Alkanesulphonic Acid Oxidation Feedback Control

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Solution Overview

Problem

The existing processes for preparing alkanesulphonic acids through the oxidation of alkyl mercaptans, dialkyl disulphides, and dialkyl polysulphides face inefficiencies due to the need for excess oxidizing agents like nitric acid, leading to energy-intensive water separation, harmful nitrogen oxide production, and incomplete conversions that result in elemental sulphur precipitation, causing operational issues in distillation and reducing economic viability.

Innovation Solution

A process that uses pulsed amperometric detection and UV-Vis spectroscopy to determine unreacted sulphur-containing starting compounds and oxidation intermediates, allowing for the controlled addition of additional oxidizing agents to complete the oxidation reaction, thereby ensuring maximum yield and preventing sulphur precipitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If excess oxidizing agent like nitric acid is used to ensure complete oxidation, then oxidation completeness is improved, but harmful nitrogen oxide production increases and energy consumption increases due to water separation

Engineering Contradiction:
Improveoxidation completenessVSAvoidnitrogen oxide production
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback control by continuously monitoring the oxidation reaction progress and adjusting oxidizing agent addition accordingly. This allows complete oxidation to be achieved without using excessive nitric acid, thereby preventing harmful nitrogen oxide production while maintaining oxidation completeness.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the parameter of oxidizing agent addition from fixed excess amount to controlled incremental addition based on reaction monitoring. This parameter change enables precise control of oxidation completeness without the harmful effects of excessive nitric acid usage.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If excess oxidizing agent like nitric acid is used to ensure complete oxidation, then oxidation completeness is improved, but energy consumption increases due to water separation

Engineering Contradiction:
Improveoxidation completenessVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The feedback control system monitors oxidation reaction progress in real-time and adjusts oxidizing agent addition to match actual reaction needs. This eliminates the need for excessive oxidizing agent that would require energy-intensive water separation, while still ensuring complete oxidation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes from fixed excess oxidizing agent addition to dynamic parameter-adjusted addition based on reaction monitoring. This reduces the total amount of oxidizing agent needed, thereby reducing energy consumption for water separation while maintaining oxidation completeness.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If oxidation reaction is not monitored properly, then process simplicity is maintained, but incomplete conversion occurs resulting in elemental sulphur precipitation

Engineering Contradiction:
Improveprocess simplicityVSAvoidconversion completeness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces feedback monitoring of the oxidation reaction to detect unreacted starting materials and oxidation intermediates. This feedback mechanism ensures complete conversion and prevents elemental sulphur precipitation while adding only necessary control complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary monitoring and detection of reaction components to identify when additional oxidizing agent is needed. This preliminary action prevents incomplete conversion and sulphur precipitation before they occur, maintaining process reliability.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If additional oxidizing agent is added to complete oxidation, then conversion completeness is improved, but process complexity increases

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

Solution Approach 1:

The feedback control system automatically determines when additional oxidizing agent is needed based on real-time reaction monitoring. This automated feedback approach improves conversion completeness while minimizing the increase in process complexity through systematic control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements dynamic adjustment of oxidizing agent addition based on reaction progress monitoring. This dynamic approach allows flexible control to achieve complete conversion while adapting to actual reaction conditions, managing process complexity effectively.

Inventive Principle:
Principle #15Dynamics

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 approach enhances the efficiency of alkanesulphonic acid production by ensuring complete conversion, reducing energy costs, minimizing harmful byproduct formation, and preventing operational disruptions from sulphur precipitation, thus improving the economic viability of the process.

Implementation Method 1

oxidizing an alkyl mercaptan, a dialkyl disulphide and/or a dialkyl polysulphide having three to nine sulphur atoms with an oxidizing agent

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

determining unreacted starting compounds and oxidation intermediates by pulsed amperometric detection

Methodology Applied
Scientific EffectAmperometric detection:

Implementation Method 3

determining oxidation intermediates by UV-Vis spectroscopy

Methodology Applied
Scientific EffectUV-Vis spectroscopy: Absorption Spectroscopy

Data Source

PatentEP3386946B1Process for preparing an alkanesulphonic acid
Publication Date: 2021.07.14 EVONIK OPERATIONS GMBH
  • EP3386946B1 patent drawingFigure 1
  • EP3386946B1 patent drawingFigure 2
  • EP3386946B1 patent drawingFigure 3

AI summary

The present invention relates to a process for preparing alkanesulphonic acid by oxidizing an alkyl mercaptan, a dialkyl disulphide and/or a dialkyl polysulphide having three to nine sulphur atoms with an oxidizing agent, wherein additional oxidizing agentis fed into the oxidation if as yet unoxidized alkyl mercaptan and/or unoxidized dialkyl disulphide and/or at least one intermediate from the oxidation of the dialkyl disulphide and/or of the dialkyl polysulphide is present in the reaction output, and a corresponding apparatus for performance of oxidation reactions.