvents as diluents, the invention employs carboxylic acid or triethyl orthoester as reactive intermediaries. These substances reduce viscosity and improve flow while simultaneously participating in the reaction to form allyl compounds, thereby maintaining high conversion yields and favorable reaction balances.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the composition parameters of the reaction mixture by introducing carboxylic acid or triethyl orthoester, which alters both the viscosity (improving flow) and the reaction chemistry (maintaining yield). This dual parameter change avoids the pitfalls of simple dilution with water or inert solvents.

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

This process achieves high yields of allyl compounds, up to 97%, with controlled selectivity and cost-effectiveness, avoiding the drawbacks of elevated temperatures and solvent use, while maintaining reaction efficiency and reproducibility.

Implementation Method 1

Exposing the reactive solution to thermolysis by driving a flow of the reactive solution along the channel from the inlet to an outlet, for a thermolysis time, t, at a pressure, P, and at a thermolysis temperature, T, larger than 200°C, to form thermolysis products including at least one allyl compound

Methodology Applied
Scientific EffectThermolysis: Thermolysis

Implementation Method 2

a heating module arranged for heating the channel at a thermolysis temperature of at least 200°C

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3589609B1Process for the production of allyl compounds by deoxydehydration of glycerol
Publication Date: 2021.09.15 UNIV LIEGE
  • EP3589609B1 patent drawingFigure 1~4
  • EP3589609B1 patent drawingFigure 2~3
  • EP3589609B1 patent drawingFigure 5~6

AI summary

The present invention concerns acontinuous-flow process for the production of allyl compounds by deoxydehydration of glycerol comprising the following steps: (a)Forming a reactive solution by mixing glycerol (1) with: a carboxylic acid (2), and/or a triethyl orthoester, preferably triethyl orthoformate (TEOF); (b)Feeding the reactive solution to an inlet of a channel of a thermolysis microreactor module wherein the channel has an inner hydraulic diameter, D=4A/P, wherein A is the area and P the perimeter of a cross-section of the channel, of not more than 1000µm, (c)Exposing the reactive solution to thermolysis by driving a flow of the reactive solution along the channel from the inlet to an outlet, for a thermolysis time, t, at a pressure, P, and at a thermolysis temperature, T, larger than 200°C, to form thermolysis products including at least one allyl compound; and Recovering the thermolysis products at the outlet and separating the at least one allyl compound from the other thermolysis products