Heterogeneous Catalyst Process for Trioxane Production

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Solution Overview

Problem

Current processes for producing trioxane from formaldehyde are complex, energy-intensive, and result in low conversion rates with high side product formation, necessitating improved methods for efficient production.

Innovation Solution

A process involving an aqueous formaldehyde solution combined with an aprotic compound and a heterogeneous catalyst, such as a solid ion exchange material, in a reactor to convert formaldehyde into trioxane, followed by separation in a low-pressure device and distillation to achieve high conversion rates and purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional extraction process is used for trioxane production, then separation can be achieved, but the process becomes complex and energy-intensive with low conversion rates

Engineering Contradiction:
Improveconversion rateVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the physical state parameter of the reaction system from homogeneous to heterogeneous by using a solid acid catalyst instead of liquid/concensed sulfuric acid. This parameter change enables the reaction mixture to be easily separated into solid catalyst residue and liquid product stream, simplifying the overall process while maintaining high conversion rates of formaldehyde to trioxane

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention extracts the catalyst function from the bulk liquid phase and places it in a solid phase that can be easily separated. The solid acid catalyst is removed from the reaction mixture through simple filtration or decantation, eliminating the need for complex extraction and solvent recovery steps required in conventional processes

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If conventional process with concentrated sulfuric acid is used, then trioxane can be produced, but energy consumption is high and conversion rate is low

Engineering Contradiction:
Improveconversion rateVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The invention changes the catalyst phase parameter from liquid/concensed to solid, which fundamentally alters the reaction system behavior. This enables continuous operation with high conversion rates while reducing energy consumption by eliminating multiple heating, cooling, and distillation steps required in conventional processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The solid acid catalyst enables continuous reaction and separation operations. The catalyst remains in the reactor while product continuously flows through, allowing uninterrupted production with high conversion rates without the energy-intensive batch processing and repeated extraction cycles of conventional methods

Inventive Principle:
Principle #20Continuity of useful action

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 conversion rates of formaldehyde to trioxane with easy separation and recycling of unreacted components, enhancing production efficiency and reducing energy consumption.

Implementation Method 1

The formaldehyde source is contacted with a catalyst in the presence of an aprotic compound to form a cyclic acetal. The catalyst can be a heterogeneous catalyst. For instance, the catalyst may comprise a solid catalyst, such as an ion exchange material.

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

The catalyst may comprise a solid catalyst, such as an ion exchange material.

Methodology Applied
Scientific EffectIon Exchange: Ion Exchange

Implementation Method 3

The product stream is fed to a low pressure separating device. The low pressure separating device produces a cyclic acetal-rich gas stream and an aprotic solvent-rich liquid stream.

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 4

the cyclic acetal-rich gas stream may be quenched and is subsequently fed to a distillation column for further separating the cyclic acetal from unreacted formaldehyde.

Methodology Applied
Scientific EffectDistillation: Distillation

Data Source

PatentEP3774762B1Process for producing a cyclic acetal in a heterogeneous reaction system
Publication Date: 2023.08.30 CELANESE SALES GERMANY
  • EP3774762B1 patent drawingFigure 1
  • EP3774762B1 patent drawingFigure 2
  • EP3774762B1 patent drawing

AI summary

A process for producing a cyclic acetal is disclosed. According to the process, a formaldehyde source is combined with an aprotic compound and contacted with a heterogeneous catalyst which causes the formaldehyde source to convert into a cyclic acetal such as trioxane. The catalyst, for instance, may comprise a solid catalyst such as an ion exchange resin. In one embodiment, the process is used for converting anhydrous formaldehyde gas to trioxane. The anhydrous formaldehyde gas may be produced form an aqueous formaldehyde solution by an extractive distillation. The aprotic compound and the formaldehyde solution may be extracted from the reaction product and recycled into the process.